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Required metrological tools, such as higher order reference measurements procedures, pure substance and matrix certified reference materials, are established for small well defined molecules. Difficulties still remain in the provision of SI traceable standards in the area of larger biomolecules such as peptides/proteins. The provision of Primary Calibration Reference Services has been identified as a core technical competency for National Measurement Institutes (NMIs). A concept has been elaborated by the Focus Group I on peptide/protein purity for the strategic planning of ongoing Key Comparisons of the Protein Analysis Working Group (PAWG) within the Comité Consultatif pour la Quantité de Matière (CCQM). The assignment of the mass fraction content of high purity peptide/protein materials will be the subject of the CCQM-K115/P55.2 comparison series to directly support NMI services and certified reference materials currently being provided by NMIs. [ABSTRACT FROM AUTHOR]

White birch (Betula papyrifera) is a dominant tree species of the Boreal Forest. Recent studies have shown that it is fairly resistant to heavy metal contamination, specifically to nickel. Knowledge of regulation of genes associated with metal resistance in higher plants is very sketchy. Availability and annotation of the dwarf birch (B. nana) enables the use of high throughout sequencing approaches to understanding responses to environmental challenges in other Betula species such as B. papyrifera. The main objectives of this study are to 1) develop and characterize the B. papyrifera transcriptome, 2) assess gene expression dynamics of B. papyrifera in response to nickel stress, and 3) describe gene function based on ontology. Nickel resistant and susceptible genotypes were selected and used for transcriptome analysis. A total of 208,058 trinity genes were identified and were assembled to 275,545 total trinity transcripts. The transcripts were mapped to protein sequences and based on best match; we annotated the B. papyrifera genes and assigned gene ontology. In total, 215,700 transcripts were annotated and were compared to the published B. nana genome. Overall, a genomic match for 61% transcripts with the reference genome was found. Expression profiles were generated and 62,587 genes were found to be significantly differentially expressed among the nickel resistant, susceptible, and untreated libraries. The main nickel resistance mechanism in B. papyrifera is a downregulation of genes associated with translation (in ribosome), binding, and transporter activities. Five candidate genes associated to nickel resistance were identified. They include Glutathione S–transferase, thioredoxin family protein, putative transmembrane protein and two Nramp transporters. These genes could be useful for genetic engineering of birch trees. [ABSTRACT FROM AUTHOR]

Ongoing research is gradually broadening the idea of cancer treatment, with attention being focused on nanoparticles to improve the stability, therapeutic efficacy, targeting, and other important metrics of conventional drugs and traditional drug delivery methods. Studies have demonstrated that drug delivery carriers based on biomaterials (e.g., protein nanoparticles and lipids) and inorganic materials (e.g., metal nanoparticles) have potential anticancer effects. Among these carriers, self-assembled proteins and peptides, which are highly biocompatible and easy to standardize and produce, are strong candidates for the preparation of anticancer drugs. Breast cancer (BC) and cervical cancer (CC) are two of the most common and deadly cancers in women. These cancers not only threaten lives globally but also put a heavy burden on the healthcare system. Despite advances in medical care, the incidence of these two cancers, particularly CC, which is almost entirely preventable, continues to rise, and the mortality rate remains steady. Therefore, there is still a need for in-depth research on these two cancers to develop more targeted, efficacious, and safe therapies. This paper reviews the types of self-assembling proteins and peptides (e.g., ferritin, albumin, and virus-like particles) and natural products (e.g., soy and paclitaxel) commonly used in the treatment of BC and CC and describes the types of drugs that can be delivered using self-assembling proteins and peptides as carriers (e.g., siRNAs, DNA, plasmids, and mRNAs). The mechanisms (including self-assembly) by which the natural products act on CC and BC are discussed. The mechanism of action of natural products on CC and BC and the mechanism of action of self-assembled proteins and peptides have many similarities (e.g., NF-KB and Wnt). Thus, natural products using self-assembled proteins and peptides as carriers show potential for the treatment of BC and CC. [ABSTRACT FROM AUTHOR]

Interlayer spray is proposed as a convenient ionization source for direct analysis by mass spectrometry. Two slices of non-absorbent substrate hold the liquid sample to form a sandwich structure. By applying a high voltage to the sample, spray is generated at the tip of the substrate. The sampling procedure can be operated easily in an open condition and the spray is processed in a semi-enclosed condition, which leads to a relatively stable process. An ultralow amount (<2 μL) of the liquid sample can be analyzed without dilution, which ensures that the natural concentration and properties of the target are maintained. Less influence from the substrate is achieved compared with the spray methods based on porous absorbent materials, which results in a sensitivity enhancement of large molecule samples. It is demonstrated that the interlayer spray is applicable for the analysis of various compounds, including therapeutic drugs, peptides, and proteins. Good linearity can be obtained at a concentration as low as 50 ng/mL in the quantitative analysis for imatinib. We also show the ability to identify the chemical residuals on surfaces with high sensitivity by the 'wipe-spray' method, which is useful for the fast screening of illicit substances. Interlayer spray working with mass spectrometry provides a promising method for direct analysis in an ambient environment. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Cancer is one of the major diseases that seriously threaten human life. Traditional anticancer therapies have achieved remarkable efficacy but have also some unavoidable side effects. Therefore, more and more research focuses on highly effective and less-toxic anticancer substances of natural origin. Amphibian skin is rich in active substances such as biogenic amines, alkaloids, alcohols, esters, peptides, and proteins, which play a role in various aspects such as anti-inflammatory, immunomodulatory, and anticancer functions, and are one of the critical sources of anticancer substances. Currently, a range of natural anticancer substances are known from various amphibians. This paper aims to review the physicochemical properties, anticancer mechanisms, and potential applications of these peptides and proteins to advance the identification and therapeutic use of natural anticancer agents. [ABSTRACT FROM AUTHOR]

Obesity is a global health concern with limited treatment options due to side effects and limited efficacy. Bioactive peptides (BAPs) derived from food proteins have shown promise as safe and effective anti-obesity agents by regulating adipocyte differentiation through various signaling pathways. BAPs derived from milk, eggs, fish, and marine sources have been extensively studied for their anti-obesity effects in vitro and in vivo. These peptides can alter gut hormones and appetite to regulate energy balance while decreasing adipogenesis and increasing adipocyte apoptosis. This paper provides a comprehensive overview of the studies investigating the potency of BAPs in managing obesity. It focuses on their ability to modulate adipogenesis and regulate appetite and lipid metabolism. Key findings and Conclusions: BAPs derived from various food sources such as milk, eggs, fish, and marine byproducts have the potential to act as anti-obesity agents. These peptides have been shown to be able to regulate adipogenesis, lipid metabolism, and appetite control through different mechanisms, making them promising candidates for developing functional foods or nutraceuticals for obesity prevention and management. This paper also highlights the advantages of using BAPs over conventional anti-obesity drugs, such as their safety, natural origin, and lower risk of adverse effects. Further research and development in this field can lead to the identification and utilization of specific BAPs with optimized efficacy and minimal side effects, ultimately contributing to the development of novel anti-obesity therapies. [Display omitted] • Various food proteins as potential source of bioactive peptides is summarized. • Bioactive peptides derived from food is promising anti-obesity agent. • In vitro and in vivo experiment proven an anti-obesity activity through various mechanism. • Food derived bioactive peptides are prospective for development of functional foods or nutraceuticals. [ABSTRACT FROM AUTHOR]

We describe the construction and characterization of a novel membrane designed to allow proteins separated by gel electrophoresis (SDS-PAGE) to be detected as peptides by mass spectrometry in an efficient and comprehensive manner. The key attribute of the membrane is a bifunctional design that allows for the digestion of protein(s) and retention of the resulting peptides with minimal lateral diffusion. Silane chemistries are used to differentially treat the opposing surfaces of a glass filter paper to enable this unique capability. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department 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.)

Background: To assess the relationship of chosen salivary proteins and peptides levels with the occurrence of caries in children. Methods: PubMed, MEDLINE and EMBASE databases from 2000 to 2018 were researched for original observational studies published in English. The risk of bias and quality of the included papers were assessed regarding the guidelines by Fowkes and Fulton. Results: Twenty‐two studies were included in the review, from which the issue of glycoproteins (including immunoglobulins), AMPs and salivary enzymes was discussed. The research involved primary dentition (13 papers), as well as mixed (7) and permanent dentition (5). Caries assessment included visual inspection, dmft/s and DMFT/S indexed; quantity of Streptococcus mutans and Lactobacillus spp. bacteria; and caries risk assessment. Discussion: The results of studies regarding the connection between salivary peptides and proteins and caries development in children are promising; however, further investigations should be undertaken. The majority of studies included are case–control and cross‐sectional; however, it is necessary to conduct more cohort studies with adequate follow‐up prior to considering this as markers for caries risk assessment. [ABSTRACT FROM AUTHOR]

The transporter associated with antigen processing (TAP) is a key player in the major histocompatibility class I-restricted antigen presentation and an attractive target for immune evasion by viruses. Bovine herpesvirus 1 impairs TAP-dependent antigenic peptide transport through a two-pronged mechanism in which binding of the UL49.5 gene product to TAP both inhibits peptide transport and triggers its proteasomal degradation. How UL49.5 promotes TAP degradation has, so far, remained unknown. Here, we use high-content siRNA and genome-wide CRISPR-Cas9 screening to identify CLR2KLHDC3 as the E3 ligase responsible for UL49.5-triggered TAP disposal. We propose that the C terminus of UL49.5 mimics a C-end rule degron that recruits the E3 to TAP and engages the cullin-RING E3 ligase in endoplasmic reticulum-associated degradation. [ABSTRACT FROM AUTHOR]

Protein S-acylation is an important lipid modification characteristic for heterogeneity in the acyl chain and dynamicity in the acylation/deacylation cycle. Most S-acylproteomic research has been limited by indirect identification of modified proteins/peptides without attached fatty acids, resulting in the failure to precisely characterize S-acylated sites with attached fatty acids. The study of S-acylation turnover is still limited at the protein level. Herein, aiming to site-specifically profile both the heterogeneity and the turnover of S-acylation, we first developed a site-specific strategy for intact S-acylated peptide analysis by introducing an acid cleavable bioorthogonal tag into a metabolic labelling method (ssMLCC). The cleavable bioorthogonal tag allowed for the selective enrichment and efficient MS analysis of intact S-acylated peptides so that S-acylated sites and their attached fatty acids could be directly analysed, enabling the precise mapping of S-acylated sites, as well as circumventing false positives from previous studies. Moreover, 606 S-palmitoylated (C16:0) sites of 441 proteins in HeLa cells were identified. All types of S-acylated peptides were further characterized by an open search, providing site-specific profiling of acyl chain heterogeneity, including S-myristoylation, S-palmitoylation, S-palmitoleylation, and S-oleylation. Furthermore, site-specific monitoring of S-palmitoylation turnover was achieved by coupling with pulse-chase methods, facilitating the detailed observation of the dynamic event at each site in multi-palmitoylated proteins, and 85 rapidly cycling palmitoylated sites in 79 proteins were identified. This study provided a strategy for the precise and comprehensive analysis of protein S-acylation based on intact S-acylated peptide analysis, contributing to the further understanding of its complexity and biological functions. [ABSTRACT FROM AUTHOR]

This paper summarizes the early research results on studying proteins and peptides at interfaces using sum frequency generation (SFG) vibrational spectroscopy. SFG studies in the C—H stretching frequency region to examine the protein side-chain behavior and in the amide I frequency region to investigate the orientation and conformation of interfacial peptides/proteins are presented. The early chiral SFG research and SFG isotope labeling studies on interfacial peptides/proteins are also discussed. These early SFG studies demonstrate the feasibility of using SFG to elucidate interfacial molecular structures of peptides and proteins in situ, which built a foundation for later SFG investigations on peptides and proteins at interfaces. [ABSTRACT FROM AUTHOR]

Research investigating milk-derived proteins has brought to light the potential for their use as novel anticancer agents. This paper aims to systematically review studies examining the effectiveness of milk-derived proteins in the treatment of head and neck cancer. A systematic literature search of Medline, Evidence-Based Medicine, and Web of Science databases including papers published from all dates was completed. Inter-rater reliability was high during the title, abstract, and full-text screening phases. Inclusion criteria, exclusion criteria, and data extraction were based on the PICOS tool and research questions. Reporting followed the Preferred Reporting Items for Systematic Review and Meta-Analysis criteria. Eligible in vitro and in vivo studies (n = 8/658) evaluated lactoferrin, α-lactalbumin, and its complexes, such as HAMLET, BAMLET and lactalbumin-oleic acid complexes, as well as lactoperoxidase, whey, and casein. Their effectiveness in the treatment of head and neck cancer cells lines found that these compounds can inhibit tumour growth modulate cancer gene expression, and have cytotoxic effects on cancer cells. However, the exact mechanisms by which these effects are achieved are not well understood. Systematically designed, large, optimally controlled, collaborative studies, both in vitro and in vivo, will be required to gain a better understanding of their potential role in the treatment of head and neck cancer. [ABSTRACT FROM AUTHOR]

The paper is devoted to the problems of the life origin, the study of which was launched by the Academician E.M. Galimov. E.M. Galimov is a scientist with a wide range of research interests, a deep understanding of fundamental natural processes, a researcher with a remarkable intuition. Numerous considerations and discussions of one of the authors of the article, S.D. Varfolomeev with the Аcademician E.M. Galimov resulted in the formulation of a concept providing a natural-scientific explanation of the origin of life. The basic kinetic principles of the nucleation and evolution of protobiopolymeric molecules are considered. Our approach involves the processes of polymerization and selection of macromolecular structures and is based on thermocycle, which provides the thermodynamic possibility of the formation of a monomer–monomer bond and kinetic selection of structures through a choice of more statutory complexes. Kinetic modeling and analysis of obtained solutions demonstrated the possibility of exponential growth of all protopolymers of the system and the formation of possible interpolymer complexes representing the prototypes of ribosome-type cellular organelles. The possibility of the emergence of life having a fundamentally different chemical basis under nonterrestrial conditions is considered. [ABSTRACT FROM AUTHOR]

Diseases caused by bacterial infections become a critical problem in public heath. Antibiotic, the traditional treatment, gradually loses their effectiveness due to the resistance. Meanwhile, antibacterial proteins attract more attention because of broad spectrum and little harm to host cells. Therefore, exploring new effective antibacterial proteins is urgent and necessary. In this paper, we are committed to evaluating the effectiveness of ab-initio docking methods in antibacterial protein–protein docking. For this purpose, we constructed a three-dimensional (3D) structure dataset of antibacterial protein complex, called APCset, which contained |$19$| protein complexes whose receptors or ligands are homologous to antibacterial peptides from Antimicrobial Peptide Database. Then we selected five representative ab-initio protein–protein docking tools including ZDOCK3.0.2, FRODOCK3.0, ATTRACT, PatchDock and Rosetta to identify these complexes' structure, whose performance differences were obtained by analyzing from five aspects, including top/best pose, first hit, success rate, average hit count and running time. Finally, according to different requirements, we assessed and recommended relatively efficient protein–protein docking tools. In terms of computational efficiency and performance, ZDOCK was more suitable as preferred computational tool, with average running time of |$6.144$| minutes, average Fnat of best pose of |$0.953$| and average rank of best pose of |$4.158$|⁠. Meanwhile, ZDOCK still yielded better performance on Benchmark 5.0, which proved ZDOCK was effective in performing docking on large-scale dataset. Our survey can offer insights into the research on the treatment of bacterial infections by utilizing the appropriate docking methods. [ABSTRACT FROM AUTHOR]

Obtaining accurate representations of energy landscapes of biomolecules such as proteins and peptides is central to the study of their physicochemical properties and biological functions. Peptides are particularly interesting, as they exploit structural flexibility to modulate their biological function. Despite their small size, peptide modeling remains challenging due to the complexity of the energy landscape of such highly-flexible dynamic systems. Currently, only stochastic sampling-based methods can efficiently explore the conformational space of a peptide. In this paper, we suggest to combine two such methods to obtain a full characterization of energy landscapes of small yet flexible peptides. First, we propose a simplified version of the classical Basin Hopping algorithm to reveal low-energy regions in the landscape, and thus to identify the corresponding meta-stable structural states of a peptide. Then, we present several variants of a robotics-inspired algorithm, the Transition-based Rapidly-exploring Random Tree, to quickly determine transition path ensembles, as well as transition probabilities between meta-stable states. We demonstrate this combined approach on met-enkephalin. [ABSTRACT FROM PUBLISHER]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department 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.)

Peptide/protein quantitation using mass spectrometry (MS) is advantageous due to its high sensitivity. Traditional absolute peptide quantitation methods rely on making calibration curves using peptide standards or isotope-labelled peptide standards, which are expensive and take time to synthesize. A method which can eliminate the need for using standards would be beneficial. Recently, we developed coulometric mass spectrometry (CMS) which can be used to quantify peptides that are oxidizable (e.g., those containing tyrosine or tryptophan), without using peptide standard. The method is based on electrochemical oxidation of peptides followed by MS measurement of the oxidation yield. However, it cannot be directly used to quantify peptides without oxidizable residues. To extend this method for quantifying peptides/proteins in general, in this study, we adopted a derivatization strategy, in which a target peptide is first tagged with an electroactive reagent such as monocarboxymethylene blue NHS ester (MCMB-NHS ester), followed with quantitation by CMS. To illustrate the power of this method, we have analyzed peptides MG and RPPGFSPFR. The quantification error was less than 5%. Using RPPGFSPFR as an example, the quantitation sensitivity of the technique was found to be 0.25 pmol. Furthermore, we also used the strategy to quantify proteins cytochrome C and β-casein with an error of 2–26 %. [Display omitted] • Coulometric mass spectrometry (CMS) in combination with derivatization strategy can be used for absolute quantitation of peptides and proteins in general. • Our quantitation method reported in this paper does not require the use of standards or isotope-labelled standards. • Our quantitation method reported in this paper is applicable to peptides that are not electrochemically active. • The derivatization of peptide with methylene blue electrochemical tag allows the oxidation of peptides at a very low potential (0.2 V vs. Ag/AgCl), thus providing the method selectivity. [ABSTRACT FROM AUTHOR]

The evolution of the SARS-CoV2 coronavirus spike S-protein is studied using a mass spectrometry based protein phylogenetic approach. A study of a large dataset comprising sets of peptide masses derived from over 3000 proteins of the SARS-CoV2 virus shows that the approach is capable of resolving and correctly displaying the evolution of the major variants of concern. Using these numerical datasets, through a pairwise comparison of sets of proteolytic peptide masses for each protein, the tree is built without the need for the sequence data itself or any sequence alignment. In the same analysis, single point mutations are calculated from peptide mass differences of different protein sets and these are displayed at the branch nodes on the tree. The tree topology is found to be consistent with that generated using conventional sequence-based phylogenetics by a manual visualisation and using a tree comparison algorithm. The mass tree resolves major variants of the virus and displays non-synonymous mutations, calculated based on the mass data alone, on the tree that enable protein evolution to be charted and tracked along interconnected branches. Tracking the evolution of the SARS-CoV2 coronavirus S-protein is of particular importance given its role in the attachment of the virus to host cells ahead of viral replication. [ABSTRACT FROM AUTHOR]

In the past 20 years, the global per capita protein demand has been increasing year by year, and thus the search for sustainable and healthier alternative proteins is the focus of current food research. Yeast proteins are of microbial origin with environmentally friendly advantages. They are high-quality proteins with high bioavailability and are expected to be used as novel alternative proteins for food applications. Although reports on yeast extracts continue to increase, studies on the composition, production methods, and functional properties of yeast proteins lack systematic reviews. In addition, the application of yeast proteins in the food industry has not been summarized previously. This paper reviews the composition of yeast proteins and the approaches for their isolation and extraction, and systematically introduces the functional properties and the wide applications in food fields. Future perspectives for yeast proteins to sustainably and healthily meet the world's growing protein demand are also elucidated. Yeast proteins have great application potential as alternative proteins with a reasonable proportion of amino acid composition. Yeast proteins can be hydrolyzed to produce yeast peptides and can also be used as protein supplements, fining agents, meat extenders, etc. Overcoming the limitations of high nucleic acid content and high cost, and improving the functional properties and sensory acceptability of yeast proteins will greatly promote their market applications. This review will provide ideas and guidance for the research and development of yeast proteins in food applications. Yeast proteins have high nutritional value with an ideal amino acid composition and a wealth of functions and properties. The excellent characteristics allow yeast proteins to be used as sustainable alternative proteins in food applications. [Display omitted] • The compositions and extraction approaches of yeast proteins are overviewed. • The functional properties of yeast proteins are summarized. • The applications of yeast proteins as alternative proteins in food are reviewed. • The strategies to improve the utilization of yeast proteins are emphasized. [ABSTRACT FROM AUTHOR]

In the regime of domain classifications, the protein universe unveils a discrete set of folds connected by hierarchical relationships. Instead, at sub-domain-size resolution and because of physical constraints not necessarily requiring evolution to shape polypeptide chains, networks of protein motifs depict a continuous view that lies beyond the extent of hierarchical classification schemes. A number of studies, however, suggest that universal sub-sequences could be the descendants of peptides emerged in an ancient pre-biotic world. Should this be the case, evolutionary signals retained by structurally conserved motifs, along with hierarchical features of ancient domains, could sew relationships among folds that diverged beyond the point where homology is discernable. In view of the aforementioned, this paper provides a rationale where a network with hierarchical and continuous levels of the protein space, together with sequence profiles that probe the extent of sequence similarity and contacting residues that capture the transition from pre-biotic to domain world, has been used to explore relationships between ancient folds. Statistics of detected signals have been reported. As a result, an example of an emergent sub-network that makes sense from an evolutionary perspective, where conserved signals retrieved from the assessed protein space have been co-opted, has been discussed. [ABSTRACT FROM AUTHOR]

Featured Application: Proteins could be beneficial in their concentrated products or isolates, of which mem-brane-based filtration methods, such as ultrafiltration (UF), encompass application in broad spectra of protein sources. Proteins are one of the primary building blocks that have significant functional properties to be applied in food and pharmaceutical industries. Proteins could be beneficial in their concentrated products or isolates, of which membrane-based filtration methods such as ultrafiltration (UF) encompass application in broad spectra of protein sources. More importantly, selective enrichment by UF is of immense interest due to the presence of antinutrients that may dominate their perspicuous bioactivities. UF process is primarily obstructed by concentration polarization and fouling; in turn, a trade-off between productivity and selectivity emerges, especially when pure isolates are an ultimate goal. Several factors such as operating conditions and membrane equipment could leverage those pervasive contributions; therefore, UF protocols should be optimized for each unique protein mixture and mode of configuration. For instance, employing charged UF membranes or combining UF membranes with electrodialysis enables efficient separation of proteins with a similar molecular weight, which is hard to achieve by the conventional UF membrane. Meanwhile, some proposed strategies, such as utilizing ultrasonic waves, tuning operating conditions, and modifying membrane surfaces, can effectively mitigate fouling issues. A plethora of advancements in UF, from their membrane material modification to the arrangement of new configurations, contribute to the quest to actualize promising potentials of protein separation by UF, and they are reviewed in this paper. [ABSTRACT FROM AUTHOR]

Biothiols play essential roles in balancing the redox state and modulating cellular functions. Fluorescent probes for monitoring/labelling biothiols often suffer from slow reaction rates, strong background fluorescence and cytotoxic byproduct release. Thus, developing facile and versatile probes to overcome the challenges is still in high demand. Here, we report four coumarin–maleimides as fast responding and fluorogenic probes to detect GSH or label peptides/proteins. The probes quantitatively and selectively react with GSH via Michael addition within 1–2 min, achieving an 11–196-fold increase in fluorescence quantum yield via blockage of the photoinduced electron transfer (PET) process. Optimized probe 4 is applied for the detection of GSH in vitro (A549 cells) and in vivo (zebrafish embryos). Taking advantage of the fast Michael addition between the maleimide moiety and the sulfhydryl group, we expand the application of our method for fluorescent labelling of peptides/proteins and for tracking their cellular uptake process. The labelling strategy works for both Cys-bearing and Cys-free proteins after the introduction of a sulfhydryl group using Traut's reagent. Fluorescence assay reveals that the TAT-peptide can efficiently enter cells, but H3 protein, part of nucleosomes, prefers to bind on the cell membrane by electrostatic interactions, shedding light on the cellular uptake activity of nucleosomes and affording a potential membrane staining strategy. Overall, our study illustrates the broad potential of coumarin–maleimide based dual-functional probes for GSH detection and versatile protein labelling in biochemical research. [ABSTRACT FROM AUTHOR]

Peptides are gaining prominence in various fields, including the pharmaceutical industry. To meet regulatory requirements, they must achieve a certain purity threshold to ensure safe administration. Numerous purification technologies have been employed to purify peptides, aiming to reduce cost and time while being sustainable and efficient. These include chromatography, magnetic nanoparticles, isoelectric focusing, and membrane filtration. The physicochemical properties of peptides are the main driving element behind these technologies. While chromatographic separation remains the gold standard for peptide separation and purification, with various models to predict the elution behaviors of peptides, other technologies have demonstrated their capability to meet the performance of established chromatographic methodologies, with better productivity and reduced cost. This opens the door for further investigational studies to assess these outcomes and potentially introduce new techniques for peptide purification. In this review, we examine these technologies in terms of their efficiency and their ability to meet sustainability requirements, concluding with remarks and an outlook on future advancements. [ABSTRACT FROM AUTHOR]

Utilizing a novel approach known as aptamer-assisted phage display (APD), we identified an anti-PD-L1 peptide, NV Pep, capable of simultaneous binding to PD-L1 alongside the DNA aptamer MJ5C. Combined inhibition using NV Pep and MJ5C demonstrated significant enhancement compared to individual ligands against the PD-1/PD-L1 interaction. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office 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.)

We have earlier reported the iMOLSDOCK technique to perform ‘induced-fit’ peptide-protein docking. iMOLSDOCK uses the mutually orthogonal Latin squares (MOLSs) technique to sample the conformation and the docking pose of the small molecule ligand and also the flexible residues of the receptor protein, and arrive at the optimum pose and conformation. In this paper we report the extension carried out in iMOLSDOCK to dock nonpeptide small molecule ligands to receptor proteins. We have benchmarked and validated iMOLSDOCK with a dataset of 34 protein-ligand complexes as well as with Astex Diverse dataset, with nonpeptide small molecules as ligands. We have also compared iMOLSDOCK with other flexible receptor docking tools GOLD v5.2.1 and AutoDock Vina. The results obtained show that the method works better than these two algorithms, though it consumes more computer time. The source code and binary of MOLS 2.0 (under a GNU Lesser General Public License) are freely available for download at https://sourceforge.net/projects/mols2-0/files/. [ABSTRACT FROM AUTHOR]

Around us, we have many chiral macromolecules such as protein, carbohydrate, nucleic acid, steroids, peptides and phospholipids. Hence, these compounds exist in enantiomeric forms and we know that only one of the enantiomeric forms is important to us and another may or may not be useful. Therefore, chiral analysis of macromolecules has taken a unique place in analytical chemistry. The chiral separation of such macromolecules by analytical techniques is very difficult so only few papers were found in the literature, which has been discussed in this chapter. The presented chapter describes chiral analysis of macromolecule only by two analytical techniques i.e. high performance liquid chromatography and capillary electrophoresis. Besides, the efforts were made to discuss the future perspective regarding enantio-separation of such chiral macromolecules. [ABSTRACT FROM AUTHOR]

Rationale: Protein citrullination (deimination) is a post-translational modification of proteins converting arginine(s) into citrulline(s). "Overcitrullination" could be associated with severe pathological conditions. Mass spectrometric analysis of modified proteins is hindered by several problems. A comprehensive study of the fragmentation of deiminated peptides is not yet available. In this paper we have made an attempt to describe the characteristics of these processes, based on the studies of epitope model oligopeptides derived from clinically relevant proteins. Methods: Solutions of purified model peptides containing either one or two citrulline residues as well as their native variants were injected directly into the electrospray source of a high accuracy and resolution quadrupole-time-of-flight instrument and were analysed by tandem mass spectrometry using low-energy collision-induced dissociation. Results: Loss of isocyanic acid from citrulline residues is a preferred fragmentation route for deiminated peptides, which yields ornithine residues in the sequence. However, simultaneous detection of both the isocyanic acid loss and sequence fragments is often compromised. A preferential cleavage site was observed between citrulline and any other following amino acids yielding intensive complementary b- and y-type ions. Also, citrulline positioned at the C-termini displays a preferential cleavage N-terminal to this residue yielding characteristic y1 ions. These phenomena are described here for the first time and are referred to as the "citrulline effect". Conclusions: We found that the citrulline effect is very pronounced and could be used as a complementary tool for the confirmation of modification sites in addition to losses of isocyanic acids from the protonated molecules or from fragment ions. Low collision energy applied to peptide ions having partially mobile protons reveals the site of modification by generating specific and intensive fragments of the sequence. On the other hand, fragmenting precursor ions with mobile protons usually allows full sequence coverage, although citrulline-specific fragments may exhibit lower intensities compared to other fragments. [ABSTRACT FROM AUTHOR]

Memetic Algorithms are population-based metaheuristics intrinsically concerned with exploiting all available knowledge about the problem under study. The incorporation of problem domain knowledge is not an optional mechanism, but a fundamental feature of the Memetic Algorithms. In this paper, we present a Memetic Algorithm to tackle the three-dimensional protein structure prediction problem. The method uses a structured population and incorporates a Simulated Annealing algorithm as a local search strategy, as well as ad-hoc crossover and mutation operators to deal with the problem. It takes advantage of structural knowledge stored in the Protein Data Bank, by using an Angle Probability List that helps to reduce the search space and to guide the search strategy. The proposed algorithm was tested on 19 protein sequences of amino acid residues, and the results show the ability of the algorithm to find native-like protein structures. Experimental results have revealed that the proposed algorithm can find good solutions regarding root-mean-square deviation and global distance total score test in comparison with the experimental protein structures. We also show that our results are comparable in terms of folding organization with state-of-the-art prediction methods, corroborating the effectiveness of our proposal. [ABSTRACT FROM AUTHOR]

The protein structure refinement using conformational sampling is important in hitherto protein studies. In this paper, we examined the protein structure refinement by means of potential energy minimization using immune computing as a method of sampling conformations. The method was tested on the x-ray structure and 30 decoys of the mutant of [Leu]Enkephalin, a paradigmatic example of the biomolecular multiple-minima problem. In order to score the refined conformations, we used a standard potential energy function with the OPLSAA force field. The effectiveness of the search was assessed using a variety of methods. The robustness of sampling was checked by the energy yield function which measures quantitatively the number of the peptide decoys residing in an energetic funnel. Furthermore, the potential energy-dependent Pareto fronts were calculated to elucidate dissimilarities between peptide conformations and the native state as observed by x-ray crystallography. Our results showed that the probed potential energy landscape of [Leu]Enkephalin is self-similar on different metric scales and that the local potential energy minima of the peptide decoys are metastable, thus they can be refined to conformations whose potential energy is decreased by approximately [ABSTRACT FROM AUTHOR]

Beta amyloid ( \textA\beta ) peptide, which is a common neuropathological hallmark deposit in the brain of patients with Alzheimer’s disease, typically comprises 39–43 amino acid residues. \textA\beta peptides exist as isoforms of \textA\beta {\textsf {1-40}} and \textA\beta {\textsf {1-42}} with various lengths. In this research, atomic force microscopy (AFM) was applied to investigate \textA\beta {\textsf {1-40}} aggregations in Hank’s Balanced Salt Solution. Toxic effect of \textA\beta {\textsf {1-40}} oligomer was investigated in live SH-SY5Y neuroblastoma cells by characterizing cell morphology and cell mechanics using high-resolution AFM scanning. \textA\beta {\textsf {1-40}} oligomer-induced cytoskeleton reorganization was also observed under confocal microscopy, and it can account for reduction in Young’s modulus of cells. Meanwhile, phosphorylation of tau increased after \textA\beta {\textsf {1-40}} oligomer treatment, possibly resulting in microtubule disassembly. This paper demonstrates the linkage between cellular mechanical changes and neurodegeneration mediated by \textA\beta {\textsf {1-40}} . The method used implies promising applications of real-time monitoring of cellular mechanical properties given the toxic effects of \textA\beta {\textsf {1-40}} on living neuronal cells. [ABSTRACT FROM PUBLISHER]

Scabies is an infestation of the skin by the mite Sarcoptes scabiei. It manifests with pruritic erythematous papules and excoriations, in addition to the pathognomonic burrows. Multiple drugs can be used for treatment, but resistance to conventional therapy is increasing throughout the years. This paper will review the mechanisms of resistance proposed in the literature and some of the potential solutions to this problem. [ABSTRACT FROM AUTHOR]

Dirhodium complexes of general formula [Rh2(O2CR)4]L2 are a well-known class of bimetallic compounds that are used as efficient catalysts for a variety of reactions and have been shown to be potent antibacterial and anticancer agents. The catalytic and biological properties of these complexes largely depend on the nature of the bridging carboxylate ligands. Trifluoroacetate (tfa)-containing dirhodium compounds have been used to build artificial metalloenzymes upon reaction with peptides and have been shown to be more cytotoxic than dirhodium tetraacetate. However, there is no structural information on the interaction between these compounds and proteins. Here, cis-Rh2(μ-O2CCH3)2(μ-O2CCF3)2 ([cis-Rh2(OAc)2(tfa)2]) has been synthesized and its reaction with bovine pancreatic ribonuclease (RNase A) and hen egg white lysozyme (HEWL) was analyzed using a combination of different techniques, including Fluorine-19 nuclear magnetic resonance spectroscopy and macromolecular X-ray crystallography, with the aim to unveil the differences in the reactivity of tfa-containing dihrodium complexes with proteins when compared to [Rh2(OAc)4]. [cis-Rh2(OAc)2(tfa)2] and [Rh2(OAc)4] bind the N atoms of His side chains of RNase A at the axial position; however the fluorine-containing compound rapidly loses its tfa ligands, while [Rh2(OAc)4] can retain the acetate ligands upon protein binding. The reactivity of [cis-Rh2(OAc)2(tfa)2] with HEWL is slightly distinct when compared to that of [Rh2(OAc)4] under the same experimental conditions; however, both [cis-Rh2(OAc)2(tfa)2] and [Rh2(OAc)4] degrade when soaked within HEWL crystals. These results provide a structural-based guide for the design of new heterogenous chiral dirhodium/peptide and dirhodium/protein adducts with application in the fields of organic synthesis and asymmetric catalysis. [ABSTRACT FROM AUTHOR]

Cisplatin (CDDP) is a highly potent chemotherapy drug. But its nephrotoxicity poses a significant limitation to its use. The renin-angiotensin system (RAS) has been proposed to play a role in drug-induced nephrotoxicity. This systematic review (SR) sought to identify the link between CDDP-induced nephrotoxicity and the RAS pathway. In this SR, relevant keywords were employed to explore databases such as PubMed (MEDLINE), Scopus (Elsevier), and Institute for Scientific Information (ISI) Web of Science up to October 2023. Nine studies were selected based on predefined inclusion/exclusion criteria. The findings support the involvement of the RAS in the CDDP-induced nephrotoxicity model, along with the activation of inflammatory mediators, lipid peroxidation, and changes in markers of kidney tissue damage. Furthermore, physiology and pathology of RAS-related interventions in CDDP-induced nephrotoxicity models have involved the factors such as human organic cation transporter 2 (hOCT2), organic anion transporting polypeptides 1B1 (OATP1B1) and 1B3, kallikrein-kinin system, and bradykinin receptors. CDDP-induced nephrotoxicity has been found to be substantially influenced by both classic and nonclassic RAS axes. Angiotensin II exacerbates renal damage induced by CDDP. Conversely, inhibiting the pressor arm of RAS in males mitigates this damage. However, activation of the renal vasodepressor arm of RAS exacerbates CDDP-induced nephrotoxicity in females. These findings underscore gender differences in renal function and response to RAS-related interventions in the presence of CDDP. This SR provides insights into both beneficial and adverse interventions associated with RAS in the CDDP-induced nephrotoxicity, offering valuable considerations for researchers and clinicians. [ABSTRACT FROM AUTHOR]

The involvement of the Signal peptide-complement components of C1r/C1s, the sea urchin Uegf and Bone Morphogenetic Protein (CUB) domain-Epidermal Growth Factor (EGF)-related (SCUBE) gene in human diseases has been progressively apparent. The SCUBE1 is detectable in platelet-aggregation diseases. The SCUBE2 is reported to have a better cancer survival prognosis. However, SCUBE3 is detected in bone-related diseases. SCUBE gene interacts with Hedgehog (Hh) signaling pathway and epidermal growth factor receptor (EGFR), which has a wide range of biological functions such as cell proliferation, apoptosis, differentiation, and activation of platelet activity. The current review is a systematic review performed using SCOPUS, Cochrane, and Pubmed/Medline according to The Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P) guidelines. This review discusses the entanglement of the SCUBE gene's potential role in human diseases. Examining the role of the SCUBE family sheds new light on platelet aggregation-related diseases, cancer prognosis, and their pathogenesis. [ABSTRACT FROM AUTHOR]

Spike protein sequences in SARS-CoV-2 have been employed for vaccine epitopes, but many short constituent sequences (SCSs) in the spike protein are present in the human proteome, suggesting that some anti-spike antibodies induced by infection or vaccination may be autoantibodies against human proteins. To evaluate this possibility of "molecular mimicry" in silico and in vitro, we exhaustively identified common SCSs (cSCSs) found both in spike and human proteins bioinformatically. The commonality of SCSs between the two systems seemed to be coincidental, and only some cSCSs were likely to be relevant to potential self-epitopes based on three-dimensional information. Among three antibodies raised against cSCS-containing spike peptides, only the antibody against EPLDVL showed high affinity for the spike protein and reacted with an EPLDVL-containing peptide from the human unc-80 homolog protein. Western blot analysis revealed that this antibody also reacted with several human proteins expressed mainly in the small intestine, ovary, and stomach. Taken together, these results showed that most cSCSs are likely incapable of inducing autoantibodies but that at least EPLDVL functions as a self-epitope, suggesting a serious possibility of infection-induced or vaccine-induced autoantibodies in humans. High-risk cSCSs, including EPLDVL, should be excluded from vaccine epitopes to prevent potential autoimmune disorders. [ABSTRACT FROM AUTHOR]

Coffee silverskin (CS), a by-product of the coffee roasting process, has high protein content (16.2−19.0%, w/w), making it a potential source for plant protein and bioactive peptide production. This study aims to develop innovative extraction methods for phenolic compounds and proteins from CS. The conditions for hydrothermal (HT) extraction of phenolic compounds from CS were optimized by varying CS loading (2.5−10%, w/v), temperature (110−130 °C), and time (5−30 min) using a one-factor-at-a-time (OFAT) approach. The highest TPC of 55.59 ± 0.12 µmole GAE/g CS was achieved at 5.0% (w/v) CS loading and autoclaving at 125 °C for 25 min. Following hydrothermal extraction, CS protein was extracted from HT-extracted solid fraction by microwave-assisted alkaline extraction (MAE) using 0.2 M NaOH at 90 W for 2 min, resulting in a protein recovery of 12.19 ± 0.39 mg/g CS. The CS protein was then subjected to enzymatic hydrolysis using protease from Bacillus halodurans SE5 (protease_SE5). Protease_SE5-derived CS protein hydrolysate had a peptide concentration of 0.73 ± 0.09 mg/mL, with ABTS, DPPH, and FRAP values of 15.71 ± 0.10, 16.63 ± 0.061, and 6.48 ± 0.01 µmole TE/mL, respectively. Peptide identification by LC-MS/MS revealed several promising biological activities without toxicity or allergenicity concerns. This study's integrated approach offers a sustainable and efficient method for extracting valuable compounds from CS, with potential applications in the food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Regulatory arrest peptides interact with specific residues on bacterial ribosomes and arrest their own translation. Here, we analyse over 30,000 bacterial genome sequences to identify additional Sec/YidC-related arrest peptides, followed by in vivo and in vitro analyses. We find that Sec/YidC-related arrest peptides show patchy, but widespread, phylogenetic distribution throughout the bacterial domain. Several of the identified peptides contain distinct conserved sequences near the C-termini, but are still able to efficiently stall bacterial ribosomes in vitro and in vivo. In addition, we identify many arrest peptides that share an R-A-P-P-like sequence, suggesting that this sequence might serve as a common evolutionary seed to overcome ribosomal structural differences across species. Regulatory arrest peptides interact with the bacterial ribosome to halt their own translation. Here, Fujiwara et al. analyse thousands of bacterial genome sequences and identify additional arrest peptides, revealing sequence diversity and patchy, but widespread, distribution across the bacterial domain. [ABSTRACT FROM AUTHOR]

In peptite mass fingerprinting, an unknown protein is fragmented into smaller peptides whose masses are accurately measured; the obtained list of weights is then compared with a reference database to obtain a set of matching proteins. The exponential growth of known proteins discourage the use of brute force methods, where the weights’ list is compared with each protein in the reference collection; luckily, the scientific literature in the database field highlights that well designed searching algorithms, coupled with a proper data organization, allow to quickly solve the identification problem even on standard desktop computers. In this paper, IsAProteinsDB, an indexed database of trypsinized proteins, is presented. The corresponding search algorithm shows a time complexity that does not significantly depends on the size of the reference protein database. [ABSTRACT FROM PUBLISHER]

Background: The characterization of protein-peptide interactions is a challenge for computational molecular docking. Protein-peptide docking tools face at least two major difficulties: (1) efficient sampling of large-scale conformational changes induced by binding and (2) selection of the best models from a large set of predicted structures. In this paper, we merge an efficient sampling technique with external information about side-chain contacts to sample and select the best possible models.Methods: In this paper we test a new protocol that uses information about side-chain contacts in CABS-dock protein-peptide docking. As shown in our recent studies, CABS-dock enables efficient modeling of large-scale conformational changes without knowledge about the binding site. However, the resulting set of binding sites and poses is in many cases highly diverse and difficult to score.Results: As we demonstrate here, information about a single side-chain contact can significantly improve the prediction accuracy. Importantly, the imposed constraints for side-chain contacts are quite soft. Therefore, the developed protocol does not require precise contact information and ensures large-scale peptide flexibility in the broad contact area.Conclusions: The demonstrated protocol provides the extension of the CABS-dock method that can be practically used in the structure prediction of protein-peptide complexes guided by the knowledge of the binding interface. [ABSTRACT FROM AUTHOR]

Background: Pregnant women exposed to Plasmodium falciparum generate antibodies against VAR2CSA, the parasite protein that mediates adhesion of infected erythrocytes to the placenta. There is a need of high-throughput tools to determine the fine specificity of these antibodies that can be used to identify immune correlates of protection and exposure. Here we aimed at developing a multiplex-immunoassay to detect antibodies against VAR2CSA antigens. Methods and findings: We constructed two multiplex-bead arrays, one composed of 3 VAR2CSA recombinant-domains (DBL3X, DBL5Ɛ and DBL6Ɛ) and another composed of 46 new peptides covering VAR2CSA conserved and semi-conserved regions. IgG reactivity was similar in multiplexed and singleplexed determinations (Pearson correlation, protein array: R2 = 0.99 and peptide array: R2 = 0.87). IgG recognition of 25 out of 46 peptides and all recombinant-domains was higher in pregnant Mozambican women (n = 106) than in Mozambican men (n = 102) and Spanish individuals (n = 101; p<0.05). Agreement of IgG levels detected in cryopreserved plasma and in elutions from dried blood spots was good after exclusion of inappropriate filter papers. Under heterogeneous levels of exposure to malaria, similar seropositivity cutoffs were obtained using finite mixture models applied to antibodies measured on pregnant Mozambican women and average of antibodies measured on pregnant Spanish women never exposed to malaria. The application of the multiplex-bead array developed here, allowed the assessment of higher IgG levels and seroprevalences against VAR2CSA-derived antigens in women pregnant during 2003–2005 than during 2010–2012, in accordance with the levels of malaria transmission reported for these years in Mozambique. Conclusions: The multiplex bead-based immunoassay to detect antibodies against selected 25 VAR2CSA new-peptides and recombinant-domains was successfully implemented. Analysis of field samples showed that responses were specific among pregnant women and dependent on the level of exposure to malaria. This platform provides a high-throughput approach to investigating correlates of protection and identifying serological markers of exposure for malaria in pregnancy. [ABSTRACT FROM AUTHOR]

The novel coronavirus (COVID-19) infections have adopted the shape of a global pandemic now, demanding an urgent vaccine design. The current work reports contriving an anti-coronavirus peptide scanner tool to discern anti-coronavirus targets in the embodiment of peptides. The proffered CoronaPep tool features the fast fingerprinting of the anti-coronavirus target serving supreme prominence in the current bioinformatics research. The anti-coronavirus target protein sequences reported from the current outbreak are scanned against the anti-coronavirus target data-sets via CORONAPEP which provides precision-based anti-coronavirus peptides. This tool is specifically for the coronavirus data, which can predict peptides from the whole genome, or a gene or protein's list. Besides it is relatively fast, accurate, userfriendly and can generate maximum output from the limited information. The availability of tools like CORONAPEP will immeasurably perquisite researchers in the discipline of oncology and structure-based drug design. [ABSTRACT FROM AUTHOR]

Proteins and peptides are amongst the most widely used research reagents but often their quality is inadequate and can result in poor data reproducibility. Here we propose a simple set of guidelines that, when correctly applied to protein reagents should provide more reliable experimental data. [ABSTRACT FROM AUTHOR]

Ubiquitination, catalyzed usually by a three-enzyme cascade (E1, E2, E3), regulates various eukaryotic cellular processes. E3 ligases are the most critical components of this catalytic cascade, determining both substrate specificity and polyubiquitination linkage specificity. Here, we reveal the mechanism of a naturally occurring E3-independent ubiquitination reaction of a unique human E2 enzyme UBE2E1 by solving the structure of UBE2E1 in complex with substrate SETDB1-derived peptide. Guided by this peptide sequence-dependent ubiquitination mechanism, we developed an E3-free enzymatic strategy SUE1 (sequence-dependent ubiquitination using UBE2E1) to efficiently generate ubiquitinated proteins with customized ubiquitinated sites, ubiquitin chain linkages and lengths. Notably, this strategy can also be used to generate site-specific branched ubiquitin chains or even NEDD8-modified proteins. Our work not only deepens the understanding of how an E3-free substrate ubiquitination reaction occurs in human cells, but also provides a practical approach for obtaining ubiquitinated proteins to dissect the biochemical functions of ubiquitination. Ubiquitin E3 ligases are key to accessing ubiquitinated proteins, but only a few substrates have defined E3 ligases. Here, the authors reveal the mechanism of naturally occurring E3-independent ubiquitination and develop an E3-free enzymatic strategy for the versatile generation of ubiquitinated proteins. [ABSTRACT FROM AUTHOR]

Tuna protein serves as a significant source of bioactive peptides, and its functional properties can be elucidated through predictive modeling, followed by experimental validation. In this study, the active polypeptides were obtained from tuna protein via enzymatic hydrolysis (TPP), and their peptide sequences were determined. Furthermore, the potential activity of these peptides was predicted, focusing on antioxidant peptides, and compared to the sequence library of known antioxidant peptides to identify common structural motifs. The accuracy of the prediction results was confirmed through in vitro antioxidant assays and molecular docking studies. We identified seven specific peptide segments derived from tuna protein that exhibit antioxidant potential, accounting for approximately 15% of all active peptides. Molecular docking and cell experiments were employed to provide compelling evidence for the presence of antioxidant peptides within tuna protein. This study not only lays a solid foundation for studying the structure of active peptides but also opens up a novel avenue for an expedited assessment of their properties. [ABSTRACT FROM AUTHOR]

Impedimetric biosensors represent a powerful and promising tool for studying and monitoring biological processes associated with proteins and can contribute to the development of new approaches in the diagnosis and treatment of diseases. The basic principles, analytical methods, and applications of hybrid impedimetric biosensors for express protein detection in biological fluids are described. The advantages of this type of biosensors, such as simplicity and speed of operation, sensitivity and selectivity of analysis, cost-effectiveness, and an ability to be integrated into hybrid microfluidic systems, are demonstrated. Current challenges and development prospects in this area are analyzed. They include (a) the selection of materials for electrodes and formation of nanostructures on their surface; (b) the development of efficient methods for biorecognition elements' deposition on the electrodes' surface, providing the specificity and sensitivity of biosensing; (c) the reducing of nonspecific binding and interference, which could affect specificity; (d) adapting biosensors to real samples and conditions of operation; (e) expanding the range of detected proteins; and, finally, (f) the development of biosensor integration into large microanalytical system technologies. This review could be useful for researchers working in the field of impedimetric biosensors for protein detection, as well as for those interested in the application of this type of biosensor in biomedical diagnostics. [ABSTRACT FROM AUTHOR]

The assembly line biosynthesis of the powerful anticancer‐antiviral didemnin cyclic peptides is proposed to follow a prodrug release mechanism in Tristella bacteria. This strategy commences with the formation of N‐terminal prodrug scaffolds and culminates in their cleavage during the cellular export of the mature products. In this study, a comprehensive exploration of the genetic and biochemical aspects of the enzymes responsible for both the assembly and cleavage of the acylated peptide prodrug scaffolds is provided. This process involves the assembly of N‐acyl‐polyglutamine moieties orchestrated by the nonribosomal peptide synthetase DidA and the cleavage of these components at the post‐assembly stage by DidK, a transmembrane CAAX hydrolase homolog. The findings not only shed light on the complex prodrug mechanism that underlies the synthesis and secretion of didemnin compounds but also offer novel insights into the expanded role of CAAX hydrolases in microbes. Furthermore, this knowledge can be leveraged for the strategic design of genome mining approaches aimed at discovering new bioactive natural products that employ similar prodrug biochemical strategies. [ABSTRACT FROM AUTHOR]

The elaboration of potent delivery systems for peptides/proteins is still a challenge but is increasingly needed in advanced therapy. In the present research, we have developed a nanoencapsulation system for peptides/proteins, which is suitable for the delivery of hydrophilic bioactive compounds. The preparation method combines the advantageous properties of reverse nanoemulsion and nanoprecipitation, resulting in the formation of nanoparticles in the size range of 350–500 nm. The polymeric coating composed of polycaprolactone allows chemical functionalization and protection while the inner microenvironment (containing 1-decanoyl-rac-glycerol and N,N-dimethyldodecylamine N-oxide surfactants) provides aqueous surrounding for the active with structural fidelity. Hen egg white lysozyme and β-lactoglobulin were successfully encapsulated, achieving protein contents of 10–60 μg/mg and encapsulation efficiencies ranging from 5–50% depending on the protein type and loading concentration. In vitro release measurement showed a biphasic sustained release profile of both proteins in the time range of one month. In vitro cytotoxicity investigation of protein-loaded nanoparticles exhibited good cell viability (above 95% at the highest treatment concentration of 0.3 mg/ml). The encapsulated membrane-active peptides have shown improved bioactivity. [ABSTRACT FROM AUTHOR]