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Objective: The bone conduction implant (BCI) 602 is a new transcutaneous BCI with smaller dimensions. However, limited patient numbers restrict the statistical power and generalizability of the current studies. The present systematic review and meta‐analysis summarize early audiological and medical outcomes of adult and pediatric patients implanted with the BCI 602 due to mixed or conductive hearing loss. Data Source: Following the Preferred Reporting items for Systematic Reviews and Meta‐analyses guidelines, 108 studies were reviewed, and 6 (5.6%) were included in the meta‐analysis. Review Method: The data on study and patient characteristics, surgical outcomes, and audiological test results were extracted from each article. Meta‐analysis employed the fixed‐effect and random‐effects models to analyze the mean differences (MDs) between pre‐ and postoperative performances. Results: In total, 116 patients were evaluated, including 64 (55%) adult and 52 (45%) pediatric patients. No intraoperative adverse events were reported, while postoperative complications were reported in 2 (3.1%) adult and 2 (3.8%) pediatric patients. Studies consistently showed significant improvements in audiological outcomes, quality of life, and sound localization in the aided condition. In the meta‐analysis, we observed a significant difference in the unaided compared to the aided condition in sound field thresholds (n = 112; MD, −27.05 dB; P < 0.01), signal‐to‐noise ratio (n = 96; MD, −6.35 dB; P < 0.01), and word recognition scores (n = 96; MD, 68.89%; P < 0.01). Conclusion: The implantation of the BCI 602 was associated with minimal surgical complications and excellent audiological outcomes for both the pediatric and the adult cohort. Therefore, our analysis indicates a high level of safety and reliability. Further research should focus on direct comparisons with other BCIs and long‐term functional outcomes. [ABSTRACT FROM AUTHOR]

We recently reported that the transketolase from Geobacillus stearothermophilus (TKgst) upon acyl transfer to nitrosoarenes generates N‐aryl hydroxamic acids (HA). The latter are metal chelating compounds that in the presence of Fe(III) ions form deep‐red complexes. Here, we applied this principle to the development of a colorimetric assay in both solid‐ and liquid‐phase formats for the high‐throughput screening of TKgst and its variants. Screening a set of positive hits from a L382X/D470X library validated the specificity and sensitivity of the assays. The solid surface assay allows a clear distinction between positive and negative colonies by the naked eye in qualitative mode, and further also to measure activity in semi‐quantitative fashion in the liquid‐phase format. The assay will be important for engineering the TKgst enzyme towards improved conversion of aromatic aldehydes by their close structural analogy to nitrosoarenes. [ABSTRACT FROM AUTHOR]

Objective: Recently, the Bonebridge 602 implant was introduced. Its smaller dimensions facilitate implantation even in surgically demanding cases. However, in extreme anatomical conditions, implant lifts are still required. We intended to report on the medical and audiological outcomes of all patients implanted with the implant with a secondary focus on the safety, efficacy, and feasibility of the use of 1‐mm lifts. Study Design: Retrospective cohort study. Setting: Tertiary academic center. Methods: We retrospectively analyzed all patients implanted with the Bonebridge 602. Patient demographics and surgically‐specific data were collected from the medical charts. Furthermore, audiological results were assessed. Outcomes were compared between implantations with versus without lifts. Results: Twenty‐one devices were implanted during the study period. Satisfactory audiological results were observed, while no intra‐ or postoperative adverse events occurred. The majority of patients were daily users at the end of the observation period (n = 20/21, 95.2%), and one patient (n = 1/21, 4.8%) was a nonuser after 6 months of use because of subjective dissatisfaction. Due to anatomical considerations, 1‐mm lifts were used in 4 implantations (19.0%). The application of lifts did not result in prolonged surgical times, complications, or shorter time of use, nor did it negatively affect audiometric results. Conclusion: Implantations with the new and smaller Bonebridge were associated with gratifying medical and audiological outcomes. Still, in extreme anatomical conditions, 1‐mm lifts are necessary. Nonetheless, surgical placement with the help of lifts seems safe, effective, and feasible, and is a viable option in cases with challenging anatomies due to previous surgeries or anomalies. [ABSTRACT FROM AUTHOR]

Two‐dimensional oxide films are potentially useful for future technological applications, but also important objects to study model catalyst systems on the more fundamental side. Here we study silica, germania, and mixed silica‐germania films supported on a metal single crystal surface Ru(0001). Those mixed films are interesting objects to systematically modify the properties of silica films, which may be used as membranes or covers for model studies in confined space, due to the modification of the rather stiff silica layers by incorporating germanium atoms replacing silicon atoms. Here we report a combined experimental and theoretical study of such layers, where we show how X‐ray photoelectron spectroscopy in combination with LEED and I/V LEEM measurements allow us to judge the formation of such mixed films. [ABSTRACT FROM AUTHOR]

eIF3, whose subunits are frequently overexpressed in cancer, regulates mRNA translation from initiation to termination, but mRNA‐selective functions of individual subunits remain poorly defined. Using multiomic profiling upon acute depletion of eIF3 subunits, we observed that while eIF3a, b, e, and f markedly differed in their impact on eIF3 holo‐complex formation and translation, they were each required for cancer cell proliferation and tumor growth. Remarkably, eIF3k showed the opposite pattern with depletion promoting global translation, cell proliferation, tumor growth, and stress resistance through repressing the synthesis of ribosomal proteins, especially RPS15A. Whereas ectopic expression of RPS15A mimicked the anabolic effects of eIF3k depletion, disruption of eIF3 binding to the 5′‐UTR of RSP15A mRNA negated them. eIF3k and eIF3l are selectively downregulated in response to endoplasmic reticulum and oxidative stress. Supported by mathematical modeling, our data uncover eIF3k‐l as a mRNA‐specific module which, through controlling RPS15A translation, serves as a rheostat of ribosome content, possibly to secure spare translational capacity that can be mobilized during stress. Are there mRNA‐selective functions of individual eIF3 subunits? Here, multiomic profiling upon acute depletion of eIF3 subunits uncovers eIF3k‐l as an mRNA‐specific module that serves as a rheostat of ribosome content, securing spare translational capacity that can be mobilized during stress. Acute depletion of eIF3 subunits has subunit‐selective impact on holo‐eIF3 architecture.eIF3k depletion uniquely causes increased tumor growth and ribosome content.eIF3k depletion boosts the translation of RPS15A mRNA through an eIF3‐binding site in the 5′‐UTR.eIF3k and eIF3l are selectively downregulated by cellular stress, thus promoting cell survival. [ABSTRACT FROM AUTHOR]

Purpose: To identify correlations between the vascular characteristics of macular neovascularization (MNV) obtained by optical coherence tomography angiography (OCTA) and distinct retinal fluid volumes in neovascular age‐related macular degeneration (nAMD). Methods: In this prospective interventional study, 54 patients with treatment‐naïve type 1 or 2 nAMD were included and treated with intravitreal aflibercept. At baseline and month 1, each patient underwent a SD‐OCT volume scan and volumetric flow scan using a swept‐source OCTA. A deep learning algorithm was used to automatically detect and quantify fluid in OCT scans. Angio Tool, a National Cancer Institute algorithm, was used to skeletonize MNV properties and quantify lesion size (LS), vessel area (VA), vessel density (VD), total number of endpoints (TNE), total number of junctions (TNJ), junction density (JD), total vessel length (TVL), average vessel length (AVL) and mean‐e‐lacunarity (MEL). Subsequently, linear regression models were used to investigate a correlation between OCTA parameters and fluid quantifications. Results: The median amount of fluid within the central 6‐mm EDTRS ring was 173.7 nl at baseline, consisting of 156.6 nl of subretinal fluid (SRF) and 2.3 nl of intraretinal fluid (IRF). Fluid decreased significantly in all compartments to 1.76 nl (SRF) and 0.64 nl (IRF). The investigated MNV parameters did not change significantly after the first treatment. There was no significant correlation between MNV parameters and relative fluid decrease after anti‐VEGF treatment. Baseline fluid correlated statistically significant but weakly with TNE (p = 0.002, R2 = 0.17), SRF with TVL (p = 0.04, R2 = 0.08), VD (p = 0.046, R2 = 0.08), TNE (p = 0.001, R2 = 0.20) and LS (p = 0.033, R2 = 0.09). IRF correlated with VA (p = 0.042, R2 = 0.08).The amount of IRF at month 1 correlated significantly but weakly with VD (p = 0.036, R2 = 0.08), JD (p = 0.019, R2 = 0.10) and MEL (p = 0.005, R2 = 0.14). Conclusion: Macular neovascularization parameters at baseline and month 1 played only a minor role in the exudation process in nAMD. None of the MNV parameters were correlated with the treatment response. [ABSTRACT FROM AUTHOR]

Background: DFNB28, a recessively inherited nonsyndromic form of deafness in humans, is caused by mutations in the TRIOBP gene (MIM #609761) on chromosome 22q13. Its protein TRIOBP helps to tightly bundle F‐actin filaments, forming a rootlet that penetrates through the cuticular plate into the cochlear hair cell body. Repeat motifs R1 and R2, located in exon 7 of the TRIOBP‐5 isoform, are the actin‐binding domains. Deletion of both repeat motifs R1 and R2 results in complete disruption of both actin‐binding and bundling activities, whereas deletion of the R2 motif alone retains F‐actin bundling ability in stereocilia rootlets. Methods: Target sequencing, using a custom capture panel of 180 known and candidate genes associated with sensorineural hearing loss, bioinformatics processing, and data analysis were performed. Genesis 2.0 was used for variant filtering based on quality/score read depth and minor allele frequency (MAF) thresholds of 0.005 for recessive NSHL, as reported in population‐based sequencing databases. All variants were reclassified based on the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP) guidelines together with other variant interpretation guidelines for genetic hearing loss. Candidate variants were confirmed via Sanger sequencing according to standard protocols, using the ABIPRISM 3730 DNA Analyzer. DNA sequence analysis was performed with DNASTAR Lasergene software. Results: Candidate TRIOBP variants identified among 94 indigenous sub‐Saharan African individuals were characterized through segregation analysis. Family TS005 carrying variants c.572delC, p.Pro191Argfs*50, and c.3510_3513dupTGCA, p.Pro1172Cysfs*13, demonstrated perfect cosegregation with the deafness phenotype. On the other hand, variants c.505C > A p.Asp168Glu and c.3636 T > A p.Leu1212Gln in the same family did not segregate with deafness and we have classified these variants as benign. A control family, TS067, carrying variants c.2532G > T p.Leu844Arg, c.2590C > A p.Asn867Lys, c.3484C > T p.Pro1161Leu, and c.3621 T > C p.Phe1187Leu demonstrated no cosegregation allowing us to classify these variants as benign. Together with published TRIOBP variants, the results showed that genotypes combining two truncating TRIOBP variants affecting repeat motifs R1 and R2 or R2 alone lead to a deafness phenotype, while a truncating variant affecting repeat motifs R1 and R2 or R2 alone combined with a missense variant does not. Homozygous truncating variants affecting repeat motif R2 cosegregate with the deafness phenotype. Conclusion: While a single intact R1 motif may be adequate for actin‐binding and bundling in the stereocilia of cochlear hair cells, our findings indicate that a truncated R2 motif in cis seems to be incompatible with normal hearing, either by interfering with the function of an intact R1 motif or through another as yet unknown mechanism. Our study also suggests that most heterozygous missense variants involving exon 7 are likely to be tolerated. [ABSTRACT FROM AUTHOR]

ATAs engineered for having an enlarged small binding pocket were applied for the synthesis of enantiomerically pure (R)‐benzo[1,3]dioxol‐5‐yl‐butylamine, a chiral component of human leukocyte elastase inhibitor DMP 777 (L‐694,458). Kinetic resolution of the racemic amine was performed by using the L59A variant of the (S)‐selective ATA from Chromobacterium violaceum (Cv‐ATA), providing the residual (R)‐enantiomer in excellent yield and >99% ee. At moderate enzyme loading and absence of co‐solvent, high volumetric productivity of 0.22 mol L−1 h−1 (42.5 g L−1 h−1) was achieved. Complementarily, the (S)‐enantiomer was generated via kinetic resolution using the (R)‐selective ATA‐117‐Rd11 from Arthrobacter sp. with acetone as the amino acceptor. In an alternative approach, we employed ATA‐117‐Rd11 for the asymmetric amination of the prochiral ketone precursor, which at 86% conversion gave the (R)‐benzo[1,3]dioxol‐5‐yl‐butylamine with excellent >99% ee. We further evaluated the utility of Cv‐ATA L59A for the asymmetric synthesis of pharmaceutically relevant (S)‐1‐phenylbutan‐1‐amine, a chiral component of the deubiquitinase inhibitor degrasyn (WP1130). The enzyme showed good tolerance to high concentrations of isopropylamine, producing (S)‐1‐phenylbutan‐1‐amine in enantiomerically pure form (>99% ee). [ABSTRACT FROM AUTHOR]

Cochlear implant, minimally invasive surgery, robotic cochlear implant surgery, image-guided surgery, keyhole access Adaption of the planning procedure by increasing the milling depth enables robotic cochlear implant surgery in ossified basal cochlear turns. Keywords: cochlear implant; image-guided surgery; keyhole access; minimally invasive surgery; robotic cochlear implant surgery EN cochlear implant image-guided surgery keyhole access minimally invasive surgery robotic cochlear implant surgery 504 507 4 04/22/22 20220501 NES 220501 Key Points Robotic cochlear implant surgery is a new and safe technique. Current challenges in robotic CI surgery include prolonged duration of the surgery compared to conventional techniques and exclusion of children. [Extracted from the article]

Hydroxamic acids are metal‐chelating compounds that show important biological activity including anti‐tumor effects. We have recently engineered the transketolase from Geobacillus stearothermopilus (TKgst) to convert benzaldehyde as a non‐natural acceptor substrate. Realizing the structural and electronic similarity to nitrosobenzene, we studied the TK‐catalyzed conversion of nitrosoarenes to yield N‐arylated hydroxamic acids. Here we demonstrate that wild‐type and variants of this versatile TKgst enzyme indeed induce the rapid biocatalytic conversion of variously p‐, m‐ and o‐substituted nitrosoarenes to produce a variety of corresponding N‐aryl hydroxamic acids via creation of a carbon‐nitrogen instead of a carbon‐carbon bond. Further structural modifications can be introduced by varying the donor component, such as hydroxypyruvate or pyruvate. [ABSTRACT FROM AUTHOR]

Finding new, safe strategies to prevent and control rheumatoid arthritis is an urgent task. Bioactive peptides and peptide‐rich protein hydrolyzate represent a new trend in the development of functional foods and nutraceuticals. The resulting tissue hydrolyzate of the chicken embryo (CETH) has been evaluated for acute toxicity and tested against chronic arthritis induced by Freund's full adjuvant (modified Mycobacterium butyricum) in rats. The antiarthritic effect of CETH was studied on the 28th day of the experiment after 2 weeks of oral administration of CETH at doses of 60 and 120 mg/kg body weight. Arthritis was evaluated on the last day of the experiment on the injected animal paw using X‐ray computerized microtomography and histopathology analysis methods. The CETH effect was compared with the non‐steroidal anti‐inflammatory drug diclofenac sodium (5 mg/kg). Oral administration of CETH was accompanied by effective dose‐dependent correction of morphological changes caused by the adjuvant injection. CETH had relatively high recovery effects in terms of parameters for reducing inflammation, inhibition of osteolysis, reduction in the inflammatory reaction of periarticular tissues, and cartilage degeneration. This study presents for the first time that CETH may be a powerful potential nutraceutical agent or bioactive component in the treatment of rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

Exposure to heat stress triggers a well‐defined acute response marked by HSF1‐dependent transcriptional upregulation of heat shock proteins. Cells allowed to recover acquire thermotolerance, but this adaptation is poorly understood. By quantitative proteomics, we discovered selective upregulation of HSP70‐family chaperone HSPA1 and its co‐factors, HSPH1 and DNAJB1, in MCF7 breast cancer cells acquiring thermotolerance. HSPA1 was found to have dual function during heat stress response: (i) During acute stress, it promotes the recruitment of the 26S proteasome to translating ribosomes, thus poising cells for rapid protein degradation and resumption of protein synthesis upon recovery; (ii) during thermotolerance, HSPA1 together with HSPH1 maintains ubiquitylated nascent/newly synthesized proteins in a soluble state required for their efficient proteasomal clearance. Consistently, deletion of HSPH1 impedes thermotolerance and esophageal tumor growth in mice, thus providing a potential explanation for the poor prognosis of digestive tract cancers with high HSPH1 and nominating HSPH1 as a cancer drug target. We propose dual roles of HSPA1 either alone or in complex with HSPH1 and DNAJB1 in promoting quality control of nascent/newly synthesized proteins and cellular thermotolerance. Synopsis: How cells exposed to heat stress acquire thermotolerance is poorly understood. Here, quantitative proteomics identifies upregulation of HSP70‐family chaperone HSPA1, which fulfills dual function in quality control of nascent proteins at translating ribosomes. Proteotoxic stress causes translation arrest, ubiquitylation of nascent/newly synthesized proteins, and proteasome recruitment to ribosomes.Proteasome recruitment to ribosomes is augmented by HSP70 activity independently of nascent chain ubiquitylation.HSPA1 in complex with HSPH1‐DNAJB1 cofactors maintains solubility and proteasomal clearance of ubiquitylated proteins.Low HSPH1 expression impedes nascent‐protein quality control and tumor growth, correlating with favorable outcome. [ABSTRACT FROM AUTHOR]

Objective: To assess the audiological and long-term medical and technical follow-up outcomes of an active middle ear implant.Methods: This was a retrospective medical chart analysis of all patients provided with an active middle ear implant in a tertiary academic medical referral center between September 1, 1998, and July 31, 2015. Main outcome measures were medical and technical complications, revisions, reimplantations, explantations, coupling approaches, mean time of use, pre- and postoperative hearing thresholds, functional hearing gain across frequencies (250-4,000 Hz), and Freiburg monosyllablic word test at 65 dB.Results: One hundred and three patients were identified. Fifteen were implanted bilaterally (n = 118 Vibrant Soundbridge devices [MED-EL, Innsbruck, Austria]). Seventy-seven devices were implanted for sensorineural and 41 for mixed and conductive hearing loss. Patients used the implant for 6.7 years (range 0.7 months-17.9 years) on average. Ninety-one patients (77.12%) were using the device at the end of the observation period. An overall complication rate of 16.1% was observed. The revision and explantation rates were higher for devices implanted between 2004 and 2006. The device failure rate was 3.4%. Audiological evaluation showed significant hearing gains for both hearing loss patient groups.Conclusion: This long-term follow-up reveals the reliability of the active middle ear implant in a single center. Overall complication rate and device failure rate are acceptable. The complication rate was higher during implementation of alternative coupling approaches. The audiological benefit was satisfactory in patients with all hearing loss types. The majority of implanted patients used the implant at the end of the observation period.Level Of Evidence: 4 Laryngoscope, 129:477-481, 2019. [ABSTRACT FROM AUTHOR]

The present review reports on the preparation and atomic‐scale characterization of the thinnest possible films of the glass‐forming materials silica and germania. To this end state‐of‐the‐art surface science techniques, in particular scanning probe microscopy, and density functional theory calculations have been employed. The investigated films range from monolayer to bilayer coverage where both, the crystalline and the amorphous films, contain characteristic XO4 (X=Si,Ge) building blocks. A side‐by‐side comparison of silica and germania monolayer, zigzag phase and bilayer films supported on Mo(112), Ru(0001), Pt(111), and Au(111) leads to a more general comprehension of the network structure of glass former materials. This allows us to understand the crucial role of the metal support for the pathway from crystalline to amorphous ultrathin film growth. [ABSTRACT FROM AUTHOR]

A series of unusual sialic acid analogs were prepared using a semi‐synthetic strategy. Truncation of natural N‐acetylneuraminic acid was followed by diastereoselective carbon backbone reconstruction using Barbier‐type carboligations as well as different functional group interconversions, which provided access to a variety of functional motifs in the terminal carbon backbone, including examples of saturated and unsaturated, linear and branched alkyl chains, partially deoxygenated sialic acids, sialic diacids and a first truncated legionaminic acid analog. The synthetic sialic acid probes were studied for nucleotide activation by the CMP‐sialic acid synthetase from Neisseria meningitidis using a universal pH‐shift assay for kinetic analysis. One‐pot enzymatic nucleotide activation and sialyltransfer to lactose was performed using a selection of five probes together with an engineered α2,3‐sialyltransferase from Photobacterium phosphoreum to furnish five new‐to‐nature analogs of the GM3 trisaccharide, which were finally utilized to test the substrate tolerance of two bacterial sialidases. The obtained set of sialic acid analogs and neo‐sialocojugates provides interesting opportunities for further glycobiology studies. [ABSTRACT FROM AUTHOR]

The thermostable transketolase from Geobacillus stearothermophilus (TKgst) was successfully engineered for the synthesis of aliphatic acyloins with varying carbon backbone lengths (C5−C10) based on protein structure‐guided studies. Efficient TKgst variants were identified with enhanced activities for substrate combinations of aliphatic aldehydes as acceptors together with aliphatic pyruvate homologues as donors. The TKgst single variant L382F was able to catalyze efficiently the transfer of the ketol group from hydroxypyruvate on all targeted aliphatic aldehydes (C3−C8) to give the corresponding 1,3‐dihydroxy ketones with good yields and excellent enantioselectivity. The combination of the H102L/H474S mutation previously designed for the improved utilization of aliphatic pyruvate homologues together with a F435I exchange gave the new variant H102L/H474S/F435I, which is able to transfer the acyl goup of 2‐oxobutyrate and 2‐oxovalerate to aliphatic aldehydes, giving mono hydroxylated ketones. [ABSTRACT FROM AUTHOR]

Defined sialoglycoconjugates are important molecular probes for studying the role of sialylated glycans in biological systems. We show that the α2,3‐sialyltransferase from Photobacterium phosphoreum JT‐ISH‐467 (2,3SiaTpph) tolerates a very broad substrate scope for modifications in the sialic acid part, including bulky amide variation, C5/C9 substitution, and C5 stereoinversion. To reduce the enzyme's hydrolytic activity, which erodes the product yield, an extensive structure‐guided mutagenesis study identified three variants that show up to five times higher catalytic efficiency for sialyltransfer, up to ten times lower efficiency for substrate hydrolysis, and drastically reduced product hydrolysis. Variant 2,3SiaTpph (A151D) displayed the best performance overall in the synthesis of the GM3 trisaccharide (α2,3‐Neu5Ac‐Lac) from lactose in a one‐pot, two‐enzyme cascade. Our study demonstrates that several complementary solutions can be found to suppress the common problem of undesired hydrolysis activity of microbial GT80 sialyltransferases. The new enzymes are powerful catalysts for the synthesis of a wide variety of complex natural and new‐to‐nature sialoconjugates for biological studies. [ABSTRACT FROM AUTHOR]

Within the thermal energy storage initiative, National Demonstrator for IseNtropic Energy (NADINE) storage, three projects are carried out focusing on thermal energy storage at different temperature levels. Thermal storage units are key components of Carnot batteries, which are based on the intermediate conversion of electric energy into heat. Pumped thermal energy storage (PTES) is an emerging Carnot battery concept variant for the flexible management of supply and demand of electricity, heat, and cold. A counterclockwise thermodynamic cycle operated by surplus electricity is used to charge a thermal storage, which delivers heat to operate a power cycle during discharge. The absence of geographic constraints, a theoretical roundtrip efficiency of 100%, and a small environmental footprint are promising features of PTES. PTES is also able to provide low‐cost backup capacity in case of shortages in available renewable energy. Various options are proposed for the technical implementation of PTES, using various combinations of engines, thermal storage units, and working fluids. The resulting systems differ in efficiency, costs, maturity, and complexity. Herein, a thermodynamic analysis of five different PTES variants is presented. The results should help to identify priorities in the further development of the PTES variants. [ABSTRACT FROM AUTHOR]

A protein engineering approach for expanding the substrate scope of the (S)‐selective Chromobacterium violaceum amine transaminase is presented. Amino acid residues in the small binding pocket of the active site were targeted in order to increase the pocket size for acceptance of primary amines bearing two bulky groups. A highly sensitive fluorescence assay was then used to evaluate the generated enzyme variants for their activity towards propyl‐ and benzyl‐substituted screening substrates. The best variant, L59A/F88A, was successfully applied in the kinetic resolution of 1,2‐diphenylethylamine using different conditions and substrate loadings. The variant L59A/F88A generated enantiomerically pure (R)‐1,2‐diphenylethylamine with ee>99% under all tested conditions. The variant also holds great promise for synthesis of hydrophobic compounds as it shows optimum activity when 20‐30% (v/v) DMSO is applied as cosolvent. The variant L59A/F88A provides a great addition to the available catalyst toolbox for synthesis of chiral amines, as it is the first published (S)‐selective amine transaminase showing activity towards benzyl‐substituted primary amines. [ABSTRACT FROM AUTHOR]

We describe an efficient three‐enzyme, sequential one‐pot cascade reaction where both transketolase substrates are generated in situ in a convergent fashion. The nucleophilic donor substrate hydroxypyruvate was obtained from l‐serine and pyruvate by a transaminase‐catalyzed reaction. In parallel, three different (2S)‐α‐hydroxylated aldehydes, l‐glyceraldehyde, d‐threose, and l‐erythrose, were generated as electrophilic acceptors from simple achiral compounds glycolaldehyde and formaldehyde by d‐fructose‐6‐phosphate aldolase catalysis. The compatibility of the three enzymes was studied in terms of temperature, enzyme ratio and substrate concentration. The efficiency of the process relied on the irreversibility of the transketolase reaction, driving a shift of the reversible transamination reaction and securing the complete conversion of all substrates. Three valuable (3S,4S)‐ketoses, l‐ribulose, d‐tagatose, and l‐psicose were obtained in good yields with high diastereoselectivity. [ABSTRACT FROM AUTHOR]

NAD(P)H:quinone oxidoreductase 1 (NQO1) is a human FAD‐dependent enzyme that plays a crucial role in the antioxidant defense system. A naturally occurring single‐nucleotide polymorphism (NQO1*2) in the NQO1 gene leads to an amino acid substitution (P187S), which severely compromises the activity and stability of the enzyme. The NQO1*2 genotype has been linked to a higher risk for several types of cancer and poor survival rate after anthracycline‐based chemotherapy. In this study, we show that a small molecular chaperone (N‐(2‐bromophenyl)pyrrolidine‐1‐sulfonamide) repopulates the native wild‐type conformation. As a consequence of the stabilizing effect, the enzymatic activity of the P187S variant protein is strongly improved in the presence of the molecular chaperone in vitro. [ABSTRACT FROM AUTHOR]

Background and Purpose: In acute stroke, arterial-input-function (AIF) determination is essential for obtaining perfusion estimates with dynamic susceptibility-weighted contrast-enhanced magnetic resonance imaging (DSC-MRI). Standard DSC-MRI postprocessing applies single AIF selection, ie, global AIF. Physiological considerations, however, suggest that a multiple AIFs selection method would improve perfusion estimates to detect penumbral flow. In this study, we developed a framework based on comparable DSC-MRI and positron emission tomography (PET) images to compare the two AIF selection approaches and assess their performance in penumbral flow detection in acute stroke.Methods: In a retrospective analysis of 17 sub(acute) stroke patients with consecutive MRI and PET scans, voxel-wise optimized AIFs were calculated based on the kinetic model as derived from both imaging modalities. Perfusion maps were calculated based on the optimized-AIF using two methodologies: (1) Global AIF and (2) multiple AIFs as identified by cluster analysis. Performance of penumbral-flow detection was tested by receiver-operating characteristics (ROC) curve analysis, ie, the area under the curve (AUC).Results: Large variation of optimized AIFs across brain voxels demonstrated that there is no optimal single AIF. Subsequently, the multiple-AIF method (AUC range over all maps: .82-.90) outperformed the global AIF methodology (AUC .72-.85) significantly.Conclusions: We provide PET imaging-based evidence that a multiple AIF methodology is beneficial for penumbral flow detection in comparison with the standard global AIF methodology in acute stroke. [ABSTRACT FROM AUTHOR]

A new two‐dimensional (2D) germanium dioxide film has been prepared. The film consists of interconnected germania tetrahedral units forming a bilayer structure, weakly coupled to the supporting Pt(111) metal‐substrate. Density functional theory calculations predict a stable structure of 558‐membered rings for germania films, while for silica films 6‐membered rings are preferred. By varying the preparation conditions the degree of order in the germania films is tuned. Crystalline, intermediate ordered and purely amorphous film structures are resolved by analysing scanning tunnelling microscopy images. [ABSTRACT FROM AUTHOR]

No Abstract [ABSTRACT FROM AUTHOR]

We described an efficient in situ generation of hydroxypyruvate from d‐serine catalyzed by a d‐amino acid oxidase from Rhodotorula gracilis. This strategy revealed an interesting alternative to the conventional chemical synthesis of hydroxypyruvate starting from toxic bromopyruvate or to the enzymatic transamination from l‐serine requiring an additional substrate as amino acceptor. Hydroxypyruvate thus produced was used as donor substrate of transketolases from Escherichia coli or from Geobacillus stearothermophilus catalyzing the stereoselective formation of a carbon−carbon bond. The enzymatic cascade reaction was performed in one‐pot in the presence of d‐serine and appropriate aldehydes for the synthesis of valuable (3S)‐hydroxyketones, which were obtained with high enantio‐ and diastereoselectivity and in good yield. The efficiency of the process was based on the irreversibility of both reactions allowing complete conversion of d‐serine and aldehydes. [ABSTRACT FROM AUTHOR]

Nitrogen heterocycles are structural motifs found in many bioactive natural products and of utmost importance in pharmaceutical drug development. In this work, a stereoselective synthesis of functionalized N‐heterocycles was accomplished in two steps, comprising the biocatalytic aldol addition of ethanal and simple aliphatic ketones such as propanone, butanone, 3‐pentanone, cyclobutanone, and cyclopentanone to N‐Cbz‐protected aminoaldehydes using engineered variants of d‐fructose‐6‐phosphate aldolase from Escherichia coli (FSA) or 2‐deoxy‐d‐ribose‐5‐phosphate aldolase from Thermotoga maritima (DERATma) as catalysts. FSA catalyzed most of the additions of ketones while DERATma was restricted to ethanal and propanone. Subsequent treatment with hydrogen in the presence of palladium over charcoal, yielded low‐level oxygenated N‐heterocyclic derivatives of piperidine, pyrrolidine and N‐bicyclic structures bearing fused cyclobutane and cyclopentane rings, with stereoselectivities of 96–98 ee and 97:3 dr in isolated yields ranging from 35 to 79%. [ABSTRACT FROM AUTHOR]

Objective: Accurate identification of the ischemic penumbra, the therapeutic target in acute clinical stroke, is of critical importance to identify patients who might benefit from reperfusion therapies beyond the established time windows. Therefore, we aimed to validate magnetic resonance imaging (MRI) mismatch–based penumbra detection against full quantitative positron emission tomography (15O‐PET), the gold standard for penumbra detection in acute ischemic stroke. Methods: Ten patients (group A) with acute and subacute ischemic stroke underwent perfusion‐weighted (PW)/diffusion‐weighted MRI and consecutive full quantitative 15O‐PET within 48 hours of stroke onset. Penumbra as defined by 15O‐PET cerebral blood flow (CBF), oxygen extraction fraction, and oxygen metabolism was used to validate a wide range of established PW measures (eg, time‐to‐maximum [Tmax]) to optimize penumbral tissue detection. Validation was carried out using a voxel‐based receiver‐operating‐characteristic curve analysis. The same validation based on penumbra as defined by quantitative 15O‐PET CBF was performed for comparative reasons in 23 patients measured within 48 hours of stroke onset (group B). Results: The PW map Tmax (area‐under‐the‐curve = 0.88) performed best in detecting penumbral tissue up to 48 hours after stroke onset. The optimal threshold to discriminate penumbra from oligemia was Tmax >5.6 seconds with a sensitivity and specificity of >80%. Interpretation: The performance of the best PW measure Tmax to detect the upper penumbral flow threshold in ischemic stroke is excellent. Tmax >5.6 seconds–based penumbra detection is reliable to guide treatment decisions up to 48 hours after stroke onset and might help to expand reperfusion treatment beyond the current time windows. ANN NEUROL 2019;85:875–886. [ABSTRACT FROM AUTHOR]

BACKGROUND Producing statin side‐chains by sequential aldol condensation catalyzed by 2‐deoxyribose‐5‐phosphate aldolase (DERA) (EC 4.1.2.4) is the best‐known and most promising synthetic route. The advantage of this process is the formation of two stereocenters in a single step starting from inexpensive achiral components, acetaldehyde and chloroacetaldehyde. The limitation for the industrial‐scale application is enzyme inactivation caused by substrates as well by the intermediate produced by single aldol addition. RESULTS: The DERA enzyme from Thermotoga maritima (DERATm) was investigated extensively in this work. The influence of aldehydes on DERATm stability was studied in detail. Mathematical models in different reactor configurations were developed based on experimentally determined kinetic parameters of all reactions included in the synthesis of statin side‐chain. Models also included enzyme inactivation by all compounds with negative impact on its stability. Mathematical model‐based optimization enabled optimization of process conditions and reactor configuration. The fed‐batch reactor proved to be the most suitable choice achieving product concentration of 78 g L−1, productivity of 56 g L day−1 and yield of 95% under an optimal condition. CONCLUSION: The validated mathematical model and applied methodology can be exploited for further process improvement and for process design of similar systems. © 2019 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Enzymes are attractive tools for synthetic applications. To be viable for industrial use, enzymes need sufficient stability towards the desired reaction conditions such as high substrate and cosolvent concentration, non‐neutral pH and elevated temperatures. Thermal stability is an attractive feature not only because it allows for protein purification by thermal treatment and higher process temperatures but also due to the associated higher stability against other destabilising factors. Therefore, high‐throughput screening (HTS) methods are desirable for the identification of thermostable biocatalysts by discovery from nature or by protein engineering but current methods have low throughput and require time‐demanding purification of protein samples. We found that nanoscale differential scanning fluorimetry (nanoDSF) is a valuable tool to rapidly and reliably determine melting points of native proteins. To avoid intrinsic problems posed by crude protein extracts, hypotonic extraction of overexpressed protein from bacterial host cells resulted in higher sample quality and accurate manual determination of several hundred melting temperatures per day. We have probed the use of nanoDSF for HTS of a phylogenetically diverse aldolase library to identify novel thermostable enzymes from metagenomic sources and for the rapid measurements of variants from saturation mutagenesis. The feasibility of nanoDSF for the screening of synthetic reaction conditions was proved by studies of cosolvent tolerance, which showed protein melting temperature to decrease linearly with increasing cosolvent concentration for all combinations of six enzymes and eight water‐miscible cosolvents investigated, and of substrate affinity, which showed stabilisation of hexokinase by sugars in the absence of ATP cofactor. Enzymes: Alcohol dehydrogenase (NADP+) (EC 1.1.1.2), transketolase (EC 2.2.1.1), hexokinase (EC 2.7.1.1), 2‐deoxyribose‐5‐phosphate aldolase (EC 4.1.2.4), fructose‐6‐phosphate aldolase (EC 4.1.2.n). nanoDSF is a valuable tool to rapidly determine thermal stability of native proteins in crude protein extracts. It can be used for high‐throughput screening of enzyme libraries from metagenomic sources or from saturation mutagenesis, for rapid screening of tolerance for water‐miscible organic cosolvent and of substrate affinity, for example, sugar binding by hexokinase even in the absence of ATP. [ABSTRACT FROM AUTHOR]

The article discusses a direct comparison of mastoidal and retrosigmoidal placement of a transcutaneous bone conduction device after canal wall down tympanoplasty. Topics include how after extensive cholesteatoma surgery, a transcutaneous bone conduction implant is a valuable hearing rehabilitation tool in patients where conventional middle ear reconstruction is ineffective and how both retrosigmoidal and mastoidal implantation achieve good postoperative hearing results.

Glucose consumption via glycolysis and its biosynthesis via gluconeogenesis are central reciprocal pathways controlled by a set of different enzymes. In the yeast Saccharomyces cerevisiae, expression of gluconeogenic enzymes is induced when cells are devoid of glucose. Availability of glucose immediately leads to inactivation and rapid degradation of these enzymes via the ubiquitin proteasome system. Polyubiquitination is carried out by the Gid complex, a multisubunit RING E3 ligase that constitutively consists of six different proteins. Upon addition of glucose to the medium, the substrate recognition subunit Gid4 appears within minutes and triggers ubiquitination of the gluconeogenic enzymes. Here, we show that Gid4 is tightly regulated on the transcriptional and protein level to ensure proper adjustment of gluconeogenesis. [ABSTRACT FROM AUTHOR]

Summary: This study reports the prognostic impact of the expression of the natural killer cell marker CD56 in a large series of risk‐adapted paediatric patients with T cell acute lymphoblastic leukaemia (T‐ALL; n = 493) treated within the ALL‐Berlin‐Frankfurt‐Münster (BFM) 2000 protocol. The immunophenotype was analysed centrally at diagnosis using flow cytometry and correlated with clinical parameters and outcome. CD56 expression was detected in 7·1% and early T‐cell precursor (ETP) phenotype in 6·7% of all T‐ALL patients. The percentage of ETP in the CD56+ T‐ALL cohort was 4‐fold higher than in the whole cohort. CD56+ T‐ALL frequently expressed the progenitor marker CD34 and myeloid antigens CD13 and CD33. The 5‐year event‐free survival (EFS) rates for the European Group for the Immunological classification of Leukaemias/World Health Organization subgroups and the ETP phenotype were not statistically different. By contrast, patients with CD56 expression had a significantly reduced EFS (60 ± 8%) and overall survival (60 ± 8%) at 5 years, with a hazard ratio of 2·46 (P = 0·002) and 2·99 (P < 0·001), respectively. Moreover, CD56 expression in combination with the minimal residual disease (MRD)‐based high risk assignment defined a population with a 'very‐high' risk probability of relapse in the ALL‐BFM 2000 trial. The CD56 marker has the potential to augment MRD‐based risk stratification and may serve as a molecular target for antibody‐based treatment strategies in childhood T‐ALL. [ABSTRACT FROM AUTHOR]

Abstract: A structure‐guided engineering of fructose‐6‐phosphate aldolase was performed to expand its substrate promiscuity toward aliphatic nucleophiles, that is, unsubstituted alkanones and alkanals. A “smart” combinatorial library was created targeting residues D6, T26, and N28, which form a binding pocket around the nucleophilic carbon atom. Double‐selectivity screening was executed by high‐performance TLC that allowed simultaneous determination of total activity as well as a preference for acetone versus propanal as competing nucleophiles. D6 turned out to be the key residue that enabled activity with non‐hydroxylated nucleophiles. Altogether 25 single‐ and double‐site variants (D6X and D6X/T26X) were discovered that show useful synthetic activity and a varying preference for ketone or aldehyde as the aldol nucleophiles. Remarkably, all of the novel variants had completely lost their native activity for cleavage of fructose 6‐phosphate. [ABSTRACT FROM AUTHOR]

Precise regulation of cellular processes is essential for life. Regarding proteins, many regulatory mechanisms were explored over the years, such as posttranslational modifications (e.g., phosphorylation), enzyme activation or inhibition by small molecules, and modulation of protein–protein interactions. Complete removal of a protein via proteolysis as a regulatory mechanism, however, was denied for a long time, mainly due to economical considerations. Scientists could not believe that a protein which is synthesized at the expense of a lot of energy could be destroyed again. Here, we discuss the landmark discoveries and the use of yeast as a eukaryotic model organism that finally paved the way for our current understanding of proteolysis as an essential regulatory principle in the cell. [ABSTRACT FROM AUTHOR]

Primary leptomeningeal melanocytic tumors (PLMTs) are rare. They usually arise along the spinal cord and at the skull base. Here we report on a patient with a very rare intraventricular melanocytoma. Histologically, a melanocytic tumor was clearly diagnosed. However, to make the uncommon diagnosis of an intraventricular melanocytoma, metastatic melanoma needed to be excluded. Next generation sequencing covering gene mutations that may occur in PLMTs and cutaneous melanoma was performed. The unique gene mutation profile detected, consisting of an activating CYSLTR2 L129Q mutation and EIF1AX G9R mutation and a lack of mutations in genes known to occur in metastatic melanoma (i.e. BRAF or NRAS) confirmed the diagnosis of an intraventricular melanocytoma. This case report is the second intraventricular melanocytoma published to date and demonstrates the value of applying novel genetic assays to make this diagnosis. [ABSTRACT FROM AUTHOR]

Abstract: Transglutaminase from Streptomyces mobaraensis (MTG) has become a powerful tool to covalently and highly specifically link functional amines to glutamine donor sites of therapeutic proteins. However, details regarding the mechanism of substrate recognition and interaction of the enzyme with proteinaceous substrates still remain mostly elusive. We have determined the crystal structure of the Streptomyces papain inhibitory protein (SPIp), a substrate of MTG, to study the influence of various substrate amino acids on positioning glutamine to the active site of MTG. SPIp exhibits a rigid, thermo‐resistant double‐psi‐beta‐barrel fold that is stabilized by two cysteine bridges. Incorporation of biotin cadaverine identified Gln‐6 as the only amine acceptor site on SPIp accessible for MTG. Substitution of Lys‐7 demonstrated that small and hydrophobic residues in close proximity to Gln‐6 favor MTG‐mediated modification and are likely to facilitate introduction of the substrate into the front vestibule of MTG. Moreover, exchange of various surface residues of SPIp for arginine and glutamate/aspartate outside the glutamine donor region influences the efficiency of modification by MTG. These results suggest the occurrence of charged contact areas between MTG and the acyl donor substrates beyond the front vestibule, and pave the way for protein engineering approaches to improve the properties of artificial MTG‐substrates used in biomedical applications. [ABSTRACT FROM AUTHOR]

Abstract: In chemistry and physics the electronic charge on a species or material is one important determinant of its properties. In the present Minireview, the essential requirements for a model catalyst system suitable to study charge control are discussed. The ideal model catalyst for this purpose consists of a material system, which comprises a single crystal metal support, covered by an epitaxially grown ultrathin oxide film, and flat, two‐dimensional nanoparticles residing on this film. Several examples from the literature are selected and presented, which illustrate various aspects of electron transport from the support to the nanoparticle and vice versa. Key experiments demonstrate charge control within such model catalysts and give direct evidence for a chemical reaction at the perimeter of Au nanoparticles. The concepts derived from these studies are then taken a step further to see how they may be applied for bulk powder oxide supported nanoparticles as they are frequently found in catalytically active materials. [ABSTRACT FROM AUTHOR]

Measuring product properties during vinylacetate-ethylene (VAE) polymerizations can be difficult due to economic and technical limitations. The use of soft sensors, mathematical methods using available process data (current and historic), can be an effective solution to infer the sought after property and calculate properties not directly measurable. The setup of a soft sensor in an industrial environment for a long term, successful application needs to take into account several additional hurdles. These include the variability of the process, soft factors leading to the acceptance of this tool in production, and the effort needed for long-term support and maintenance among others. These points are illuminated using the successful development and implementation of a VAE dispersion process based tile adhesive tensile strength soft sensor. [ABSTRACT FROM AUTHOR]

Copyright of Bautechnik is the property of Wiley-Blackwell 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.)

To demonstrate the accuracy of fully automated, quantitative, volumetric measurement of the amount of fibroglandular breast tissue (FGT), using MRI, and to investigate the impact of different MRI sequences using anthropomorphic breast phantoms as the ground truth. In this study, 10 anthropomorphic breast phantoms that consisted of different known fractions of adipose and protein tissue, which closely resembled normal breast parenchyma, were developed. Anthropomorphic breast phantoms were imaged with a 1.5 T unit (Siemens, Avantofit) using an 18-channel breast coil. The sequence protocol consisted of an isotropic Dixon sequence (Di), an anisotropic Dixon sequence (Da), and T1 3D FLASH sequences with and without fat saturation (T1). Fully automated, quantitative, volumetric measurement of FGT for all anthropomorphic phantoms and sequences was performed and correlated with the amounts of fatty and protein components in the phantoms as the ground truth. Fully automated, quantitative, volumetric measurements of FGT with MRI for all sequences ranged from 5.86 to 61.05% (mean 33.36%). The isotropic Dixon sequence yielded the highest accuracy (median 0.51%-0.78%) and precision (median range 0.19%) compared with anisotropic Dixon (median 1.92%-2.09%; median range 0.55%) and T1-weighted sequences (median 2.54%-2.46%; median range 0.82%). All sequences yielded good correlation with the FGT content of the anthropomorphic phantoms. The best correlation of FGT measurements was identified for Dixon sequences (Di, R2 = 0.999; Da, R2 = 0.998) compared with conventional T1-weighted sequences ( R2 = 0.971). MRI yields accurate, fully automated, quantitative, volumetric measurements of FGT, an increasingly important and sensitive imaging biomarker for breast cancer risk. Compared with conventional T1 sequences, Dixon-type sequences show the highest correlation and reproducibility for automated, quantitative, volumetric FGT measurements using anthropomorphic breast phantoms as the ground truth. [ABSTRACT FROM AUTHOR]

Enzymes catalyzing asymmetric carboligation reactions typically show very high substrate specificity for their nucleophilic donor substrate components. Structure-guided engineering of the thermostable transketolase from Geobacillus stearothermophilus by directed in vitro evolution yielded new enzyme variants that are able to utilize pyruvate and higher aliphatic homologues as nucleophilic components for acyl transfer instead of the natural polyhydroxylated ketose phosphates or hydroxypyruvate. The single mutant H102T proved the best hit toward 3-methyl-2-oxobutyrate as donor, while the double variant H102L/H474S showed highest catalytic efficiency toward pyruvate as donor. The latter variant was able to complement the auxotrophic deficiency of Escherichia coli cells arising from a deletion of the dxs gene, which encodes for activity of the first committed step into the terpenoid biosynthesis, offering the chance to employ a growth selection test for further enzyme optimization. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell 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.)

The human NAD(P)H:quinone oxidoreductase 1 ( NQO1; ) is an essential enzyme in the antioxidant defence system. Furthermore, NQO1 protects tumour suppressors like p53, p33 ING1b and p73 from proteasomal degradation. The activity of NQO1 is also exploited in chemotherapy for the activation of quinone-based treatments. Various single nucleotide polymorphisms are known, such as NQO1*2 and NQO1*3 yielding protein variants of NQO1 with single amino acid replacements, i.e. P187S and R139W, respectively. While the former NOQ1 variant is linked to a higher risk for specific kinds of cancer, the role, if any, of the arginine 139 to tryptophan exchange in disease development remains obscure. On the other hand, mitomycin C-resistant human colon cancer cells were shown to harbour the NQO1*3 variant resulting in substantially reduced enzymatic activity. However, the molecular cause for this decrease remains unclear. In order to resolve this issue, recombinant NQO1 R139W has been characterized biochemically and structurally. In this report, we show by X-ray crystallography and 2D- NMR spectroscopy that this variant adopts the same structure both in the crystal as well as in solution. Furthermore, the kinetic parameters obtained for the variant are similar to those reported for the wild-type protein. Similarly, thermostability of the variant was only slightly affected by the amino acid replacement. Therefore, we conclude that the previously reported effects in human cancer cells cannot be attributed to protein stability or enzyme activity. Instead, it appears that loss of exon 4 during maturation of a large fraction of pre- mRNA is the major reason of the observed lack of enzyme activity and hence reduced activation of quinone-based chemotherapeutics. [ABSTRACT FROM AUTHOR]

d-Fructose-6-phosphate aldolase (FSA) was probed for extended nucleophile promiscuity by using a series of fluorogenic substrates to reveal retro-aldol activity. Four nucleophiles ethanal, propanone, butanone, and cyclopentanone were subsequently confirmed to be non-natural substrates in the synthesis direction using the wild-type enzyme and its D6H variant. This exceptional widening of the nucleophile substrate scope offers a rapid entry, in good yields and high stereoselectivity, to less oxygenated alkyl ketones and aldehydes, which was hitherto impossible. [ABSTRACT FROM AUTHOR]

Ubiquitylation controls protein function and degradation. Therefore, ubiquitin ligases need to be tightly controlled. We discovered an evolutionarily conserved allosteric restraint mechanism for Nedd4 ligases and demonstrated its function with diverse substrates: the yeast soluble proteins Rpn10 and Rvs167, and the human receptor tyrosine kinase FGFR1 and cardiac IKS potassium channel. We found that a potential trimerization interface is structurally blocked by the HECT domain α1-helix, which further undergoes ubiquitylation on a conserved lysine residue. Genetic, bioinformatics, biochemical and biophysical data show that attraction between this α1-conjugated ubiquitin and the HECT ubiquitin-binding patch pulls the α1-helix out of the interface, thereby promoting trimerization. Strikingly, trimerization renders the ligase inactive. Arginine substitution of the ubiquitylated lysine impairs this inactivation mechanism and results in unrestrained FGFR1 ubiquitylation in cells. Similarly, electrophysiological data and TIRF microscopy show that NEDD4 unrestrained mutant constitutively downregulates the IKS channel, thus confirming the functional importance of E3-ligase autoinhibition. [ABSTRACT FROM AUTHOR]

A specific and sensitive electrochemical biosensor with human monoamine oxidase B (hMAO B) as biological receptor and a MnO2 modified nanomaterial based transducer system has been developed and optimised. Best results for the biosensor were achieved when using enzyme immobilisation with a dialysis membrane (regenerated cellulose, molecular weight cut-off 14000) and a 20 % (m/m) MnO2 modified multi-walled carbon nanotubes (MWCNTs, ratio of fluid to solid compounds of 1 : 0.7 (m/m)) paste electrode smoothed with a glassy carbon paste (GCP, ratio 1 : 3.6 (m/m)) containing the same mediator concentration. The biosensor was operated in a flow injection analysis (FIA) system with Sørensen phosphate buffer (33 mM, pH 7.5) and amperometric detection at a fixed potential of +400 mV vs. Ag/AgCl. The developed sensor underwent validation using phenylethylamine (PEA) as standard substrate showing linearity between 5.0 and 400 µM PEA and limits of detection and quantification of 1.5 and 5.0 µM PEA, respectively. The sensor was successfully tested for the determination of total monoamines in rat brain calculated as PEA equivalents showing a result of 1.2 µg/g brain tissue (n=3, relative standard deviation 4.4 %). [ABSTRACT FROM AUTHOR]

The sequence of a glycan and its topology of presentation team up to determine the specificity and selectivity of recognition by saccharide receptors (lectins). Structure-activity analysis would be furthered if the glycan part of a glycocluster could be efficiently elaborated in situ while keeping all other parameters constant. By using a bacterial α2,6-sialyltransferase and a small library of bi- to tetravalent glycoclusters, we illustrate the complete conversion of scaffold-presented lactoside units into two different sialylated ligands based on N-acetyl/glycolyl-neuraminic acid incorporation. We assess the ensuing effect on their bioactivity for a plant toxin, and present an analysis of the noncovalent substrate binding contacts that the added sialic acid moiety makes to the lectin. Enzymatic diversification of a scaffold-presented glycan can thus be brought to completion in situ, offering a versatile perspective for rational glycocluster engineering. [ABSTRACT FROM AUTHOR]