A5061709927- Bacterial Genetics and Biotechnology
- RNA and protein synthesis mechanisms
- Bacteriophages and microbial interactions
- Antibiotic Resistance in Bacteria
- Enzyme Structure and Function
- Carbohydrate Chemistry and Synthesis
- Glycosylation and Glycoproteins Research
- Genomics and Phylogenetic Studies
- Probiotics and Fermented Foods
- Endoplasmic Reticulum Stress and Disease
- Photosynthetic Processes and Mechanisms
- Escherichia coli research studies
- Protein Structure and Dynamics
- Lipid Membrane Structure and Behavior
- Plant biochemistry and biosynthesis
- ATP Synthase and ATPases Research
- Lipid metabolism and biosynthesis
- Plant-Microbe Interactions and Immunity
- Plant Pathogenic Bacteria Studies
- Microbial Metabolites in Food Biotechnology
- Vibrio bacteria research studies
- Cancer therapeutics and mechanisms
- Legume Nitrogen Fixing Symbiosis
- Alkaline Phosphatase Research Studies
- Chromium effects and bioremediation
Université Paris-Saclay
2016-2023
CEA Paris-Saclay
2016-2023
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2016-2023
Centre National de la Recherche Scientifique
2012-2023
Institut de Biologie Intégrative de la Cellule
2015-2023
Université Paris-Sud
2008-2022
Centre Hospitalier d'Orsay
2021
Institut de Biochimie et Biophysique Moléculaire et Cellulaire
2008-2014
Aix-Marseille Université
2010
Université de Rennes
2000-2004
Summary The major Escherichia coli multidrug efflux pump AcrAB–TolC expels a wide range of antibacterial agents. Using in vivo cross‐linking, we show for the first time that antiporter AcrB and adaptor AcrA, which form translocase inner membrane, interact with outer membrane TolC exit duct to contiguous proteinaceous complex spanning bacterial cell envelope. Assembly appeared be constitutive, occurring presence absence drug substrate. This contrasts substrate‐induced assembly closely related...
Osmoprotectants exogenously supplied to a hyperosmotic culture medium are efficiently imported and amassed by stressed cells of <i>Escherichia coli</i>. In addition their evident role in the recovery maintenance osmotic balance, these solutes should play an important on behavior cellular macromolecules, for example process protein folding. Using random chemical mutagenesis approach, conditional lysine auxotrophic mutant was obtained. The growth this restored either or osmoprotectants...
Summary One‐third of the lipid A found in Escherichia coli outer membrane contains an unsubstituted diphosphate unit at position 1 (lipid 1‐diphosphate). We now report inner enzyme, LpxT (YeiU), which specifically transfers a phosphate group to A, forming 1‐diphosphate species. 32 P‐labelled obtained from lpxT mutants do not produce 1‐diphosphate. In vitro assays with Kdo 2 ‐[4′‐ P]lipid as acceptor shows that uses undecaprenyl pyrophosphate substrate donor. Inhibition formation wild‐type...
Colicin M was earlier demonstrated to provoke Escherichia coli cell lysis via inhibition of wall peptidoglycan (murein) biosynthesis. As the formation O-antigen moiety lipopolysaccharides concomitantly blocked, it hypothesized that metabolism undecaprenyl phosphate, an essential carrier lipid shared by these two pathways, should be target this colicin. However, exact and mechanism action colicin unknown. now purified near homogeneity, its effects on reinvestigated. It is exhibits both in...
Summary The gene cluster pbrTRABCD from Cupriavidus metallidurans CH34 is thought to encode a unique, specific resistance mechanism for lead. However, the exact functions of these genes are unknown. In this study we examine metal specificity and pbrABCD by expressing in different combinations comparing their ability restore Pb 2+ , Zn Cd metal‐sensitive C. strain DN440. We show that lead achieved through cooperation Zn/Cd/Pb‐translocating ATPase PbrA undecaprenyl pyrophosphate phosphatase...
ABSTRACT Genes encoding proteins that exhibit similarity to the C-terminal domain of Escherichia coli colicin M were identified in genomes some Pseudomonas species, namely, P. aeruginosa, syringae , and fluorescens . These genes detected only a restricted number strains. In aeruginosa for instance, homologue gene was located within ExoU-containing genomic island A, large horizontally acquired genetic element virulence determinant. Here we report cloning these from three species purification...
Abstract As a protective envelope surrounding the bacterial cell, peptidoglycan sacculus is site of vulnerability and an antibiotic target. Peptidoglycan components, assembled in cytoplasm, are shuttled across membrane cycle that uses undecaprenyl-phosphate. A product synthesis, undecaprenyl-pyrophosphate, converted to undecaprenyl-phosphate for reuse by integral pyrophosphatase, BacA. To understand how BacA functions, we determine its crystal structure at 2.6 Å resolution. The enzyme open...
Summary Outer membrane intimin directs attachment of enteropathogenic Escherichia coli (EPEC) via its Tir receptor in mammalian target cell membranes. Phosphorylation triggers local actin polymerization and the formation ‘pedestal‐like’ pseudopods. We demonstrate that protein contains three domains, a flexible N‐terminus (residues 40–188), central membrane‐integrated β‐barrel (189–549), tightly folded Tir‐binding domain (550–939). Intimin was shown by electron microscopy to form ring‐like...
Colicin M (ColM) is the only enzymatic colicin reported to date that inhibits cell wall peptidoglycan biosynthesis. It catalyzes specific degradation of lipid intermediates involved in this pathway, thereby provoking lysis susceptible Escherichia coli cells. A gene encoding a homologue ColM was detected within exoU-containing genomic island carried by certain pathogenic Pseudomonas aeruginosa strains. This bacteriocin (pyocin) we have named PaeM crystallized, and its structure with without...
Several integral membrane proteins exhibiting undecaprenyl-pyrophosphate (C55-PP) phosphatase activity were previously identified in Escherichia coli that belonged to two distinct protein families: the BacA protein, which accounts for 75% of C55-PP detected E. cell membranes, and three members PAP2 phosphatidic acid family, namely PgpB, YbjG LpxT. This dephosphorylation step is required provide C55-P carrier lipid plays a central role biosynthesis various wall polymers. We here report...
Colicin M inhibits Escherichia coli peptidoglycan synthesis through cleavage of its lipid-linked precursors. It has a compact structure, whereas other related toxins are organized in three independent domains, each devoted to particular function: translocation the outer membrane, receptor binding, and toxicity, from N C termini, respectively. To establish whether colicin displays such an organization despite structural characteristics, protein dissection experiments were performed, which...
Peptidoglycan (PG) is an essential constituent of the bacterial cell wall. During division, machinery responsible for PG synthesis localizes mid-cell, at septum, under control a multiprotein complex called divisome. In
Undecaprenyl phosphate (C55-P) is an essential 55-carbon long-chain isoprene lipidinvolved in the biogenesis of bacterial cell wall carbohydrate polymers: peptidoglycan, O antigen, teichoic acids, and other surface polymers. It functions as a lipid carrier that allows traffic sugar intermediates across plasma membrane, towards periplasm,where polymerization different cellwall components occurs. At end these processes, released pyrophosphate form (C55-PP). C55-P arises from dephosphorylation...
Colicin M (ColM), which is produced by some Escherichia coli strains to kill competitor from the same or related species, was recently shown inhibit cell wall peptidoglycan biosynthesis through enzymatic degradation of its lipid II precursor. ColM-producing are protected toxin that they produce coexpression a specific immunity protein, named Cmi, whose mode action still remains be identified. We report here resolution crystal structure composed four β strands and α helices. This rather...
Colicin M (ColM) is a bactericidal protein that kills sensitive cells by hydrolyzing lipid II, involved in the biosynthesis of cell wall peptidoglycan. It recognizes FhuA on outer leaflet, and its translocation through membrane depends energized Ton complex inner membrane. To be active periplasm, ColM must translocated then interact with FkpA, periplasmic exhibits both cis- trans-peptidylprolyl isomerase (PPiase) chaperon activities. In an attempt to directly target periplasm producing...
Colicins are proteins produced by some strains of Escherichia coli to kill competitors belonging the same species. Among them, ColM (colicin M) is only one that blocks biosynthesis peptidoglycan, a specific bacterial cell-wall polymer essential for cell integrity. acts in periplasm hydrolysing phosphoester bond peptidoglycan lipid intermediate (lipid II). cytotoxicity dependent on FkpA targeted cell, chaperone with peptidylprolyl cis–trans isomerase activity. Dissection was used delineate...
The biogenesis of bacterial cell-envelope polysaccharides requires the translocation, across plasma membrane, sugar sub-units that are produced inside cytoplasm. To this end, hydrophilic sugars anchored to a lipid phosphate carrier (undecaprenyl (C55-P)), yielding membrane intermediates which translocated outer face membrane. Finally, glycan moiety is transferred nascent acceptor polymer, releasing in "inactive" undecaprenyl pyrophosphate (C55-PP) form. Thus, C55-P generated through...
Peptidoglycan (PG) is an essential polymer of the bacterial cell wall and a major antibacterial target. Its synthesis requires glycosyltransferase (GTase) transpeptidase enzymes that, respectively, catalyze glycan chain elongation their cross-linking to form protective sacculus cell. The GTase domain bifunctional penicillin-binding proteins (PBPs) class A, such as Escherichia coli PBP1b, belong 51 family. These play role in PG synthesis, specific inhibition by moenomycin was shown lead...