A5066685728- Bacterial Genetics and Biotechnology
- Lipid Membrane Structure and Behavior
- RNA and protein synthesis mechanisms
- Ion channel regulation and function
- Antimicrobial Peptides and Activities
- Bacteriophages and microbial interactions
- Nanopore and Nanochannel Transport Studies
- Cardiac electrophysiology and arrhythmias
- Antibiotic Resistance in Bacteria
- Clostridium difficile and Clostridium perfringens research
- Mycobacterium research and diagnosis
- Muscle Physiology and Disorders
- Mitochondrial Function and Pathology
- Aquaculture disease management and microbiota
- Biochemical and Structural Characterization
- RNA Interference and Gene Delivery
- Enzyme Structure and Function
- Chronic Obstructive Pulmonary Disease (COPD) Research
- Fungal Biology and Applications
- Invertebrate Immune Response Mechanisms
- Insect and Pesticide Research
- Cardiomyopathy and Myosin Studies
- Polydiacetylene-based materials and applications
- Advanced biosensing and bioanalysis techniques
- Metabolism and Genetic Disorders
Inserm
2014-2025
Centre National de la Recherche Scientifique
2005-2025
Université de Montpellier
2008-2025
Physiologie et Médecine Expérimentale du Coeur et des Muscles
2017-2022
Seascape Consultants (United Kingdom)
2020
Caterpillar (United States)
2020
Centre Hospitalier Universitaire de Montpellier
2016
Hôpital Arnaud de Villeneuve
2014
Centre de Biologie Structurale
2003-2010
Université de Lille
2007
In Gram-negative bacteria and eukaryotic organelles, beta-barrel proteins of the outer membrane protein 85-two-partner secretion B (Omp85-TpsB) superfamily are essential components transport machineries. The TpsB transporter FhaC mediates Bordetella pertussis filamentous hemagglutinin (FHA). We report 3.15 A crystal structure FhaC. comprises a 16-stranded beta barrel that is occluded by an N-terminal alpha helix extracellular loop periplasmic module composed two aligned...
The small membrane protein p7 of hepatitis C virus forms oligomers and exhibits ion channel activity essential for infectivity. These viroporin features render an attractive target antiviral drug development. In this study, from strain HCV-J (genotype 1b) was chemically synthesized purified measurements structure analyses. cation-selective channels in planar lipid bilayers at the single-channel level by patch clamp technique. Ion shown to be inhibited hexamethylene amiloride but not...
Significance Ventilator-induced diaphragmatic dysfunction (VIDD) refers to the diaphragm muscle weakness that follows prolonged controlled mechanical ventilation, impeding recovery from respiratory failure. The mechanisms underlying VIDD are still not fully understood. Using human samples and murine models of VIDD, we identify here a pathophysiological pathway involving structural functional impairment ryanodine receptor (RyR1), main sarcoplasmic reticulum (SR) Ca 2+ release channel. We...
In Enterobacter aerogenes , multidrug resistance involves a decrease in outer membrane permeability associated with changes an as yet uncharacterized porin. We purified the major porin from wild‐type strain and resistant strain. characterized this porin, which was found to be OmpC/OmpF‐like protein analysed its pore‐forming properties lipid bilayers. The compared we observed (i) that single‐channel conductance 70% lower than of wild type; (ii) it three times more selective for cations; (iii)...
Piscidin, an antibacterial peptide isolated from the mast cells of striped bass, has potent antimicrobial activity against a broad spectrum pathogens in vitro. We investigated mechanism action this 22-residue cationic by carrying out structural studies and electrophysiological experiments lipid bilayers. Circular dichroism showed that piscidin was unstructured water but had high α-helix content dodecylphosphocholine (DPC) micelles. 1H NMR data TFE confirmed these results demonstrated segment...
How cells respond to mechanical forces by converting them into biological signals underlie crucial cellular processes. Our understanding of mechanotransduction has been hindered technical barriers, including limitations in our ability effectively apply low range piconewton specific mechanoreceptors on cell membranes without laborious and repetitive trials. To overcome these challenges we introduce the Nano-winch, a robust, easily assembled, programmable DNA origami-based molecular actuator....
A detergent‐solubilized fraction of skin mucus carp ( Cyprinus carpio ) induced ion channels after reconstitution into planar lipid bilayers. differential extraction using a non‐ionic detergent followed by electrophoretic separation led to the isolation two hydrophobic 31‐kDa and 27‐kDa proteins. In contrast protein, which was glycosylated, did not bind concanavalin A. The these proteins bilayer restored ionophore behavior already observed with crude mucus. main unit conductance levels were...
OmpF porin is a nonspecific pore protein from the outer membrane of Escherichia coli. Previously, set mutants was selected that allow passage long maltodextrins do not translocate through wild-type pore. Here, we describe crystal structures four point and one deletion mutant this set; their functional characterization reported in accompanying paper (Saint, N., Lou, K.-L., Widmer, C., Luckey, M., Schirmer, T., Rosenbusch, J. P. (1996) Biol. Chem. 271, 20676-20680). All mutations have local...
Inter-individual variability in muscle responses to mechanical stress during exercise is poorly understood. Therefore, new cell culture scaffolds are needed gain deeper insights into the cellular mechanisms underlying influence of on human myogenic progenitor cells behavior. To this end, we propose first vitro model involving uniaxial applied aligned primary muscle-derived cells, employing a biocompatible organic-inorganic photostructurable hybrid material (OIPHM) covalently attached...
Many virulence factors of pathogenic microorganisms are presented at the cell surface. However, protein secretion across outer membrane Gram-negative bacteria remains poorly understood. Here we used extremely efficient Bordetella pertussis filamentous hemagglutinin (FHA) to decipher this process. FHA requires a single specific accessory protein, FhaC, prototype family proteins necessary for extracellular localization various in bacteria. We show that FhaC is heat-modifiable and localized...
The partial N-terminal amino acid sequence of the antimicrobial peptide reported in present paper has been submitted to TrEMBL database under accession number P83338. A 6.7 kDa was isolated from trout skin secretions using extraction followed by cation-exchange chromatography, (t)C(18) solid-phase extraction, and C(18) reversed-phase HPLC. molecular mass this peptide, which is tentatively named oncorhyncin III, 6671 Da, as determined matrix-assisted laser-desorption ionization MS. sequencing...
Widespread in Gram-negative bacteria, the two-partner secretion (TPS) pathway mediates of large, β-helical 'TpsA' proteins with various functions. TpsA harbour a conserved, N-proximal TPS domain essential for secretion. TpsB transporters specifically recognize their partners periplasm and mediate translocation across outer membrane through hydrophilic channel. The FHA/FhaC pair Bordetella pertussis represents model system. FhaC is composed β barrel preceded by two periplasmic POTRA domains...
The Escherichia coli OmpF pore is governed by an internal constriction consisting of the negatively charged loop 3 folded into lumen and positively barrel wall located on opposite side across pore, 'anti-loop 3'. To investigate role anti-loop in solute diffusion, four site-directed mutations, K16A, K16D, R132A R132D, were introduced this eyelet region. mutant porins expressed efficiently inserted outer membrane, thermal stabilities resulting trimers determined. Diffusion cefepime, a recently...
Mechanosensitive (MS) ion channels have been documented in a variety of cells belonging to <i>Eukarya</i> and<i>Eubacteria</i>. We report the novel finding two types MS cell membrane halophilic archaeon<i>Haloferax volcanii</i>, member <i>Archaea</i>that comprise third phylogenetic domain. The channels, MscA1 and MscA2, differed their kinetic properties with exhibiting more frequent open-closed transitions than MscA2. Both large conductances that rectify between −40 mV +40 where conductance...
Many bioactive peptides, presenting an unstructured conformation in aqueous solution, are made resistant to degradation by posttranslational modifications. Here, we describe how molecular oligomerization solution can generate a still unknown transport form for amphipathic which is more compact and proteases than forms related any possible monomer. This phenomenon emerged from 3D structure, function, properties of distinctin, heterodimeric antimicrobial compound consisting two peptide chains...
The Escherichia coli OmpF pore is governed by an internal constriction consisting of the negatively charged loop 3 folded into lumen and positively barrel wall located on opposite side across pore, ‘anti-loop 3'. To investigate role anti-loop in solute diffusion, four site-directed mutations, K16A, K16D, R132A R132D, were introduced this eyelet region. mutant porins expressed efficiently inserted outer membrane, thermal stabilities resulting trimers determined. Diffusion cefepime, a recently...
Integral outer membrane transporters of the Omp85/TpsB superfamily mediate translocation proteins across, or their integration into, membranes Gram-negative bacteria, chloroplasts, and mitochondria. The Bordetella pertussis FhaC/FHA couple serves as a model for two-partner secretion pathway in with TpsB protein, FhaC, being specific transporter its TpsA partner, FHA, across membrane. In this work, we have investigated structure/function relationship FhaC by analyzing ion channel properties...