3,055 results on '"Protéine"'
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52. Reactive Amphiphilic Conjugated Polymers for Inhibiting Amyloid β Assembly.
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Sun, Han, Liu, Jing, Li, Shengliang, Zhou, Lingyun, Wang, Jianwu, Liu, Libing, Lv, Fengting, Gu, Qi, Hu, Baoyang, Ma, Yuguo, and Wang, Shu
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AMPHIPHILES , *CONJUGATED polymers , *AMYLOID , *NITROPHENYL compounds , *CLUSTERING of particles - Abstract
Protein misfolding and aberrant aggregations are associated with multiple prevalent and intractable diseases. Inhibition of amyloid assembly is a promising strategy for the treatment of amyloidosis. Reported here is the design and synthesis of a reactive conjugated polymer, a poly(p‐phenylene vinylene) derivative, functionalized with p‐nitrophenyl esters (PPV‐NP) and it inhibits the assembly of amyloid proteins, degrades preformed fibrils, and reduces the cytotoxicity of amyloid aggregations in living cells. PPV‐NP is attached to the proteins through hydrophobic interactions and irreversible covalent linkage. PPV‐NP also exhibited the capacity to eliminate Aβ plaques in brain slices in ex vivo assays. This work represents an innovative attempt to inhibit protein pathogenic aggregates, and may offer insights into the development of therapeutic strategies for amyloidosis. [ABSTRACT FROM AUTHOR]
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- 2019
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53. Versatile Synthetic Route to Cycloheximide and Analogues That Potently Inhibit Translation Elongation.
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Park, Yongho, Koga, Yumi, Su, Cindy, Waterbury, Amanda L., Johnny, Christopher L., and Liau, Brian B.
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CYCLOHEXIMIDE , *AMINOACYL-tRNA , *PROTEIN synthesis , *RIBOSOMES , *STABILIZING agents - Abstract
Cycloheximide (CHX) is an inhibitor of eukaryotic translation elongation that has played an essential role in the study of protein synthesis. Despite its ubiquity, few studies have been directed towards accessing synthetic CHX derivatives, even though such efforts may lead to protein synthesis inhibitors with improved or alternate properties. Described here is the total synthesis of CHX and analogues, and the establishment of structure–activity relationships (SAR) responsible for translation inhibition. The SAR studies aided the design of more potent compounds, one of which irreversibly blocks ribosomal elongation, preserves polysome profiles, and may be a broadly useful tool for investigating protein synthesis. [ABSTRACT FROM AUTHOR]
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- 2019
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54. Nutrition for master athletes: from challenges to optimisation strategies.
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Lepers, Romuald, Louis, Julien, Vercruyssen, Fabrice, Dupuy, Olivier, and Bernard, Thierry
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SPORTS nutrition ,SUCCESSFUL aging ,YOUNG adults ,POPULATION aging ,MUSCLE mass - Abstract
Copyright of Movement & Sport Sciences / Science & Motricité is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2019
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55. Accurate Determination of 1H‐15N Dipolar Couplings Using Inaccurate Settings of the Magic Angle in Solid‐State NMR Spectroscopy.
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Xue, Kai, Mühlbauer, Max, Mamone, Salvatore, Sarkar, Riddhiman, and Reif, Bernd
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NUCLEAR magnetic resonance spectroscopy , *NITROGEN isotopes , *SOLID state chemistry , *PARAMETER estimation , *ROTORS - Abstract
Magic‐angle spinning (MAS) is an essential ingredient in a wide variety of solid‐state NMR experiments. The standard procedures to adjust the rotor angle are not highly accurate, resulting in a slight misadjustment of the rotor from the magic angle (θRL=tan-12) on the order of a few millidegrees. This small missetting has no significant impact on the overall spectral resolution, but is sufficient to reintroduce anisotropic interactions. Shown here is that site‐specific 1H‐15N dipolar couplings can be accurately measured in a heavily deuterated protein. This method can be applied at arbitrarily high MAS frequencies, since neither rotor synchronization nor particularly high radiofrequency field strengths are required. The off‐MAS method allows the quantification of order parameters for very dynamic residues, which often escape an analysis using existing methods. [ABSTRACT FROM AUTHOR]
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- 2019
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56. Barcoding mit Nukleinsäuren: Anwendung der DNA‐Sequenzierung als molekulares Zählwerk.
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Liszczak, Glen and Muir, Tom W.
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Techniken der Hochdurchsatz‐DNA‐Sequenzierung haben eine Revolution in der Genomik ausgelöst, die in viele Bereiche der Lebens‐ und Naturwissenschaften eingedrungen ist. Die bemerkenswerten Eigenschaften der parallelen DNA‐Sequenzierung, wie hohe Sensitivität und Spezifität, hoher Durchsatz und Multiplexkapazität, führten zu Anwendungen als "molekulare Zählwerke" (molecular counter) für die Entdeckung niedermolekularer und peptidbasierter Inhibitoren, für die Hochdurchsatzbiochemie, die Protein‐ und Zelldetektion, die Diagnostik und sogar die Materialienwissenschaften. Ein wichtiger Aspekt bei der Extrapolation der DNA‐Sequenzierung auf "nichtklassische" Anwendungen besteht in der Anforderung, Nukleinsäure‐Barcodes an die interessierenden Entitäten anzuhängen. In diesem Aufsatz werden die chemischen und biochemischen Ansätze beschrieben, die ein einfaches Nukleinsäure‐Barcoding von proteinhaltigen und nichtproteinhaltigen Materialien ermöglicht haben. Wir zeigen Beispiele für die Verwendung von nachgelagerten Technologien, die durch DNA‐codierte Moleküle ermöglicht wurden. In Anbetracht der Tatsache, dass kommerziell erhältliche Hochdurchsatzsequenzer vor weniger als 15 Jahren eingeführt wurden, glauben wir, dass sich diesbezügliche Anwendungen auch in den kommenden Jahren zur Marktreife entwickeln werden. Strichcodes aus DNA: Die massive parallele DNA‐Sequenzierung bietet eine bemerkenswerte Nachempfindlichkeit, Spezifität und Durchsatzkapazität, die zu ihrer Anwendung als „molekulares Zählwerk" in vielen Forschungsbereichen geführt haben. Dieser Aufsatz beschreibt die Ansätze zur Anbringung von DNA‐Barcodes an biologische und nichtbiologische Materialien und stellt Techniken vor, die durch DNA‐codierte Moleküle ermöglicht wurden. [ABSTRACT FROM AUTHOR]
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- 2019
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57. Surface Attachment Enhances the Thermodynamic Stability of Protein L.
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Ortega, Gabriel, Kurnik, Martin, Dauphin‐Ducharme, Philippe, Li, Hui, Arroyo‐Currás, Netzahualcóyotl, Caceres, Amanda, and Plaxco, Kevin W.
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THERMODYNAMICS , *SURFACE interactions , *BIOTECHNOLOGY , *GUANIDINE , *FREE energy (Thermodynamics) - Abstract
Despite the importance of protein–surface interactions in both biology and biotechnology, our understanding of their origins is limited due to a paucity of experimental studies of the thermodynamics behind such interactions. In response, we have characterized the extent to which interaction with a chemically well‐defined macroscopic surface alters the stability of protein L. To do so, we site‐specifically attached a redox‐reporter‐modified protein variant to a hydroxy‐terminated monolayer on a gold surface and then used electrochemistry to monitor its guanidine denaturation and determine its folding free energy. Comparison with the free energy seen in solution indicates that interaction with this surface stabilizes the protein by 6 kJ mol−1, a value that is in good agreement with theoretical estimates of the entropic consequences of surface‐induced excluded volume effects, thus suggesting that chemically specific interactions with this surface (e.g., electrostatic interactions) are limited in magnitude. [ABSTRACT FROM AUTHOR]
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- 2019
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58. Update zur Diagnose und Therapie der Sarkopenie.
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Goisser, S., Kob, R., Sieber, C. C., and Bauer, J. M.
- Abstract
Copyright of Der Internist is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
- Full Text
- View/download PDF
59. The in vitro effect of oxytocin on synaptic proteins
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Delling, Jan Philipp, Böckers, Tobias M., and Knöll, Bernd
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Proteins ,SHANK protein family ,Oxytocin ,Autismus ,Post-synaptic density ,Synapse ,Gephyrin ,Autism spectrum disorder ,Therapy ,Phelan-McDermid syndrome ,ddc:610 ,Proteine ,DDC 610 / Medicine & health ,SHANK3 - Abstract
SHANK proteins (SHANK1-3) are known as "master"-scaffolding proteins, especially at the postsynaptic density (PSD) of excitatory synapses. The disruption of SHANK-proteins is highly associated with autism spectrum disorder (ASD). ASD represents a neuropsychiatric disease entity that is characterized by a combination of symptoms, including persistent deficits in social communication and interaction, as well as restricted, repetitive patterns of behavior, interests, or activities [DSM-V]. Originating from its major role in mediating social behavior and as a modulator of synaptic transmission it has been hypothesized that oxytocin (OXT) could have beneficial effects on the social deficits seen in ASD. In some animal models of ASD such restoration of social behavior was confirmed, although there is mixed evidence in human studies. More specifically, a recent study showed that OXT restored synaptic plasticity and alleviated behavioral deficits in a SHANK3-deficient rat model for Phelan-McDermid syndrome (PMS) [Harony-Nicolas et al., 2017]. The experiments conducted in this thesis additionally demonstrate that plain OXT-treatment regulates SHANK protein levels in synapses of rat hippocampal neurons. More specifically, OXT-treatment resulted in increased protein levels of all members of the SHANK protein family as reflected by an increased fluorescence intensity of dendritic SHANK-puncta in hippocampal neurons. In addition, a general positive trend concerning the number of synaptic SHANK-clusters was observed after OXT-treatment, which correlates with the increased synaptic protein levels and points towards an increased amount of dendritic SHANK-protein. Since the size of dendritic SHANK1- and SHANK3-clusters were reduced after treatment, OXT might influence the degree of synaptic protein-clustering. The fact that all SHANKs were affected in a similar way suggests a cumulative effect of OXT on general synaptic SHANK-levels by influencing multiple members of this protein family. Confirming the results seen in the immunofluorescent analysis, SHANK1- and SHANK3-levels were also significantly increased in the Western Blot analysis of crude membrane fraction of primary hippocampal neurons, which also contain the PSD. Notably, the analysis of the respective whole-cell homogenate showed a general reversal of these positive trends and even revealed significantly reduced general protein-levels of SHANK3e and SHANK2. Thus, the increased amount of dendritic SHANK-protein seems to rely on a spatial shift of protein pools towards the synaptic compartment, rather than on increased translation. In response to the saturation of dendritic/synaptic protein-levels, general translation could be reduced as a result of a negative feedback loop. Further immunofluorescent analysis did not hint at a spatial shift of protein taking place within the dendritic compartment. Apart from its effects on proteins of excitatory synapses, OXT-treatment resulted in decreased protein levels of Gephyrin at GABAergic postsynapses, as reflected by a decreased fluorescence intensity of dendritic Gephyrin-puncta. These results represent evidence for a direct influence of the OXT-system on the ASD-associated SHANK protein family. OXT-induced effects were pronounced in the analysis of SHANKs. Other excitatory synaptic proteins like VGLUT1 or PSD95 were less affected or not influenced at all. This apparent selectivity needs to be relativized by the fact that only a limited number of proteins was examined in this study (see also 4.5). Gephyrin, which mainly localizes to the postsynapse of inhibitory synapses, was oppositely influenced. This might be an additional mechanism by which OXT affects the excitation/inhibition-balance that has been hypothesized as being crucial in ASD-pathogenesis. As OXT-treatment did not influence presynaptic proteins like VGLUT1 and VGAT to the same degree, postsynaptic scaffolding proteins might be a principal target of OXT-signaling in both excitatory and inhibitory synapses. By affecting proteins like the SHANKs that interact with many other synaptic proteins, OXT could secondarily influence the composition of the PSD at a larger scale or facilitate interaction of certain molecules like AMPAR or NMDAR. The above-mentioned findings justify the assumption that OXT influences protein-levels at excitatory and inhibitory synapses. Accordingly, OXT might have differential effects on social deficits found in patients with ASD, depending on the underlying pathophysiological dysfunction. Since synaptic SHANK3 was increased by OXT-treatment, it might be a suitable candidate for further investigation in patients with PMS (SHANK3-haploinsufficiency syndrome).
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- 2023
60. Mismatch repair deficiency in cutaneous squamous cell carcinoma and its precancerous stages
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Ganjuur, Nomun
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610 Medizin, Gesundheit ,Immun-Checkpoint ,Mismatch ,Plattenepithelkarcinom ,Hautkrebs ,ddc:610 ,Proteine - Abstract
Mutationen an Mismatch-Reparatur (MMR) Proteinen können ein tumoröses Wachstum bedingen. Insbesondere Tumore mit nachgewiesener MMR-Defizienz sprechen mitunter am besten auf neuartige Tumortherapien mit Immuncheckpoint-Inhibitoren (ICI) an. Daher erscheint der MMR-Status beim kutanem Plattenepithelkarzinom (cSCC) sowie ihren präkanzerösen Vorstufen zusätzlichen Aussagewert für die weitere Prognose und Therapie zu haben. Es wurden 102 Gewebeproben mit cSCC und dessen präkanzerösen Stadien analysiert. Die Mehrzahl (95,1%) wiesen eine hochgradige MMR Proteinexpression auf. Bei 4,9% zeigte sich eine niedrige MMR Proteinexpression. Zusammenfassend zeigte sich, dass eine MMR-Defizienz in dieser Tumorgruppe ein seltenes Ereignis ist, jedoch in wenigen Fällen mit bestätigter MMR-Defizienz von großer Bedeutung sein kann, da dies einen positiven prognostischen Faktor in Bezug auf ICI darstellen könnte.
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- 2023
61. Translokation sekretorischer Proteine durch das Sec61/SecY-Translokon
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Jung, Sebastian (Dr. rer. nat.)
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Proteintransport ,ddc:570 ,Periplasma ,Transport ,Proteine ,Endoplasmatisches Retikulum - Abstract
Die Translokation von Proteinen durch die prokaryotische Zytoplasmamembran und die Membran des eukaryotischen Endoplasmatischen Retikulums (ER) ist ein wichtiger Schritt in der Biosynthese sekretorischer Proteine sowie Membranproteinen und erfolgt über den hoch konservierten Sec-Translokationskanal (Sec61 in Eu-, SecY in Prokaryoten). Die Analyse der Translokation durch das Sec61/SecY-Translokon zeigt, dass 1) die ineffiziente Translokation von intrinsisch unstrukturierten Proteinen durch Sec evolutionär konserviert ist und 2) das SecY Proteine mit intrinsisch unstrukturierten Domänen (IDD) nicht effizient translozieren kann. Weiterhin wurde gezeigt, dass 3) die konservierte alpha-Helix (L3) bakterieller Porine ein Motiv negativ geladener Aminosäuren beinhaltet, das essentiell für eine SecY-Translokation ist, und welches Teil eines neuen Qualitätskontrollmechanismus in der Biosynthese bakterieller Porine zu sein scheint.
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- 2023
62. Les algues, un atout dans le cadre d'une alimentation variée.
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Marre-Fournier, Françoise
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Les données nutritionnelles et relatives à la sécurité sanitaire concernant les algues sont encourageantes dans l'optique d'une intégration à une alimentation équilibrée, comme source non conventionnelle de protéines. Alors que la consommation de viande transformée et la surconsommation de viande rouge sont néfastes pour la santé et l'environnement, et que certains pays en développement pourraient être confrontés à une pénurie alimentaire, ces nouveaux aliments semblent constituer un élément de réponse. Nutritional and food safety data on algae are encouraging from the perspective of integration into a balanced diet as an unconventional source of protein. At a time when consumption of processed meat and over-consumption of red meat are harmful to health and the environment, and some developing countries may face food shortages, these new foods appear to be part of the answer. [ABSTRACT FROM AUTHOR]
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- 2021
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63. Nachweis der Proteinexpression von BATF3 im klassischen Hodgkin-Lymphom und dessen Nutzbarkeit als diagnostischer Marker
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Kuchar, Johanna, Leithäuser, Frank, and Knippschild, Uwe
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Basic-leucine zipper transcription factors ,Hodgkin disease ,Lymphoma ,HL ,Proteins ,Lymphogranulomatose ,Biomarker ,ALCL ,Diagnostischer Marker ,Malignes Lymphom ,Diagnosis ,BATF3 ,Proteinexpression ,ddc:610 ,Proteine ,cHL ,DDC 610 / Medicine & health ,Biomarkers - Abstract
Nachweis und Vergleich der BATF3 Proteinexpression in HL, cHL und NHL
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- 2023
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64. Circulardichroismus von Proteinen : ein strukturbasierter Frenkel-Exziton Theorie Ansatz
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Hofer, Michael
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spectroscopy ,theoretical physics ,Circulardichroismus ,Proteine ,Spektroskopie ,Circular dichroism ,Theoretische Physik ,proteins - Abstract
Circular dichroism (CD) is a sensitive method for the structural characterisation of proteins that has found diverse applications in pharmaceutical research and industry, biochemistry and structural biology, however, accurate theoretical tools for the prediction of CD are rare. In this thesis we present a new, origin-independent, theory of CD based on a structure-based Frenkel exciton approach. The electronic structure and excited states of the protein are calculated by ab-initio TDDFT methods based on which atomic transition charges (ATCs) are fitted that enable an efficient and accurate calculation of the electrostatic interaction even for large proteins. Inhomogeneous broadening of the CD spectra arising from the dynamics of the protein is derived from molecular dynamics (MD) simulations, revealing a Gaussian distributed fluctuation of the site energies and is taken into account explicitly, from the MD trajectory or via a Monte Carlo approach. Additionally those fluctuations in the site energies are shown to be uncorrelated between different sites and those of the excitonic couplings to be negligible. The agreement between theory and experiment is found to be remarkably good, in both, the explicit structure-based calculation and the fit to the typical spectra of the according secondary structure. An additional study on short alanine-helices reproduces the experimental length-dependence of the spectra very well. Circulardichroismus (CD) ist eine sensitive spektroskopische Methode zur Strukturbestimmung von Proteinen mit diversen Anwendungen in der pharmazeutischen Forschung und Industrie, Biochemie sowie Strukturbiologie. Dennoch gibt es nur wenige präzises Methoden, zur theoretischen Vorhersage von CD Spektren. In dieser Masterarbeit präsentieren wir eine neue, ursprungsunabhängig, Theorie des CD aufbauend auf einem strukturbasierten Frenkel-Exziton Ansatz. Hierbei werden die optisch angeregten Zustände des Proteins ab-initio mit TDDFT berechnet und auf atomare Partialladungen gefittet, um eine effiziente und akkurate Berechnung der elektrostatischen Wechselwirkungen selbst für große Proteine zu gewährleisten. Die inhomogene Verbreiterung der Spektren, verursacht durch die Dynamik des Proteins werden mit Molekulardynamiksimulationen (MD) untersucht und die resultierende gaußverteilte Fluktuation der Anregungsenergien entweder explizit von der MD Trajektorie berechnet oder über einen Monte-Carlo Ansatz modelliert. Des Weiteren wird nachgewiesen, dass diese Fluktuationen gänzlich unkorreliert auftreten und jene der exzitonischen Kopplungen keinen Einfluss auf die resultierenden Spektren haben. Die Übereinstimmung zwischen Theorie und Experiment ist für die gefitteten und die strukturbasierten Spektren ausgezeichnet. Eine weitere Untersuchung an sehr kurzen Helices spiegelt auch die Längenabhängigkeit der Spektren sehr gut wider. eingereicht von Michael Hofer Abweichender Titel laut Übersetzung der Verfasserin/des Verfassers Masterarbeit Universität Linz 2023
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- 2023
65. Meso puževa, novotkriveni stari izvor proteina u ljudskoj prehrani
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Lušnic Polak, Mateja, Polak, Tomaž, Brglez, Nina, and Demšar, Lea
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chiocciole ,carne di chiocciola ,parametri fisico-chimici ,proteine ,composizione degli acidi grassi ,proprietà sensoriali ,puževi ,meso puževa ,fizikalno-kemijski parametri ,protein ,sastav masnih kiselina ,senzorna svojstva ,Schnecken ,Schneckenfleisch ,physikochemische Parameter ,Protein ,Fettsäurezusammensetzung ,sensorische Eigenschaften ,caracoles ,carne de caracol ,parámetros fisicoquímicos ,proteína ,snails ,snail meat ,physicochemical parameters ,fatty acid composition ,sensory properties - Abstract
The aim of this study was to determine the physicochemical parameters, i.e. water, protein, fat, ash, sodium and carbohydrate content and energy value, as well as fatty acid composition and pH of snail meat from two species, Cornu aspersum maximum and Cornu aspersum Müller. The snail meat was found to have relatively high protein content (13.12 g/100 g vs. 16.53 g/100 g), low fat content (0.89 g/100 g vs. 1.21 g/100 g), and low energy value (343.8 kJ vs. 379.2 kJ). The pH of snail meat was very high (8.59 vs. 8.19). On average, snail meat has a favourable fatty acid composition as it contains 27.08 wt. % saturated (SFA), 19.00 wt. % monounsaturated, and 53.92 wt. % polyunsaturated fatty acids (PUFA). It has a favourable PUFA/SFA ratio (1.99), but an unfavourable n-6/n-3 ratio (20.33) and a relatively high proportion of trans fatty acids (3.93 wt. %). The fatty acid profile of snail meat is dominated by linoleic acid (20.89 wt. %), arachidonic acid (13.27 wt. %), oleic acid (12.67 wt. %), nonadecanoic acid (10.23 wt. %), and stearic acid (10.08 wt.%). The aim of our study was also to verify the culinary value of snail meat. For this purpose, two snail meat pâtés of acceptable sensory quality were prepared. The panel evaluated the sensory quality of the pâté made from the meat (foot and liver) of the snail Cornu aspersum Müller significantly worse than the pâté made from the meat of the snail Cornu aspersum maximum, mainly due to the unpleasant aroma, in which the soapy, sweet and spicy components predominated, as well as the absence of the snail meat aroma., Cilj ovog rada bio je odrediti fizikalno-kemijske parametre, tj. udio vode, bjelančevina, masti, pepela, natrija i ugljikohidrata te energetsku vrijednost, kao i sastav masnih kiselina i pH mesa puževa dviju vrsta, Cornu aspersum maximum i Cornu aspersum Müller. Utvrđeno je da meso puža ima relativno visok udio proteina (13,12 g/100 g u odnosu na 16,53 g/100 g), nizak udio masti (0,89 g/100 g u odnosu na 1,21 g/100 g) i nisku energetsku vrijednost (343,8 kJ u odnosu na 379,2 kJ). pH mesa puževa bio je vrlo visok (8,59 naspram 8,19). Meso puževa u prosjeku ima povoljan sastav masnih kiselina jer sadrži 27,08 mas. % zasićenih (SFA), 19,00 % mononezasićenih i 53,92 % polinezasićenih masnih kiselina (PUFA). Ima povoljan omjer PUFA/SFA (1,99), ali nepovoljan omjer n-6/n-3 (20,33) i relativno visok udio transmasnih kiselina (3,93 %). Profilom masnih kiselina u mesu puževa dominiraju linolna kiselina (20,89 %), arahidonska kiselina (13,27 %), oleinska kiselina (12,67 %), nonadekanska kiselina (10,23 %) i stearinska kiselina (10,08 %). Cilj našeg istraživanja također je bio provjeriti kulinarsku vrijednost mesa puževa. U tu svrhu pripremljene su dvije paštete od puževog mesa prihvatljive senzorske kvalitete. Panel je značajno lošije ocijenio senzorsku kvalitetu paštete od mesa (stopala i jetra) puža Cornu aspersum Müller od paštete od mesa puža Cornu aspersum maximum, uglavnom zbog neugodne arome, u kojoj se prevladavaju sapunaste, slatke i ljute komponente, kao i odsustvo arome puževog mesa., Ziel dieser Studie war es, die physikalisch-chemischen Parameter, d. h. den Wasser-, Protein-, Fett-, Asche-, Natrium- und Kohlenhydratgehalt und den Energiewert, sowie die Fettsäurezusammensetzung und den pH-Wert von Schneckenfleisch zweier Arten, Cornu aspersum maximum und Cornu aspersum Müller, zu bestimmen. Das Schneckenfleisch wies einen relativ hohen Proteingehalt (13,12 g/100 g gegenüber 16,53 g/100 g), einen niedrigen Fettgehalt (0,89 g/100 g gegenüber 1,21 g/100 g) und einen niedrigen Energiewert (343,8 kJ gegenüber 379,2 kJ) auf. Der pH-Wert von Schneckenfleisch war sehr hoch (8,59 vs. 8,19). Im Durchschnitt hat Schneckenfleisch eine günstige Fettsäurezusammensetzung, da es 27,08 Gew.-% gesättigte (SFA), 19,00 Gew.-% einfach ungesättigte und 53,92 Gew.-% mehrfach ungesättigte Fettsäuren (PUFA) enthält. Es hat ein günstiges PUFA/SFA-Verhältnis (1,99), aber ein ungünstiges n-6/n-3-Verhältnis (20,33) und einen relativ hohen Anteil an trans-Fettsäuren (3,93 Gew.-%). Das Fettsäureprofil von Schneckenfleisch wird dominiert von Linolsäure (20,89 Gew.-%), Arachidonsäure (13,27 Gew.-%), Ölsäure (12,67 Gew.-%), Nonadecansäure (10,23 Gew.-%) und Stearinsäure (10,08 Gew.-%). Das Ziel unserer Studie war es auch, den kulinarischen Wert von Schneckenfleisch zu überprüfen. Zu diesem Zweck wurden zwei Schneckenfleischpasteten von akzeptabler sensorischer Qualität zubereitet. Die Jury bewertete die sensorische Qualität der Pastete aus dem Fleisch (Fuß und Leber) der Schnecke Cornu aspersum Müller deutlich schlechter als die Pastete aus dem Fleisch der Schnecke Cornu aspersum maximum, was vor allem auf das unangenehme Aroma zurückzuführen war, bei dem die seifigen, süßen und würzigen Komponenten überwogen, sowie auf das Fehlen des Schneckenfleischaromas., El objetivo de este trabajo fue determinar los parámetros físico-químicos, es decir, la proporción de agua, proteínas, grasas, cenizas, sodio y carbohidratos, así como el valor energético, la composición de ácidos grasos y el pH de la carne de caracoles de dos especies, Cornu aspersum maximum y Cornu aspersum Müller. Se encontró que la carne de caracol tiene un contenido de proteína relativamente alto (13,12 g/100 g frente a 16,53g / 100g), bajo contenido de grasa (0,89g / 100g frente a 1,21g /100g) y bajo valor energético (343,8g / 100g kJ frente a 379,2 kJ). El pH de la carne de caracol era muy alto (8,59 frente a 8,19). En promedio, la carne de caracol tiene una composición de ácidos grasos favorable, ya que contiene 27,08% en peso de saturados (SFA), 19,00% monoinsaturados y 53,92% de ácidos grasos poliinsaturados (PUFA). Tiene una relación PUFA/SFA favorable (1,99), pero una relación n-6/n-3 desfavorable (20,33) y una proporción relativamente alta de ácidos grasos trans (3,93% en peso). El perfil de ácidos grasos en la carne de caracol está dominado por ácido linoleico (20,89 %), ácido araquidónico (13,27 %), ácido oleico (12,67 %), ácido nonadecanoico (10,23 %) y ácido esteárico (10,08 %). El objetivo de nuestra investigación también fue comprobar el valor culinario de la carne de caracol. Para ello fueron preparados dos patés de carne de caracol de aceptable calidad sensorial. El panel calificó la calidad sensorial del paté de carne de caracol Cornu aspersum Müller (patas e hígado) significativamente peor que la carne de paté Cornu aspersum maximum, principalmente debido al aroma desagradable, en el que predominan los componentes jabonosos, dulces y picantes, así como la ausencia de aroma a carne de caracol., Questo studio aveva lo scopo di determinare i parametri fisico-chimici, cioè il contenuto di acqua, proteine, grassi, ceneri, sodio e carboidrati, nonché il valore energetico, la composizione degli acidi grassi e il pH della carne di chiocciola (impropriamente chiamata lumaca di terra) di due specie, Cornu aspersum maximum e Cornu aspersum Müller. È stato riscontrato che la carne di chiocciola ha un contenuto proteico relativamente elevato (13,12 g/100 g contro 16,53 g/100 g), un basso contenuto di grassi (0,89 g/100 g contro 1,21 g/100 g) e un basso valore energetico (343,8 kJ rispetto a 379,2 kJ). Il pH della carne di chiocciola è risultato molto alto (8,59 contro 8,19). In media, la carne di chiocciola ha una composizione favorevole di acidi grassi, poiché contiene il 27,08 % di acidi grassi saturi (SFA), il 19,00 % di acidi grassi monoinsaturi e il 53,92 % di acidi grassi polinsaturi (PUFA). Ha un rapporto PUFA/SFA favorevole (1,99), ma un rapporto n-6/n-3 sfavorevole (20,33) e una percentuale relativamente alta di acidi grassi trans (3,93%). Il profilo degli acidi grassi nella carne di chiocciola è dominato dall’acido linoleico (20,89%), seguito dall’acido arachidonico (13,27%), dall’acido oleico (12,67%), dall’acido nonadecilico o nonadecanoico (10,23%) e dall’acido stearico (10,08%). L’obiettivo della nostra ricerca era anche quello di verificare il valore culinario della carne di chiocciola. A tale scopo sono stati preparati due pâté di carne di chiocciola di qualità sensoriale accettabile. Il panel ha valutato la qualità sensoriale del pâté di carne di chiocciola Cornu aspersum Müller (zampe e fegato) significativamente peggiore rispetto al pâté di carne Cornu aspersum maximum, principalmente a causa dell’aroma sgradevole, in cui predominano le componenti saponose, dolci e piccanti, nonché per l’assenza dell’aroma della carne di chiocciola.
- Published
- 2023
66. Untersuchung zur Proteinexpression der Embryonalmarker Lefty und Nodal im Merkelzellkarzinom
- Author
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Ardabili, Samira
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Merkel-Zellkarzinom ,610 Medizin, Gesundheit ,Tumor ,Prognose ,ddc:610 ,Proteine ,Marker - Abstract
Das Merkelzellkarzinom (MCC) ist ein hoch aggressiver Tumor, dessen Behandlung sich vor allem im fortgeschrittenen Stadium höchst problematisch gestaltet. Es konnte gezeigt werden, dass es signifikant häufiger linksseitig lokalisiert ist. Das Ziel war deshalb die Expression der TGF-\(\beta\) assoziierten Proteine Lefty und Nodal im MCC zu bestimmen und mit klinischen Parametern zu korrelieren. 29 Patienten wurden immunhistochemisch auf die Expression der Proteine Lefty und Nodal untersucht. Durch Anwendung des H-Scores wurde die Expression quantifiziert. Im Rahmen dieser Arbeit konnte gezeigt werden, dass niedrige Expressions-Level von Lefty im primären MCC einen starken Prädiktor für MCC-spezifische Todesfälle darstellen. Die Eignung von Lefty und Nodal als diagnostisch oder sogar therapeutisch bedeutsame Marker für die Behandlung des MCC sollte daher in weiterführenden Studien untersucht werden.
- Published
- 2022
67. Noncovalent Carbon‐Bonding Interactions in Proteins.
- Author
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Mundlapati, V. Rao, Sahoo, Dipak Kumar, Bhaumik, Suman, Jena, Subhrakant, Chandrakar, Amol, and Biswal, Himansu S.
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PROTEIN analysis , *CARBON compounds , *CHEMICAL bonds , *HYDROGEN bonding , *BOND energy (Chemistry) - Abstract
Carbon bonds (C‐bonds) are the highly directional noncovalent interactions between carbonyl‐oxygen acceptors and sp3‐hybridized‐carbon σ‐hole donors through n→σ* electron delocalization. We have shown the ubiquitous existence of C‐bonds in proteins with the help of careful protein structure analysis and quantum calculations, and have precisely determined C‐bond energies. The importance of conventional noncovalent interactions such as hydrogen bond (H‐bonds) and halogen bond (X‐bonds) in the structure and function of biological molecules are well established, while carbon bonds C‐bonds have still to be recognized. We have shown that C‐bonds are present in proteins, contribute enthalpically to the overall hydrophobic interaction and play a significant role in the photodissociation mechanism of myoglobin and the binding of nucleobases to proteins. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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68. Biocatalytic "Oxygen‐Fueled" Atom Transfer Radical Polymerization.
- Author
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Enciso, Alan E., Fu, Liye, Lathwal, Sushil, Olszewski, Mateusz, Wang, Zhenhua, Das, Subha R., Russell, Alan J., and Matyjaszewski, Krzysztof
- Subjects
- *
ATOM transfer reactions , *GLUCOSE oxidase , *HORSERADISH peroxidase , *CHAIN scission , *REFRIGERANTS - Abstract
Atom transfer radical polymerization (ATRP) can be carried out in a flask completely open to air using a biocatalytic system composed of glucose oxidase (GOx) and horseradish peroxidase (HRP) with an active copper catalyst complex. Nanomolar concentrations of the enzymes and ppm amounts of Cu provided excellent control over the polymerization of oligo(ethylene oxide) methyl ether methacrylate (OEOMA500), generating polymers with high molecular weight (Mn>70 000) and low dispersities (1.13≤Đ≤1.27) in less than an hour. The continuous oxygen supply was necessary for the generation of radicals and polymer chain growth as demonstrated by temporal control and by inducing hypoxic conditions. In addition, the enzymatic cascade polymerization triggered by oxygen was used for a protein and DNA functionalized with initiators to form protein‐b‐POEOMA and DNA‐b‐POEOMA bioconjugates, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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69. Rationally Designed Semisynthetic Natural Product Analogues for Stabilization of 14‐3‐3 Protein–Protein Interactions.
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Andrei, Sebastian A., de Vink, Pim, Sijbesma, Eline, Han, Ling, Brunsveld, Luc, Kato, Nobuo, Ottmann, Christian, and Higuchi, Yusuke
- Subjects
- *
NATURAL products , *PROTEIN-protein interactions , *MOLECULAR dynamics , *X-ray crystallography , *HYDROGEN bonding - Abstract
Abstract: The natural product family of fusicoccanes are stabilizers of 14‐3‐3 mediated protein–protein interactions (PPIs), some of which possess antitumor activity. In this study, the first use of molecular dynamics (MD) to rationally design PPI stabilizers with increased potency is presented. Synthesis of a focused library, with subsequent characterization by fluorescence polarization, mutational studies, and X‐ray crystallography confirmed the power of the MD‐based design approach, revealing the potential for an additional hydrogen bond with the 14‐3‐3 protein to lead to significantly increased potency. Additionally, these compounds exert their action in a cellular environment with increased potency. The newly found polar interaction could provide an anchoring point for new small‐molecule PPI stabilizers. These results facilitate the development of fusicoccanes towards drugs or tool compounds, as well as allowing the study of the fundamental principles behind PPI stabilization. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
70. Reactivity and Selectivity of Iminium Organocatalysis Improved by a Protein Host.
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Nödling, Alexander R., Świderek, Katarzyna, Castillo, Raquel, Hall, Jonathan W., Angelastro, Antonio, Morrill, Louis C., Jin, Yi, Tsai, Yu‐Hsuan, Moliner, Vicent, and Luk, Louis Y. P.
- Subjects
- *
ORGANOCATALYSIS , *STEREOSELECTIVE reactions , *STREPTAVIDIN , *ENANTIOSELECTIVE catalysis , *INTERMEDIATES (Chemistry) - Abstract
Abstract: There has been growing interest in performing organocatalysis within a supramolecular system as a means of controlling reaction reactivity and stereoselectivity. Here, a protein is used as a host for iminium catalysis. A pyrrolidine moiety is covalently linked to biotin and introduced to the protein host streptavidin for organocatalytic activity. Whereas in traditional systems stereoselectivity is largely controlled by the substituents added to the organocatalyst, enantiomeric enrichment by the reported supramolecular system is completely controlled by the host. Also, the yield of the model reaction increases over 10‐fold when streptavidin is included. A 1.1 Å crystal structure of the protein–catalyst complex and molecular simulations of a key intermediate reveal the chiral scaffold surrounding the organocatalytic reaction site. This work illustrates that proteins can be an excellent supramolecular host for driving stereoselective secondary amine organocatalysis. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
71. Gold‐Catalyzed C–S Aryl‐Group Transfer in Zinc Finger Proteins.
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de Paiva, Raphael E. F., Du, Zhifeng, Nakahata, Douglas H., Lima, Frederico A., Corbi, Pedro P., and Farrell, Nicholas P.
- Subjects
- *
GOLD catalysts , *ARYL group , *ZINC-finger proteins , *NUCLEOCAPSID structure , *MOLECULAR structure of viral capsids , *ORGANOMETALLIC compounds - Abstract
Abstract: Reaction of the Au–C N chelate [Au(bnpy)Cl2] with the full‐length zinc finger (ZnF; ZnCys3His) of HIV nucleocapsid protein NCp7 results in C–S aryl transfer from the AuIII organometallic species to a cysteine of the ZnF. The reaction is general and occurs even for finger 3 of the transcription factor Sp1, containing a ZnCys2His2 coordination sphere. This reaction is the first demonstration of group transfer from a coordination compound to biologically important zinc fingers, and is especially noteworthy for the ZnCys2His2 transcription factors. The work expands the corpus of organometallic species which can efficiently modify biomolecules through C‐atom transfer. The electronic features of the gold compound leading to this unexpected reaction were explored by X‐ray absorption spectroscopy. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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72. Cofactor Biogenesis in Cysteamine Dioxygenase: C−F Bond Cleavage with Genetically Incorporated Unnatural Tyrosine.
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Wang, Yifan, Griffith, Wendell P., Li, Jiasong, Koto, Teruaki, Wherritt, Daniel J., Fritz, Elizabeth, and Liu, Aimin
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- *
CYSTEAMINE , *DIOXYGENASES , *ORIGIN of life , *TYROSINE , *NUCLEAR magnetic resonance spectroscopy - Abstract
Abstract: Cysteamine dioxygenase (ADO) is a thiol dioxygenase whose study has been stagnated by the ambiguity as to whether or not it possesses an anticipated protein‐derived cofactor. Reported herein is the discovery and elucidation of a Cys‐Tyr cofactor in human ADO, crosslinked between Cys220 and Tyr222 through a thioether (C−S) bond. By genetically incorporating an unnatural amino acid, 3,5‐difluoro‐tyrosine (F2‐Tyr), specifically into Tyr222 of human ADO, an autocatalytic oxidative carbon–fluorine bond activation and fluoride release were identified by mass spectrometry and 19F NMR spectroscopy. These results suggest that the cofactor biogenesis is executed by a powerful oxidant during an autocatalytic process. Unlike that of cysteine dioxygenase, the crosslinking results in a minimal structural change of the protein and it is not detectable by routine low‐resolution techniques. Finally, a new sequence motif, C‐X‐Y‐Y(F), is proposed for identifying the Cys‐Tyr crosslink. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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73. Halogenaromatische π‐Wechselwirkungen modulieren die Verweilzeit von Inhibitoren.
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Heroven, Christina, Georgi, Victoria, Ganotra, Gaurav K., Brennan, Paul, Wolfreys, Finn, Wade, Rebecca C., Fernández‐Montalván, Amaury E., Chaikuad, Apirat, and Knapp, Stefan
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HALOGENS , *AROMATIC compounds , *MOLECULAR interactions , *PROTEIN fractionation , *RECOMBINANT proteins , *AFFINITY chromatography - Abstract
Abstract: Längere Verweilzeiten vom Wirkstoff am Zielmolekül (Target) können zu länger anhaltender Arzneimittelwirksamkeit, verbesserten pharmakodynamischen Eigenschaften und kinetischer Selektivität gegenüber Antitargets mit schnellen Dissoziationsraten führen. Bisher wurden nur wenige Strategien gefunden, um die Verweilzeit des Wirkstoffs rational zu modulieren und dadurch diese Schlüsseleigenschaft in den Medikamentenentwicklungsprozess zu integrieren. Die Wechselwirkung zwischen einem Halogenrest am Inhibitor und einer aromatischen Seitenkette im Zielprotein kann die Inhibitorverweilzeit signifikant erhöhen. Als Modell für den archetypischen Bindungsmodus eines ATP‐kompetitiven Typ‐I‐Inhibitors mit einer konstitutiv aktiven Kinase wurde die Wechselwirkung der Serin/Threonin‐Kinase Haspin mit 5‐Iodotubercidin(5‐iTU)‐Derivaten verwendet und gezeigt, dass die Inhibitorverweilzeit deutlich mit der Größe und Polarisierbarkeit des Halogenatoms zunimmt. Mithilfe kinetischer, thermodynamischer und struktureller Messungen sowie Bindungsenergieberechnungen liefern wir eine detaillierte mechanistische Charakterisierung der halogenaromatischen π‐Interaktionen in Haspin‐Inhibitor‐Komplexen. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
74. Tunable and Photoswitchable Chemically Induced Dimerization for Chemo‐optogenetic Control of Protein and Organelle Positioning.
- Author
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Chen, Xi and Wu, Yao‐Wen
- Subjects
- *
PROTEINS , *DIMERIZATION , *PHOTOSENSITIZATION , *CELL physiology , *OPTOGENETICS - Abstract
Abstract: The spatiotemporal dynamics of proteins and organelles play an important role in controlling diverse cellular processes. Optogenetic tools using photosensitive proteins and chemically induced dimerization (CID), which allow control of protein dimerization, have been used to elucidate the dynamics of biological systems and to dissect the complicated biological regulatory networks. However, the inherent limitations of current optogenetic and CID systems remain a significant challenge for the fine‐tuning of cellular activity at precise times and locations. Herein, we present a novel chemo‐optogenetic approach, photoswitchable chemically induced dimerization (psCID), for controlling cellular function by using blue light in a rapid and reversible manner. Moreover, psCID is tunable; that is, the dimerization and dedimerization degrees can be fine‐tuned by applying different doses of illumination. Using this approach, we control the localization of proteins and positioning of organelles in live cells with high spatial (μm) and temporal (ms) precision. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
75. The effect of protein concentration on corrosion of nitinol alloy.
- Author
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Rozali, A. A., Masdek, N. R. Nik, Murad, M. Che, Salleh, Z., and Koay, M. H.
- Subjects
- *
PROTEIN analysis , *CORROSION in alloys , *NICKEL-titanium alloys , *SIMULATION methods & models , *ELECTROCHEMICAL analysis - Abstract
Abstract: The corrosion behaviour for nitinol alloy under simulated biological conditions with the presence of proteins was investigated using electrochemical methods. The electrochemical tests were performed with the addition of bovine serum albumin with concentrations of 0 %, 2 %, 4 %, 6 %, 8 % and 10 % at 37 °C. The electrochemical method used in this study was potentiodynamics polarization to obtain the corrosion rate of the samples. The composition of the bio‐implant materials was studied using X‐ray diffraction. The samples showed that they did not undergo any significant change in term of composition. Based on the results obtained, it can be concluded that nitinol alloys have a good corrosion resistant towards all concentrations. Thus, nitinol alloys can perform well with or without the presence of protein‐containing solutions thus they are compatible to use as implant materials in human body environment. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
76. Expression of the Frizzled receptors and their co-receptors in calcified human aortic valves.
- Author
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Siddique, Ateeque, Yu, Bin, Khan, Kashif, Buyting, Ryan, Al-Kindi, Hamood, Alaws, Hossny, Rhéaume, Eric, Tardif, Jean-Claude, Cecere, Renzo, and Schwertani, Adel
- Subjects
- *
AORTIC stenosis , *GENE expression , *AORTIC valve , *CELLULAR mechanics , *IMMUNOHISTOCHEMISTRY - Abstract
The cellular mechanisms that induce calcific aortic stenosis are yet to be unraveled. Wnt signaling is increasingly being considered as a major player in the disease process. However, the presence of Wnt Frizzled (Fzd) receptors and co-receptors LRP5 and 6 in normal and diseased human aortic valves remains to be elucidated. Immunohistochemistry and quantitative polymerase chain reaction were used to determine Fzd receptor expression in normal and calcified human aortic valve tissue, as well as human aortic valve interstitial cells (HAVICs) isolated from calcified and normal human aortic valves. There was significantly higher mRNA expression of 4 out of the 10 Fzd receptors in calcified aortic valve tissues and 8 out of the 10 in HAVICs, and both LRP5/6 co-receptors in calcified aortic valves ( P < 0.05). These results were confirmed by immunohistochemistry, which revealed abundant increase in immunoreactivity for Fzd3, 7, and 8, mainly in areas of lipid core and calcified nodules of diseased aortic valves. The findings of abundant expression of Fzd and LRP5/6 receptors in diseased aortic valves suggests a potential role for both canonical and noncanonical Wnt signaling in the pathogenesis of human aortic valve calcification. Future investigations aimed at targeting these molecules may provide potential therapies for aortic valve stenosis. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
77. Influence de la substitution des graines de soja (Glycine max) par celles de niébé (Vigna unguiculata) et du taux de protéines du régime sur les performances des pintadeaux de race locale au Burkina Faso
- Author
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Seydou Ouattara, Valérie Marie Christiane Bougouma-Yaméogo, Aimé Joseph Nianogo, and Boukari Savadogo
- Subjects
Numida meleagris ,pintade ,niébé ,soja ,protéine ,alimentation des animaux ,Animal culture ,SF1-1100 - Abstract
Cette étude a eu pour but d’évaluer les effets de l’utilisation des graines torréfiées de niébé dans l’alimentation des pintadeaux de race locale, en substitution à celles de soja, sur leurs performances zootechniques et leur rentabilité économique. Trois cent pintadeaux de 12 jours d’âge ont été répartis en 12 lots. Quatre régimes alimentaires iso-énergétiques, incorporant 5,0 % et 10,0 % de graines torréfiées de niébé ou de soja respectivement au démarrage et à la croissance-finition ont été préparés. Ces régimes avaient des niveaux protéiques de 17,5 % ou 20,0 % au démarrage, puis de 15,0 % ou 17,5 %, pendant la croissance-finition. Les régimes démarrage ont été servis du 13e au 68e jour et ceux de croissance-finition du 69e au 222e jour. Les paramètres zootechniques (poids vif, gain de poids et ingérés alimentaires) ont été suivis toutes les deux semaines. A la fin de l’essai, quatre sujets par lot ont été abattus pour évaluer les rendements carcasses et de certains organes. La rentabilité économique des différents régimes a été évaluée. L’incorporation des graines torréfiées de niébé n’a induit des différences significatives pour aucun des paramètres étudiés, à l’exception de quelques paramètres des rendements carcasses. En revanche, la différence de niveaux de protéines a engendré des différences significatives en faveur des régimes les plus riches en protéines pour la plupart des paramètres mesurés ; la durée d’élevage des pintades des régimes plus riches a été réduite de deux semaines. Les graines torréfiées de niébé peuvent donc être utilisées dans l’alimentation des pintadeaux de race locale, en substitution à celles de soja.
- Published
- 2017
- Full Text
- View/download PDF
78. Développement et optimisation de potentiels simplifiés de la famille OPEP et étude de molécules thérapeutiques contre la COVID-19
- Author
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Binette, Vincent and Mousseau, Normand
- Subjects
Simulation numérique ,Protein ,Structure prediction ,Prédiction structurelle ,COVID-19 ,Protéine ,Molecular dynamics ,aaOPEP - Abstract
La bio-modélisation numérique est un domaine hautement multidisciplinaire à la frontière entre la biologie, la physique, les mathématiques et l'informatique. Il s'agit d'un domaine en pleine effervescence grâce à une habile exploitation des avancées informatiques et algorithmiques. Parmi ses sujets d'étude, on retrouve les protéines, des molécules de grand intérêt. En effet, elles sont des nanomachines jouant des fonctions primordiales pour la survie de tout organisme. En plus de leurs fonctions naturelles, certaines protéines sont associées au développement de diverses maladies ou pourraient servir de molécules thérapeutiques. La vision traditionnelle de la biologie moléculaire stipule que les fonctions des protéines sont étroitement liées à leur structure tri-dimensionnelle elle-même déterminée par les propriétés physico-chimiques de la séquence en acides aminés. Ainsi, l'étude de la structure est indispensable. Les méthodes de la bio-modélisation numérique, en partenariat avec l'expérience, sont particulièrement appropriées pour l'étude des protéines. Cette thèse s'articulera donc autour de trois classes de méthodes qui permettent d'étudier divers aspects des protéines. Le premier chapitre présentera les améliorations apportées à PEP-FOLD, une méthode simplifiée pour la prédiction structurelle \emph{de novo} des petits peptides. Deux des trois éléments-clés de PEP-FOLD ont été peaufinés, l'alphabet structurel et le potentiel gros-grain sOPEP, avec comme résultat une amélioration de la qualité des prédictions. Cette nouvelle version est comparée aux méthodes de prédictions utilisant les plus récents développements de l'apprentissage machine. Le second chapitre présentera les résultats de simulations numériques sut deux petites molécules thérapeutiques contre la COVID-19, grâce à des méthodes basées sur la physique. En collaboration avec les résultats expérimentaux, nos simulations montrent que nos deux molécules pourraient prévenir des interactions cruciales pour l'émergence de la maladie. Finalement, le dernier chapitre présentera quelques résultats préliminaires au développement du potentiel simplifié aaOPEP, qui permettra d'étudier les processus d'agrégation et de fibrillation de la protéine $\beta$-amyloïde, associés à l'apparition de la maladie d'Alzheimer. Ce processus étant fondamentalement multi-échelle, au niveau spatial et temporel, le développement de méthodes simplifiées est essentiel pour obtenir le portrait global du phénomène., Molecular modeling is a multidisciplinary enterprise combining the fields of biology, physics, mathematics and informatics. By utilizing improvements in both computer hardware and algorithms, the field is experiencing a spectacular growth in the past two decades. Proteins are nanomachines and play multiple essential functions in the life of every organisms. Additionally, proteins are also associated with the emergence of many diseases and could also be used as therapeutic molecules. In the classical view of molecular biology, protein's functions are closely related to its tri-dimensional structure, which is encoded by the chemical properties of the amino acid sequence. Therefore, the study of protein's structure is of fundamental importance. Tools from molecular modeling are, in partnership with experimental techniques, very well suited to study proteins. The following thesis will be divided into three main classes of techniques, each able to study a wide range of protein's characteristics. The first chapter present improvements made to PEP-FOLD, a simplified, freely-available online and successful technique for \textit{de novo} peptide-structure prediction. Two of the three key components of PEP-FOLD were revisited in this work; the structural alphabet and the coarse-grained potential sOPEP. These modifications lead to an important increase in the quality of PEP-FOLD's predictions. A thorough comparison with state-of-the-art machine learning techniques is made and we highlight key successes and possible future improvements. The second chapter present the study of potential therapeutic molecules against COVID-19 using physics-based techniques. These results, combined with experimental data from immunobinding assay and SPR microscopy, showed that our two small molecules could prevent key interactions between the wild-type/mutant SARS-CoV-2 and the cells of the host and therefore could potentially be potent therapeutic molecules against COVID-19. Finally, the last chapter present preliminary results about the development of the new aaOPEP forcefield designed to study the multi-scale process of amyloid-$\beta$ aggregation and fibrillation, associated with the Alzheimer disease. This new potential will take the core ideas of the coarse-grained potential OPEP into the all-atom regime and will allow to study bigger systems over longer time-scale.
- Published
- 2022
79. Application of deep eutectic solvents in protein extraction and purification
- Author
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Hou Bowen, Rabia Durrani, André Delavault, Erwann Durand, Jiang Chenyu, Long Yiyang, Song Lili, Song Jian, Huan Weiwei, and Gao Fei
- Subjects
Protéine ,General Chemistry ,U50 - Sciences physiques et chimie ,Biodégradabilité ,Utilisation des déchets ,Solvant ,Chemical engineering ,Extraction par solvant ,Protéine animale ,ddc:660 ,Protéine végétale ,Purification ,Propriété physicochimique - Abstract
Deep eutectic solvents (DESs) are a mixture of hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) molecules that can consist, respectively, of natural plant metabolites such as sugars, carboxylic acids, amino acids, and ionic molecules, which are for the vast majority ammonium salts. Media such as DESs are modular tools of sustainability that can be pointed toward the extraction of bioactive molecules due to their excellent physicochemical properties, their relatively low price, and accessibility. The present review focuses on the application of DESs for protein extraction and purification. The in-depth effects and principles that apply to DES-mediated extraction using various renewable biomasses will be discussed as well. One of the most important observations being made is that DESs have a clear ability to maintain the biological and/or functional activity of the extracted proteins, as well as increase their stability compared to traditional solvents. They demonstrate true potential for a reproducible but more importantly, scalable protein extraction and purification compared to traditional methods while enabling waste valorization in some particular cases.
- Published
- 2022
- Full Text
- View/download PDF
80. A method for traceable protein quantification using isotope dilution ICP-MS and its application on the tau protein
- Author
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Lemke, Nora, Panne, Ulrich, Theuring, Franz, and Weller, Michael
- Subjects
ID-ICP-MS ,Metrologie ,543 Analytische Chemie ,Tau-Protein ,Rückführbarkeit ,Isotopenverdünnung ,Isotope dilution ,Unsicherheitsbudget ,proteins ,quantification ,tau protein ,traceability ,metrology ,ICP-MS ,Proteine ,ddc:543 ,Quantifizierung ,uncertainty budget - Abstract
In dieser Arbeit wurde ein Verfahren zur rückführbaren Proteinquantifizierung unter Verwendung von Schwefelisotopenverdünnung mit induktiv gekoppelter Plasmamassenspektrometrie (ID-ICP-MS) entwickelt. Die Methode dient zur zuverlässigen Quantifizierung laborinterner Proteinstandards. Sie eignet sich nur zur Analyse reiner Proteine, deren Stöchiometrie bekannt ist, da die Proteinkonzentration aus dem Schwefelgehalt bestimmt wird. Nicht proteingebundener Schwefel wird durch Membranfiltration von der Proteinfraktion abgetrennt und mit ID-ICP-MS quantifiziert. Der Gesamtschwefelgehalt in der Probe wird ebenfalls mittels ID-ICP-MS quantifiziert und um die Menge an ungebundenem Schwefel korrigiert. Die Optimierung der Probenvorbereitung zeigte, dass ein Aufschluss die Unsicherheit des Ergebnisses verbessert. Für die Methodenentwicklung wurden ein zertifiziertes Rinderserumalbumin-Referenzmaterial (BSA), sowie ein kommerzielles Avidin verwendet. Die Bestimmung der Proteinmassenfraktionen und Unsicherheitsbudgets erfolgte nach Korrektur für den ungebundenen Schwefel (0,4 % für BSA, 30 % für Avidin). Die Methode wurde auf das Tau-Protein angewendet, das ein Biomarker für die sogenannten „Tauopathien“ ist – eine Gruppe neurodegenerativer Krankheiten, die die Alzheimer-Krankheit und die frontotemporale Demenz einschließen. Durch Verwendung eines isotopenangereicherten Spikes, der an das SI-System angebunden ist, wurde die metrologische Rückführbarkeit für den Massenanteil des Tau-Proteins erreicht. Dieser Tau-Standard wurde zur absoluten Quantifizierung toxischer transgener Tau-Spezies in der löslichen Hirnfraktion transgener Mäuse verwendet. Die entwickelte Methode ist für die rückführbare Quantifizierung von Proteinen zur Verwendung als Standards in der biologischen und medizinischen Forschung anwendbar. Sie zeigte eine ähnliche Präzision wie etablierte Verfahren, erforderte jedoch weniger Probenvorbereitung und keine spezies-spezifischen Standards., In this work, a method for traceable protein quantification using sulphur isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) was developed. The method is intended for the reliable quantification of in-house protein standards. It is only suited for pure protein formulations for proteins of known stoichiometry because the protein concentration is determined from the sulphur content. Non-protein bound sulphur is separated from the protein fraction by membrane filtration and is quantified by ID-ICP-MS. The total sulphur content in the sample is as well quantified by ID-ICP-MS and corrected for the amount of non-protein bound sulphur. Optimisation of the sample preparation showed that digestion improves the uncertainty of the result. For method development, a certified reference material bovine serum albumin (BSA) and a commercial avidin were used. The protein mass fractions with full uncertainty budgets were determined after correction for unbound sulphur. The developed procedure was applied to the tau protein, which is a biomarker fort he so-called „tauopathies“ – a group of neurodegenerative diseases including Alzheimer’s disease and Frontotemporal dementia. By employing an isotopically enriched spike, which is linked to the SI system, full metrological traceability was achieved for the tau mass fraction. The mass fraction of (0.328 ± 0.036) g kg-1 for tau was determined by ID-ICP-MS and confirmed by amino acid analysis. This tau standard was used for the absolute quantification of toxic transgenic tau species in the soluble brain fraction of transgenic mice. The developed method is applicable for the traceable quantification of proteins for use as standards in biological and medical research. The precision of the method was similar to established absolute protein quantification procedures while requiring less sample preparation and no species-specific standards.
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- 2022
81. Application of deep eutectic solvents in protein extraction and purification
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Bowen, Hou, Durrani, Rabia, Delavault, André, Durand, Erwann, Chenyu, Jiang, Yiyang, Long, Lilia, Song, Jian, Song, Weiwei, Huan, Fei, Gao, Bowen, Hou, Durrani, Rabia, Delavault, André, Durand, Erwann, Chenyu, Jiang, Yiyang, Long, Lilia, Song, Jian, Song, Weiwei, Huan, and Fei, Gao
- Abstract
Deep eutectic solvents (DESs) are a mixture of hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) molecules that can consist, respectively, of natural plant metabolites such as sugars, carboxylic acids, amino acids, and ionic molecules, which are for the vast majority ammonium salts. Media such as DESs are modular tools of sustainability that can be pointed toward the extraction of bioactive molecules due to their excellent physicochemical properties, their relatively low price, and accessibility. The present review focuses on the application of DESs for protein extraction and purification. The in-depth effects and principles that apply to DES-mediated extraction using various renewable biomasses will be discussed as well. One of the most important observations being made is that DESs have a clear ability to maintain the biological and/or functional activity of the extracted proteins, as well as increase their stability compared to traditional solvents. They demonstrate true potential for a reproducible but more importantly, scalable protein extraction and purification compared to traditional methods while enabling waste valorization in some particular cases.
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- 2022
82. The Importance of tRNA Modification and SSD1 Status for Protein Homeostasis and Cell Viability
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Khonsari, Bahar
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Zelle ,Hefestamm ,Messenger-RNS ,Transfer-RNS ,Synthasen ,Proteine ,Pseudouridin - Published
- 2022
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83. Überleben am Rande der bewohnbaren Welt
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Martin, Elvira and Floss, Harald (Prof. Dr.)
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Ernährung ,Mittelpaläolithikum ,Pollenanalysen ,nutrionally basics ,carbohydrates ,vitamin D ,OIS 3 ,Reproduktion und Ernährung ,anatomisch moderne Menschen ,Faunadaten Fundstellen ,ernährungsphysiologische Grundlagen ,Paläolithikum ,Knochenmark ,Skelettteilverwertung ,hunting season ,Rentier ,Mineralstoffe ,anatomically modern human ,Kohlenhydrate ,Neanderthals ,Makroreste von Pflanzen ,Lipide ,fulfillment of nutrition demands ,Bedarfsdeckung ,Neandertaler ,dominante Tierart ,vitamins ,Hühnervögel ,Pflanzen DNA ,Stärkebestimmung auf Zähnen und Steinartefakten ,horse ,Europe ,dental microwear ,Schlacht- und Schnittspuren ,Fleisch ,reindeer ,Brandspuren ,Europa ,Fische ,essentielle Fettsäuren ,bone marrow ,Boviden ,Knochenmarkgewinnung ,residue analysis ,essential fatty acids ,reproduction and diet ,anthropogene Spuren ,lipids ,Gebrauchsspurenanalysen von Steinartefakten ,mammoth ,Knochenfett ,starch analysis teeth, stone artefacts ,letzte Eiszeit ,Aurignacien ,Vitamine ,Pferd ,Dental micorwear ,monospezifische Jagd ,Jagdmuster ,Klimaphasen ,isotope analysis ,Gravettien ,Prähistorische Archäologie ,Jagdsaison ,last ice age ,Rückstandsanalysen ,proteins ,Isotopenanalysen ,Mammut ,Proteine ,diet ,bovids ,nutritionally basics - Abstract
Für den Zeitraum der OIS 3 sind im nördlichen Europa (>43°bis 52° nördlicher Breite) viele Fundplätze nachgewiesen, die von Neandertalern und modernen Menschen besiedelt waren. Dabei stellt sich die Frage, auf welcher Nahrungsgrundlage die Hominiden ihr Leben dort gestaltet haben. Waren sie von ständigem Hunger bedroht oder konnten sie ein Leben in Gesundheit mit optimalen Bedingungen für die Fortpflanzung führen? Es wurden die tierischen Ressourcen der OIS 3 für 80 Fundplätze in der o.g. Region und nach folgenden Merkmalen aufgenommen: dominante Tierart, monospezifische Jagd, Vorkommen kleiner Tiere, Skelettteilrepräsentanz, Jagdsaison und anthropogene Spuren. Eine statistische Auswertung ergab, dass die Unterschiede zwischen dem Mittelpaläolithikum und dem Aurignacien kleiner waren, als zwischen dem Aurignacien und dem Gravettien, was bedeutet, dass sich Neandertaler in Bezug auf die tierischen Ressourcen ähnlich verhalten haben wie der AMH des Aurignacien. Die tierischen Ressourcen bildeten die Grundlage zur Berechnung der Bedarfsdeckung an Energie, Makro- und Mikronährstoffen. Darauf aufbauend konnte berechnet werden, welche Mengen an Makro- und Mikronährstoffen, die sich als Defizite (Kohlenhydrate, Calcium, Vitamin D, C, Folsäure) aus einer ausschließlichen Ernährung aus tierischen Ressourcen ergeben, noch durch Pflanzen gedeckt werden mussten. Die Pflanzen der OIS 3 wurden aus der Biomisation, die das Stage 3 Projekt (Davis und van Andel, 2003) zur Verfügung stellte, mit Wildpflanzennährwerten verknüpft. Auf dieser Basis war es möglich, die noch fehlenden Makro- und Mikronährstoffe zu berechnen. Bei erfolgreicher Jagd und Kenntnis der Pflanzenstandorte war es möglich, ausreichend Energie sowie fast alle Makro- und Mikronährstoffe zu konsumieren. Die Auswirkungen der mit dieser auf Proteinen und Fetten beruhenden, veränderten Stoffwechsellage, sowie die Folgen defizitärer Nährstoffe bleiben ungeklärt.
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- 2022
84. La Bioinformatica per apprendere la Biologia: uno strumento didattico innovativo
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De Leo, Francesca, Licata, Luana, Marabotti, Anna, and Via, Allegra
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Bioinformatica ,Proteine ,Acidi Nucleici ,Didattica ,Genomica ,RNA ,ELIXIR ,DNA - Abstract
ELIXIR-IIB ha partecipato allaFiera Didacta Italia, che ha avutoluogo dal 20 al 22 maggio 2022 a Firenze (Fortezza da Basso) con un seminario interamente dedicato alla bioinformatica, non come disciplina a sé, ma come strumento innovativo per l’apprendimento della biologia. Il seminario, dal titolo “La bioinformatica per apprendere la biologia: uno strumento didattico innovativo”, è statoerogato mediante tecniche di apprendimento attivo, interattivo e collaborativo, venerdì 20 maggio dalle 16:30 alle 18 nella Palazzina Lorenese (sala S6). Attraverso un approccio pratico ed efficace, proposto dalla piattaforma del training di ELIXIR-IIB, si è mostratoai docenti della scuola superiore come utilizzare risorse della bioinformatica per studiare alcuni selezionati argomenti di biologia, come la struttura del DNA e delle proteine o le funzioni e l’evoluzione del genoma. In questo modo è stato possibile comprendere come la bioinformatica possa essere un valido strumento di supporto didattico per esplorare e comprendere la biologia. In altre parole, non si tratterebbe di inserire la bioinformatica nel curriculum come disciplina a sé stante, ma di utilizzarne le risorse e gli strumenti per imparare la biologia in modo efficace e innovativo. Nella prima parte del seminario, si sono propostealcune risorse bioinformatiche da utilizzare per lo studio di selezionati argomenti di biologia molecolare e cellulare. La restante parte del seminario, è stata dedicata a discutere con i docenti presenti le sfide e difficoltà dell’approccio proposto. ELIXIR-IIB offre inoltre ai docenti interessati, un successivo percorso formativo per l’apprendimento di risorse e strumenti bioinformatici utili a insegnare la biologia in modo efficace e innovativo. Allegra Via (Cnr-Ibpm)allegra.via@cnr.it Francesca De Leo (Cnr-Ibiom)francesca.deleo@cnr.it Luana Licata (Università di Roma "Tor Vergata" e Fondazione Human Technopole, Milano)luana.licata@uniroma2.it Anna Marabotti (Dipartimento di Chimica e Biologia “A. Zambelli”, Università di Salerno)amarabotti@unisa.it
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- 2022
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85. Soy and soy-based products in the athlete’s diet.
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Laza, Valeria
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- *
PROTEINS , *ATHLETES , *MUSCLE growth - Abstract
Proteins in the athlete’s diet are used for muscle growth and repair; cell regulation; immune and neurological functions; nutrient transport and structural support. Protein needs depend on many variables: energy intake, exercise type (1.2 to 1.5 g/ kg/day for endurance, and 1.2 to 1.7 g/kg/day for strength athletes), duration and intensity of exercise, and the training phase (novice vs. trained). The best sources of proteins preferred by athletes are whey, egg white and soy derivative products. Soy has many virtues, as well as a long record of unhealthy compounds (also called antinutrients): endocrine disruptors, saponins, enzyme inhibitors, goitrogens, phytates, pesticides, etc. Athletes prefer their convenience and ease of use, so they consume protein supplements such as protein concentrates and isolates, which are highly refined and processed forms of soy. Beside the negative effects of soy antinutrients, high ingestion of soy protein supplements has detrimental results: dehydration and calcium loss (due to high protein intake); presence of toxic substances (aluminum, nitrites, lysinoalanine) in processed soy-based products. During the last 3-4 decades, soy has become a very controversial and complicated topic. For every study showing the nutritional value of soy, another one claims the detrimental effects on health, so, reviewing the data on soy is very confusing. Moreover, in order to clarify the truth, many other confounding dietary factors should be taken into consideration. For soy to be a healthy food, it is recommended to be organic, used in a properly fermented form, occasionally, and in moderate amounts. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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86. Protein Catenation Enhances Both the Stability and Activity of Folded Structural Domains.
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Wang, Xiao‐Wei and Zhang, Wen‐Bin
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- *
PROTEIN stability , *PROTEIN folding , *PROTEIN structure , *CATENANES , *DIMERIZATION , *GREEN fluorescent protein - Abstract
Catenanes are intriguing molecular architectures with unique properties. Herein, we report the cellular synthesis of protein catenanes containing folded structural domains, aided by synergy between p53 dimerization and SpyTag/SpyCatcher chemistry. Concatenation of green fluorescent protein (GFP) was shown to increase chemical stability without disrupting the fluorescence properties, and concatenated dihydrofolate reductase (DHFR) exhibited a melting temperature around 4 °C higher and catalytic activity around 27 % higher than the wild-type DHFR and the cyclic/linear controls. Catenation also confers considerable proteolytic resistance on DHFR. The results suggest that catenation could enhance both the stability and activity of folded proteins, thus making topology engineering an attractive approach for tailoring protein properties without varying their native sequences. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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87. Nutrition guidelines for competitive tennis.
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Teodor, Dragoș-Florin
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- *
TENNIS players , *SPORTS nutrition , *ELECTROLYTES , *HEALTH - Abstract
To provide evidence-based nutritional recommendations for performance tennis players. Players should particularly focus their exercise program on the adequate and appropriate consumption of four primary nutrient categories - electrolytes, carbohydrates, protein and fat. For most players, the International Tennis Federation recommends a minimum of approximately 2500 calories a day, although some players may require in excess of 3500 calories. The American College of Sports Medicine and the National Athletic Trainers Association have recommended that athletes should consume in general 30-60 g/h CHO during exercise. It is important for tennis players to eat plenty of complex carbohydrate foods, especially those with a low glycemic index to help boost glycogen stores. Protein is crucial for maintaining, building and repairing the tennis players' muscles. Players should consume 15-20 g of protein within 30 minutes after a tennis match. Fat takes the longest time to digest, and thus, it is not a good source of quick energy during exercise. Vitamins and minerals do not provide a source of energy but are needed to derive energy from nutrients that are consumed. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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88. Dendrimer and dendrimer-conjugate protein complexes and protein coronas.
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Chen, Junjie and Banaszak Holl, Mark M.
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- *
DENDRIMERS , *BIO-imaging sensors , *BIOINDICATORS , *PROTEINS , *SMALL molecules - Abstract
Dendrimers and dendrimer conjugates are widely employed for biological applications such as bio-imaging and drug delivery. Understanding the interaction between dendrimers and their biological environment is key to evaluating the efficacy and safety of these materials. Proteins can form an adsorbed layer, termed a 'protein corona', on dendrimers in either a non-specific or specific fashion. A tight-binding, non-exchangeable corona is defined as a 'hard' corona, whereas a loosely bound, highly exchangeable corona is called a 'soft' corona. Recent research indicates that small molecules conjugated to the polymer surface can induce protein structural change, leading to tighter protein-dendrimer binding and further protein aggregation. This 'triggered' corona formation on dendrimer and dendrimer conjugates is reviewed and discussed along with the existing hard or soft corona model. This review describes the triggered corona model to further the understanding of protein corona formation. [ABSTRACT FROM AUTHOR]
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- 2017
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89. Highly Ordered Self-Assembly of Native Proteins into 1D, 2D, and 3D Structures Modulated by the Tether Length of Assembly-Inducing Ligands.
- Author
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Yang, Guang, Ding, Hong ‐ ming, Kochovski, Zdravko, Hu, Rongting, Lu, Yan, Ma, Yu ‐ qiang, Chen, Guosong, and Jiang, Ming
- Subjects
- *
NANOSTRUCTURES , *MOLECULAR self-assembly , *LIGANDS (Chemistry) , *SMALL molecules , *ETHYLENE oxide , *NANOWIRES - Abstract
In nature, proteins self-assemble into various structures with different dimensions. To construct these nanostructures in laboratories, normally proteins with different symmetries are selected. However, most of these approaches are engineering-intensive and highly dependent on the accuracy of the protein design. Herein, we report that a simple native protein LecA assembles into one-dimensional nanoribbons and nanowires, two-dimensional nanosheets, and three-dimensional layered structures controlled mainly by small-molecule assembly-inducing ligands RnG ( n=1, 2, 3, 4, 5) with varying numbers of ethylene oxide repeating units. To understand the formation mechanism of the different morphologies controlled by the small-molecule structure, molecular simulations were performed from microscopic and mesoscopic view, which presented a clear relationship between the molecular structure of the ligands and the assembled patterns. These results introduce an easy strategy to control the assembly structure and dimension, which could shed light on controlled protein assembly. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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90. Quantum Mechanics/Molecular Mechanics Study on the Photoreactions of Dark- and Light-Adapted States of a Blue-Light YtvA LOV Photoreceptor.
- Author
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Chang, Xue ‐ Ping, Gao, Yuan ‐ Jun, Fang, Wei ‐ Hai, Cui, Ganglong, and Thiel, Walter
- Subjects
- *
QUANTUM mechanics , *PHOTOCHEMISTRY , *FLAVIN mononucleotide , *CHROMOPHORES , *SPECTRUM analysis - Abstract
The dark- and light-adapted states of YtvA LOV domains exhibit distinct excited-state behavior. We have employed high-level QM(MS-CASPT2)/MM calculations to study the photochemical reactions of the dark- and light-adapted states. The photoreaction from the dark-adapted state starts with an S1→T1 intersystem crossing followed by a triplet-state hydrogen transfer from the thiol to the flavin moiety that produces a diradical intermediate, and a subsequent internal conversion that triggers a barrierless C−S bond formation in the S0 state. The energy profiles for these transformations are different for the four conformers of the dark-adapted state considered. The photochemistry of the light-adapted state does not involve the triplet state: photoexcitation to the S1 state triggers C−S bond cleavage followed by recombination in the S0 state; both these processes are essentially barrierless and thus ultrafast. The present work offers new mechanistic insights into the photoresponse of flavin-containing blue-light photoreceptors. [ABSTRACT FROM AUTHOR]
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- 2017
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91. Highly Charged Protein Ions: The Strongest Organic Acids to Date.
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Zenaidee, Muhammad A., Leeming, Michael G., Zhang, Fangtong, Funston, Toby T., and Donald, William A.
- Subjects
- *
PROTEINS , *ORGANIC acids , *CYTOCHROME c , *MYOGLOBIN , *SPECTROMETRY - Abstract
The basicity of highly protonated cytochrome c (cyt c) and myoglobin (myo) ions were investigated using tandem mass spectrometry, ion-molecule reactions (IMRs), and theoretical calculations as a function of charge state. Surprisingly, highly charged protein ions (HCPI) can readily protonate non-polar molecules and inert gases, including Ar, O2, and N2 in thermal IMRs. The most HCPIs that can be observed are over 130 kJ mol−1 less basic than the least basic neutral organic molecules known (tetrafluoromethane and methane). Based on theoretical calculations, it is predicted that protonated cyt c and myo ions should spontaneously lose a proton to vacuum for charge states in which every third residue is protonated. In this study, HCPIs are formed where every fourth residue on average is protonated. These results indicate that protein ions in higher charge states can be formed using a low-pressure ion source to reduce proton-transfer reactions between protein ions and gases from the atmosphere. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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92. Native Mass Spectrometry from Common Buffers with Salts That Mimic the Extracellular Environment.
- Author
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Susa, Anna C., Xia, Zijie, and Williams, Evan R.
- Subjects
- *
AMMONIUM , *COMPLEX ions , *EXTRACELLULAR matrix , *MASS spectrometry , *NITROGEN compounds , *PROTEIN structure , *BUFFER solutions , *IONIC strength - Abstract
Nonvolatile salts are essential for the structures and functions of many proteins and protein complexes but can severely degrade performance of native mass spectrometry by adducting to protein and protein complex ions, thereby reducing sensitivity and mass measuring accuracy. Small nanoelectrospray emitters are used to form protein and protein complex ions directly from high-ionic-strength (>150 m m) nonvolatile buffers with salts that mimic the extracellular environment. Charge-state distributions are not obtained for proteins and protein complexes from six commonly used nonvolatile buffers and ≥150 m m Na+ with conventionally sized nanoelectrospray emitter tips but are resolved with 0.5 μm tips. This method enables mass measurements of proteins and protein complexes directly from a variety of commonly used buffers with high concentrations of nonvolatile salts and eliminates the need to buffer exchange into volatile ammonium buffers traditionally used in native mass spectrometry. [ABSTRACT FROM AUTHOR]
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- 2017
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93. Observation of CH⋅⋅⋅π Interactions between Methyl and Carbonyl Groups in Proteins.
- Author
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Perras, Frédéric A., Marion, Dominique, Boisbouvier, Jérôme, Bryce, David L., and Plevin, Michael J.
- Subjects
- *
CARBONYL group , *METHYL groups , *PROTEIN structure , *MOLECULAR interactions , *CARBON-hydrogen bonds - Abstract
Protein structure and function is dependent on myriad noncovalent interactions. Direct detection and characterization of these weak interactions in large biomolecules, such as proteins, is experimentally challenging. Herein, we report the first observation and measurement of long-range 'through-space' scalar couplings between methyl and backbone carbonyl groups in proteins. These J couplings are indicative of the presence of noncovalent C−H⋅⋅⋅π hydrogen-bond-like interactions involving the amide π network. Experimentally detected scalar couplings were corroborated by a natural bond orbital analysis, which revealed the orbital nature of the interaction and the origins of the through-space J couplings. The experimental observation of this type of CH⋅⋅⋅π interaction adds a new dimension to the study of protein structure, function, and dynamics by NMR spectroscopy. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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94. Single-Molecule Photoactivation FRET: A General and Easy-To-Implement Approach To Break the Concentration Barrier.
- Author
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Peng, Sijia, Sun, Ruirui, Wang, Wenjuan, and Chen, Chunlai
- Subjects
- *
SINGLE molecules , *PHOTOACTIVATION , *FLUOROPHORES , *FLUORESCENCE resonance energy transfer , *MOLECULAR dynamics - Abstract
Single-molecule fluorescence resonance energy transfer (sm-FRET) has become a widely used tool to reveal dynamic processes and molecule mechanisms hidden under ensemble measurements. However, the upper limit of fluorescent species used in sm-FRET is still orders of magnitude lower than the association affinity of many biological processes under physiological conditions. Herein, we introduce single-molecule photoactivation FRET (sm-PAFRET), a general approach to break the concentration barrier by using photoactivatable fluorophores as donors. We demonstrate sm-PAFRET by capturing transient FRET states and revealing new reaction pathways during translation using μ m fluorophore labeled species, which is 2-3 orders of magnitude higher than commonly used in sm-FRET measurements. sm-PAFRET serves as an easy-to-implement tool to lift the concentration barrier and discover new molecular dynamic processes and mechanisms under physiological concentrations. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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95. Modulation of amyloid assembly by glycosaminoglycans: from mechanism to biological significance.
- Author
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Quittot, Noé, Sebastiao, Mathew, and Bourgault, Steve
- Subjects
- *
AMYLOID , *GLYCOSAMINOGLYCANS , *POLYSACCHARIDES , *EXTRACELLULAR matrix , *CELL adhesion - Abstract
Glycosaminoglycans (GAGs) are long and unbranched polysaccharides that are abundant in the extracellular matrix and basement membrane of multicellular organisms. These linear polyanionic macromolecules are involved in many physiological functions from cell adhesion to cellular signaling. Interestingly, amyloid fibrils extracted from patients afflicted with protein misfolding diseases are virtually always associated with GAGs. Amyloid fibrils are highly organized nanostructures that have been historically associated with pathological states, such as Alzheimer's disease and systemic amyloidoses. However, recent studies have identified functional amyloids that accomplish crucial physiological roles in almost all living organisms, from bacteria to insects and mammals. Over the last 2 decades, numerous reports have revealed that sulfated GAGs accelerate and (or) promote the self-assembly of a large diversity of proteins, both inherently amyloidogenic and non-aggregation prone. Despite the fact that many studies have investigated the molecular mechanism(s) by which GAGs induce amyloid assembly, the mechanistic elucidation of GAG-mediated amyloidogenesis still remains the subject of active research. In this review, we expose the contribution of GAGs in amyloid assembly, and we discuss the pathophysiological and functional significance of GAG-mediated fibrillization. Finally, we propose mechanistic models of the unique and potent ability of sulfated GAGs to hasten amyloid fibril formation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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96. Separating Dipolar and Chemical Exchange Magnetization Transfer Processes in 1H-CEST.
- Author
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Yuwen, Tairan, Sekhar, Ashok, and Kay, Lewis E.
- Subjects
- *
MAGNETIZATION transfer , *CHEMICAL shift (Nuclear magnetic resonance) , *SEPARATION (Technology) , *CHEMICAL reactions , *AMIDES - Abstract
An amide 1H-Chemical Exchange Saturation Transfer (CEST) experiment is presented for studies of conformational exchange in proteins. The approach, exploiting spin-state-selective magnetization transfer, completely suppresses undesired NOE-based dips in CEST profiles so that chemical exchange processes can be studied. The methodology is demonstrated with applications involving proteins that interconvert on the millisecond timescale between major and invisible minor states, and accurate amide 1H chemical shifts of the minor conformer are obtained in each case. The spin-state-selective magnetization transfer approach offers unique possibilities for quantitative studies of protein exchange through 1H-CEST. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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97. Regimes of Biomolecular Ultrasmall Nanoparticle Interactions.
- Author
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Boselli, Luca, Polo, Ester, Castagnola, Valentina, and Dawson, Kenneth A.
- Subjects
- *
NANOPARTICLES , *NANOFABRICS , *NANOSTRUCTURED materials , *BIOMOLECULAR electronics , *MICROSCOPY - Abstract
Ultrasmall nanoparticles (USNPs), usually defined as NPs with core in the size range 1-3 nm, are a class of nanomaterials which show unique physicochemical properties, often different from larger NPs of the same material. Moreover, there are also indications that USNPs might have distinct properties in their biological interactions. For example, recent in vivo experiments suggest that some USNPs escape the liver, spleen, and kidney, in contrast to larger NPs that are strongly accumulated in the liver. Here, we present a simple approach to study the biomolecular interactions at the USNPs bio-nanointerface, opening up the possibility to systematically link these observations to microscopic molecular principles. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
98. Association of Increase in Some Biochemical Components with Flax Resistance to Powdery Mildew.
- Author
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Aly, A., Mansour, M., and Mohamed, H.
- Subjects
POWDERY mildew diseases ,ALKALOIDS ,PEROXIDASE ,PHENOLS ,PROTEINS ,PROLINE - Abstract
Copyright of Gesunde Pflanzen is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
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99. Production and antioxidant capacity of bioactive peptides from plant biomass to counteract lipid oxidation
- Author
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Frédéric Fine, Romain Kapel, Sophie Beaubier, Pierre Villeneuve, Isidora Ilic, Erwann Durand, Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Démarche intégrée pour l'obtention d'aliments de qualité (UMR QualiSud), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Institut Agro - Montpellier SupAgro, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Département Performances des systèmes de production et de transformation tropicaux (Cirad-PERSYST), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Terres Inovia, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL), and Terres Innovia
- Subjects
Antioxidant ,030309 nutrition & dietetics ,medicine.medical_treatment ,F60 - Physiologie et biochimie végétale ,Biomass ,Peptide ,Context (language use) ,Review Article ,Oxydation biochimique ,Applied Microbiology and Biotechnology ,Hydrolysate ,Antioxidants ,Food processing and manufacture ,03 medical and health sciences ,[SPI]Engineering Sciences [physics] ,0404 agricultural biotechnology ,Lipid oxidation ,Q02 - Traitement et conservation des produits alimentaires ,Biomasse ,medicine ,[SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering ,TX341-641 ,Food science ,2. Zero hunger ,chemistry.chemical_classification ,0303 health sciences ,Plant biomass ,Nutrition. Foods and food supply ,Proteins ,Biological activity ,04 agricultural and veterinary sciences ,Q01 - Sciences et technologies alimentaires - Considérations générales ,Protéine ,TP368-456 ,040401 food science ,Antioxydant ,Amino acid ,chemistry ,Peptides ,Food Science ,Biotechnology - Abstract
Preventing lipid oxidation, especially with the polyunsaturated fat-based products, is a major concern in sectors as agri-food and cosmetic. Even though the efficiency of synthetic antioxidants has been recognized, both consumers and manufacturers are looking for more innovative, healthy and quality products while rejecting synthetic additives due to their concern about safety, along with their environmental impact issues. In this context, plant biomass, which have shown to be rich in compounds, have raised interest for the isolation of novel naturally occurring antioxidants. Among their myriad of molecules, bioactive peptides, which are biologically active sequence of amino acid residues of proteins, seem to be of a great interest. Therefore, the number of identified amino acids sequences of bioactive peptides from plant biomass with potential antioxidant action is progressively increasing. Thus, this review provides a description of 129 works that have been made to produce bioactive peptides (hydrolysate, fraction and/or isolate peptide) from 55 plant biomass, along with the procedure to examine their antioxidant capacity (until 2019 included). The protein name, the process, and the method to concentrate or isolate antioxidant bioactive peptides, along with their identification and/or specificity were described. Considering the complex, dynamic and multifactorial physico-chemical mechanisms of the lipid oxidation, an appropriate in-vitro methodology should be better performed to efficiently probe the antioxidant potential of bioactive peptides. Therefore, the results were discussed, and perspective for antioxidant applications of bioactive peptides from plant biomass was argued., Graphical abstract Image 1, Highlights • Exhaustive description of 129 works made to produce bioactive peptides from 55 plant biomass. • Controlled proteolysis can be used as a sustainable strategy to produce peptides. • Presentation of the important points to consider when estimating the antioxidant capacity of peptides. • Methodology should be improved to better probe the antioxidant potential of peptides.
- Published
- 2021
- Full Text
- View/download PDF
100. Cyanogenic, carotenoids and protein composition in leaves and roots across seven diverse population found in the world cassava germplasm collection at CIAT, Colombia
- Author
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Maria Alejandra Ospina, Jorge Luna, Hernán Ceballos, Luis Augusto Becerra Lopez-Lavalle, Thierry Tran, Sandra Salazar, Julien Ricci, Luis Fernando Londoño, John Belalcazar, Dominique Dufour, and Monica Pizarro
- Subjects
Germplasm ,Glycoside cyanogène ,medicine.medical_treatment ,Cyanide ,Caroténoïde ,Manioc ,Rainforest ,Biology ,Industrial and Manufacturing Engineering ,chemistry.chemical_compound ,Valine ,medicine ,Q04 - Composition des produits alimentaires ,Carotenoid ,chemistry.chemical_classification ,Genetic diversity ,Tropical agriculture ,Carotene ,Feuille ,food and beverages ,Composition chimique ,Protéine ,Valeur nutritive ,Horticulture ,chemistry ,Acide aminé ,Food Science - Abstract
The objective of this study was to characterise the nutritional potential of leaves and identify a diversity centre with low cyanide and high nutrient content among 178 Latin American cassava genotypes. This field‐based collection, represents the seven diversity centres, held at The International Center for Tropical Agriculture (CIAT Palmira, Colombia) by the Cassava Program. The cyanide, all‐trans‐β‐carotene and lutein concentrations in cassava leaves ranged from 346 ‐ 7484 ppm dry basis (db), from 174‐547 μg.g‐1 db and 15 ‐ 181 μg · g‐1 db respectively. Cassava leaves also showed significant levels of essential amino acids leucine, lysine, phenylalanine, valine and threonine, and average total protein content of 26.24 g · 100g‐1 db. Among seven diversity centres, South American rainforest group showed low cyanide and high carotene content in leaves. In addition, VEN77 and PAN51 genotypes stood out for having low cyanide in leaves and roots and high carotene in leaves. This genetic diversity can be used to select high potential progenitors for breeding purposes.
- Published
- 2020
- Full Text
- View/download PDF
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