Biology subjects

Hurevich, M.

Publications and source records attributed to Hurevich, M..

4 recordsLinked to original sources

bioRxiv2026

Rapid Electrochemical Biosensing of Listeria monocytogenes Using Rationally Designed Host-Pathogen Interface Peptides

Rapid, selective detection of bacterial pathogens remains a central challenge. Here we report a label-free electrochemical biosensing approach that leverages protein-protein interaction (PPI)-derived peptides as recognition elements for rapid detection of Listeria monocytogenes (LM). The sensor design is inspired by the interaction between the LM virulence factor Internalin A (InlA) and the human host receptor E-cadherin (E-Cad1). Peptides derived from the InlA-binding domain of E-Cad1 were engineered as molecular recognition elements, with the E-Cad1(15-24) peptide displaying micromolar affinity and selective binding towards LM. Immobilization of these peptides on gold electrodes enabled bacterial detection by electrochemical impedance spectroscopy within 10 minutes, without labels or external signal amplification. A low peptide surface density was associated with enhanced binding-site accessibility and may facilitate multivalent interactions between the bacterial surface and the immobilized peptides. The platform produced a detectable response at experimentally tested concentrations as low as 1 CFU mL {superscript 1} and exhibited excellent selectivity under the conditions examined. This work introduces a chemically programmable, PPI-inspired biosensing paradigm that uses a reductionist approach and could potentially be extended to other pathogen targets.

bioengineering↗

bioRxiv2026

Site-specific phosphorylation of Ser352 drives aggregation of Tau R4 under acidosis conditions

In Alzheimers disease, neurons undergo acidosis as their pH drops from [~]7.1 to [~]6.5. Here we elucidate the molecular mechanism of specific Tau aggregation only at this lower pH. We show that a specific phosphorylation event in the Tau R4 domain is coupled to this pH drop to drive a defined phase transition from condensates to fibrils. Using a combination of experimental and computational studies, our results demonstrate that site-specific phosphorylation of Ser352 is the molecular switch that induces aggregation of Tau only at the more acidic, disease-related pH. We designed and synthesized a phosphopeptide library covering all phosphorylation patterns of the Tau-R4 domain and tested its response to controlled acidification using an array of complementary biophysical methods. This revealed that only a single phosphorylation of Ser352 led to acid-driven aggregation of Tau-R4. At neutral pH, Tau-R4 with a phosphorylation on Ser352 formed liquid condensates. These condensates converted irreversibly into amyloid filaments as the pH gradually decreased towards the level associated with pathological acidosis. Using a combination of 3{superscript 1}P-and 1H - NMR, MD simulations and microscopy studies, we show that the mechanism by which the phosphorylation of Ser352 Tau R4 exerts its effects is based on the unique position of this residue within the protein structure. pSer352 is located at the inside of the tip of a {beta}-hairpin, pointing into the hydrophobic core of the amyloid fold. This buried position increases its effective pK{square}, resulting in compacting of the hairpin following pSer352 protonation upon acidification. This shortens the inter-sheet distance at this position and tightens the filament. We conclude that this single protonation event of the pSer352 phosphate is responsible for the macroscopic phase transition from condensates to aggregates. Our results provide the molecular explanation for the specific aggregation of Tau under the pathologically relevant acidic pH, which is substantially different from its behavior at neutral pH.

biochemistry↗

bioRxiv2024

The role of specific phosphorylation patterns in the oligomerization of Tau-R4

Specific phosphorylation patterns control the activity of multiphosphorylated proteins. In case of the Tau protein, multiphosphorylation leads to the formation of different disease-related condensates and aggregates. Studying the role of these specific patterns at the protein level is crucial for understanding the molecular mechanisms of Tauopathies such as Alzheimers Disease. However, due to the extreme difficulty in obtaining recombinant proteins with specific phosphorylation patterns using kinase-based methods, it is practically impossible to study the connection between specific phosphorylation patterns and aggregation events at the protein level. Here we addressed this problem by reducing the system to the peptide level and studying the effect of specific phosphorylation patterns on the condensation and aggregation of a specific domain of Tau, R4 (residues 336-358). To achieve this aim, we have applied advanced methods to synthesize a library of multiphosphorylated peptides derived from R4. We showed that specific phosphorylation patterns stringently control the formation of Tau aggregates and condensates. Phosphorylation of Ser341 promoted aggregation of R4 while phosphorylation of Ser352 promoted its condensation. Interestingly, Ser356 phosphorylation inhibited both processes, which can be overridden by double-phosphorylation at Ser341/Ser352. Differences between the microenvironments of the phosphorylated residues lead to their different effects on R4 aggregation upon phosphorylation. Our results show that working at the domain level using advanced peptide synthesis methods is a highly useful and practical way to provide valuable information about the effects of post translational modifications on protein activity.

biochemistry↗

bioRxiv2017

A combinatorial approach for the synthesis of multi-phosphorylated peptides: new tool for studying phosphorylation patterns in proteins

Phosphorylation of proteins at multiple sites creates different phosphorylation patterns that are essential for their biological activity. For example, such patterns contribute to the redirection of signalling to alternative pathways. Multi-phosphorylated peptides are excellent tools to systematically study the impact of unique phosphorylation patterns on signalling, but their synthesis is extremely difficult. Here we present an efficient and general method for the synthesis of multi-phosphorylated peptides, using a combination of different tailor-made coupling conditions. The method was demonstrated for the synthesis of a library of Rhodopsin C terminal peptides with distinct phosphorylation patterns containing up to seven phosphorylated Ser (pSer) and Thr (pThr) residues in close proximity to one another. Our method can be used to synthesize peptides incorporating multiple phosphorylated amino acids at high efficiency. It does not require any special expertise and can be performed in any standard peptide laboratory. This approach opens the way for quantitative mechanistic studies of phosphorylation patterns and their biological roles.

biochemistry↗