Biology subjects

Denard, C.

Publications and source records attributed to Denard, C..

4 recordsLinked to original sources

bioRxiv2026

Photothermal Recycling Biosensing for Continuous, Sensitive Molecular Quantification

Continuous biochemical sensing provides valuable insights into an individuals physiological state and the mechanisms underlying pathophysiological changes. However, most existing bioanalytical methods are not compatible with continuous biochemical sensing. A major technical challenge lies in achieving rapid measurement readouts while maintaining high specificity and sensitivity in complex biological fluids. Sensitive molecular detection typically requires slow analyte-binder dissociation and long incubation to reach equilibrium, whereas rapid and frequent measurements demand fast association-dissociation kinetics that are difficult to reconcile for low-abundance analytes. To address this challenge, we introduce a sensing mechanism termed photothermal recycling (PTR), which mimics the thermal cycling process in polymerase chain reaction. Using plasmonic photothermal effects, PTR rapidly recycles binders to enable frequent measurements. We demonstrate a digital PTR assay capable of multi-hour biochemical monitoring with subpicomolar(pM) sensitivity in buffer, diluted serum, and saliva. This approach leverages localized thermal energy to dynamically modulate biomolecular recognition, offering a new bioanalytical paradigm for continuous biochemical sensing across diverse application settings.

bioengineering↗

bioRxiv2025

Rational Development of Recombinant ELP Bolaamphiphiles for the Controlled Construction of Multifunctionalized Globular Protein Vesicles

Synthetic biology has enabled the development of new strategies for creating artificial cells that can sense and respond to external stimuli. This study introduces the bottom-up construction of globular protein vesicles (GPVs) that incorporate elastin-like peptide (ELP) bolaamphiphiles as transmembrane components. To enable this strategy, we devised a Golden Gate-based cloning strategy to streamline the design, expression, and purification of ELP bolaamphiphiles. Three ELP bolamphiphiles with varying structural complexity were developed, incorporating fluorescent proteins to facilitate visualization and characterization. The self-assembly of these bolaamphiphiles into GPVs was optimized by varying the molar ratios of recombinant building blocks. Structural characterization confirmed vesicle formation, dynamic light scattering analysis revealed size distributions dependent on modular complexity, and atomic force microscopy demonstrated that the vesicles exhibited MPa-range Youngs moduli, indicative of high mechanical robustness. Our findings demonstrate that multifunctional ELP bolaamphiphiles can be incorporated into GPVs, enabling modular vesicle engineering. This work provides a foundation for designing synthetic cells with customizable bi-functionalities and modularity, advancing compartmentalized systems.

synthetic biology↗

bioRxiv2025

PERRC: Protease Engineering with Reactant Residence Time Control

Proteases with engineered specificity hold great potential for targeted therapeutics, protein circuit construction, and biotechnology applications. However, many proteases exhibit broad substrate specificity, limiting their applications. Engineering protease specificity remains challenging because evolving a protease to recognize a new substrate, without counterselecting against its native substrate, often results in high residual activity on the original substrate. To address this, we developed Protease Engineering with Reactant Residence Time Control (PERRC), a platform that exploits the correlation between endoplasmic reticulum (ER) retention sequence strength and ER residence time. PERRC allows precise control over the stringency of protease evolution by adjusting counterselection to selection substrate ratios. Using PERRC, we evolved an orthogonal tobacco etch virus protease variant, TEVESNp, that selectively cleaves a substrate (ENLYFES) that differs by only one amino acid from its parent sequence (ENLYFQS). TEVESNp exhibits a remarkable 65-fold preference for the evolved substrate, marking the first example of an engineered orthogonal protease driven by such a slight difference in substrate recognition. Furthermore, TEVESNp functions as a competent protease for constructing orthogonal protein circuits in bacteria, and molecular dynamic simulations analysis reveals subtle yet functionally significant active site rearrangements. PERRC is a modular dual-substrate display system that facilitates precise engineering of protease specificity.

synthetic biology↗

bioRxiv2023

A comprehensive survey of coronaviral main protease active site diversity in 3D: Identifying and analyzing drug discovery targets in search of broad specificity inhibitors for the next coronavirus pandemic

Although the rapid development of therapeutic responses to combat SARS-CoV-2 represents a great human achievement, it also demonstrates untapped potential for advanced pandemic preparedness. Cross-species efficacy against multiple human coronaviruses by the main protease (MPro) inhibitor nirmatrelvir raises the question of its breadth of inhibition and our preparedness against future coronaviral threats. Herein, we describe sequence and structural analyses of 346 unique MPro enzymes from all coronaviruses represented in the NCBI Virus database. Cognate substrates of these representative proteases were inferred from their polyprotein sequences. We clustered MPro sequences based on sequence identity and AlphaFold2-predicted structures, showing approximate correspondence with known viral subspecies. Predicted structures of five representative MPros bound to their inferred cognate substrates showed high conservation in protease:substrate interaction modes, with some notable differences. Yeast-based proteolysis assays of the five representatives were able to confirm activity of three on inferred cognate substrates, and demonstrated that of the three, only one was effectively inhibited by nirmatrelvir. Our findings suggest that comprehensive preparedness against future potential coronaviral threats will require continued inhibitor development. Our methods may be applied to candidate coronaviral MPro inhibitors to evaluate in advance the breadth of their inhibition and identify target coronaviruses potentially meriting advanced development of alternative countermeasures.

molecular biology↗