A5026229193- Lipid Membrane Structure and Behavior
- Bacterial Genetics and Biotechnology
- Antibiotic Resistance in Bacteria
- Ion channel regulation and function
- ATP Synthase and ATPases Research
- Ion Transport and Channel Regulation
- Photoreceptor and optogenetics research
- Mitochondrial Function and Pathology
- Metabolomics and Mass Spectrometry Studies
- Drug Transport and Resistance Mechanisms
- Protein Structure and Dynamics
- Cardiac electrophysiology and arrhythmias
- Mass Spectrometry Techniques and Applications
- Nanopore and Nanochannel Transport Studies
- Bacteriophages and microbial interactions
- Nitric Oxide and Endothelin Effects
- Neuroscience and Neuropharmacology Research
- Bacterial biofilms and quorum sensing
- Surfactants and Colloidal Systems
- Nanoparticle-Based Drug Delivery
- Innovative Microfluidic and Catalytic Techniques Innovation
- RNA Interference and Gene Delivery
- Clostridium difficile and Clostridium perfringens research
- Protein Kinase Regulation and GTPase Signaling
- Vanadium and Halogenation Chemistry
Laboratoire de Biologie Physico-Chimique des Protéines Membranaires
2004-2024
Université Paris Cité
2013-2024
Centre National de la Recherche Scientifique
2014-2024
Institut de Biologie Physico-Chimique
2011-2024
New York Psychoanalytic Society and Institute
2022
Columbia University
2022
Sorbonne Paris Cité
2017-2020
Université Paris Sciences et Lettres
2017-2020
Université Paris-Saclay
2019
CEA Paris-Saclay
2005-2019
Amphipols (APols) are short amphipathic polymers that can substitute for detergents to keep integral membrane proteins (MPs) water soluble. In this review, we discuss their structure and solution behavior; the way they associate with MPs; structure, dynamics, properties of resulting complexes. All MPs tested date form water-soluble complexes APols, biochemical stability is in general greatly improved compared detergent solutions. The functionality ligand-binding APol-trapped reviewed,...
Abstract Tripartite multidrug efflux systems of Gram-negative bacteria are composed an inner membrane transporter, outer channel and a periplasmic adaptor protein. They assumed to form ducts inside the periplasm facilitating drug exit across membrane. Here we present reconstitution native Pseudomonas aeruginosa MexAB–OprM Escherichia coli AcrAB–TolC tripartite Resistance Nodulation cell Division (RND) in lipid nanodisc system. Single-particle analysis by electron microscopy reveals protein...
Abstract Most membrane proteins studies require the use of detergents, but because lack a general, accurate and rapid method to quantify them, many uncertainties remain that hamper proper functional structural data analyses. To solve this problem, we propose based on matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) allows quantification pure or mixed detergents in complex with proteins. We validated wide variety automated process, thereby allowing routine for...
Abstract The tripartite multidrug efflux system MexAB-OprM is a major actor in Pseudomonas aeruginosa antibiotic resistance by exporting large variety of antimicrobial compounds. Crystal structures MexB and its Escherichia coli homolog AcrB had revealed asymmetric trimers depicting directional drug pathway conformational interconversion (from Loose Tight binding pockets to Open gate (LTO) for exit). It remains unclear how acquires LTO form. Here performing functional cryo-EM structural...
Antibiotic resistance is a major public health issue and many bacteria responsible for human infections have now developed variety of antibiotic mechanisms. For instance, Pseudomonas aeruginosa, disease-causing Gram-negative bacteria, resistant to almost every class antibiotics. Much this attributable multidrug efflux pumps, which are tripartite membrane protein complexes that span both membranes actively expel Here we report an in vitro procedure monitor transport by the MexAB-OprM pump. By...
Amphipols are amphipathic polymers designed to replace or supplement detergents in membrane protein solution studies. Previous work has suggested both advantages and disadvantages the use of a polyacrylate-based amphipol, A8−35, for studying sarcoplasmic reticulum Ca2+-ATPase (SERCA1a). We investigated this issue further using set four amphipols with different chemical structures. size exclusion chromatography experiments had shown that A8−35 SERCA1a/A8−35 complexes aggregate under certain...
How does the catalytic set-up of a hydrolase activate H2O2 for enzymatic oxidations? The oxidizing species is peracid, as these studies with metal-free haloperoxidases CPO-P and CPO-T clearly show. analogy between haloperoxidase reactions elucidated in below.
We describe an original activity assay for membrane transport that uses the proton motive force-dependent efflux pump MexAB from Pseudomonas aeruginosa. This is co-reconstituted into proteoliposomes together with bacteriorhodopsin (BR), a light-activated pump. In this system, upon illumination visible light, photo-induced gradient created by BR shown to be coupled active of substrates through
Molecular interactions are contingent upon the system's dimensionality. Notably, comprehending impact of dimensionality on protein-protein holds paramount importance in foreseeing protein behaviour across diverse scenarios, encompassing both solution and membrane environments. Here, we unravel among proteins various dimensionalities by quantifying their binding rates through fluorescence recovery experiments. Our findings presented examination two systems: streptavidin-biotin a complex...
Efflux pumps are membrane transporters that actively extrude various substrates, leading to multidrug resistance (MDR). In this study, we have designed a new test allows investigating the assembly of MexA-MexB-OprM efflux pump from Gram negative bacteria Pseudomonas aeruginosa. The method relies on streptavidin-mediated pull-down OprM proteoliposomes upon interaction with MexAB containing biotin function carried by lipids. We give clear evidence for importance MexA in promoting and...
By measuring the phosphorylation levels of individual proteolytic fragments SERCA1a separated by electrophoresis after their phosphorylation, we were able to study catalytic properties a p95C-p14N complex arising from cleavage proteinase K between Leu(119) and Lys(120), in loop linking A-domain with second transmembrane segment. ATP hydrolysis was very strongly inhibited, although ATP-dependent conversion ADP-sensitive E1P form E2P still occurred at appreciable rates. However, rate...
We document here the intrinsic fluorescence and 45Ca2+ binding properties of putative "E2P-related" complexes Ca2+-free ATPase with fluoride, formed in presence magnesium, aluminum, or beryllium. Intrinsic measurements suggest that absence inhibitors, complex beryllium fluoride (but not those magnesium aluminum fluoride) does constitute an appropriate analog "ADP-insensitive" phosphorylated form Ca2+-ATPase, so-called "E2P" state. measurements, performed 100 mm KCl, 5 Mg2+, 20% Me2SO at pH...
Crystalline forms of detergent-solubilized sarcoplasmic reticulum Ca2+-ATPase, obtained in the presence either a substrate analog, AMPPCP, or transition state complex, ADP·fluoroaluminate, were recently described to share same general architecture despite fact that, when studied test tube, these show different functional properties. Here, we that differences properties E1·AMPPCP and E1·ADP·AlFx membraneous (or solubilized) are much less pronounced examined 10 mm Ca2+ (the concentration...
Among the different mechanisms used by bacteria to resist antibiotics, active efflux plays a major role. In gram-negative bacteria, is carried out tripartite pumps that form macromolecular assembly spanning both membranes of cellular wall. At outer membrane level, well-conserved Outer Membrane Factor (OMF) protein acts as an exit duct, but its sequence varies greatly among species. The OMFs share similar tri-dimensional structure includes beta-barrel pore domain stabilizes channel within...
Ca2+-free crystals of sarcoplasmic reticulum Ca2+−ATPase have, up until now, been obtained in the presence inhibitors such as thapsigargin (TG), bound to transmembrane region this protein. Here, we examined consequences binding for We found that, after TG binding, an active site ligand beryllium fluoride can still bind ATPase and change conformation or dynamics cytosolic domains (as revealed by protection afforded against proteolysis), but it becomes unable induce any domain intrinsic...
Multidrug resistance has become a serious concern in the treatment of bacterial infections. A prominent role is ascribed to active efflux xenobiotics out bacteria by tripartite protein machinery. The mechanism drug extrusion rather well understood, thanks X-ray structures obtained for Escherichia coli TolC/AcrA/AcrB model system and related Pseudomonas aeruginosa OprM/MexA/MexB. However, many questions remain unresolved, particular stoichiometry pump assembly. On basis blue native...