Search

Your search keyword '"Monlezun, Laura"' showing total 25 results
Start Over Author "Monlezun, Laura"
25 results on '"Monlezun, Laura"'

14. ABC‐F translation factors: from antibiotic resistance to immune response.

Author

Fostier, Corentin R., Monlezun, Laura, Ousalem, Farès, Singh, Shikha, Hunt, John F., and Boël, Grégory

Subjects
*DRUG resistance in bacteria, *RIBOSOMES, *IMMUNE response, *BACTERIAL proteins, *PROTEIN synthesis, *PROKARYOTES, *TRANSLATIONS
Abstract

Energy‐dependent translational throttle A (EttA) from Escherichia coli is a paradigmatic ABC‐F protein that controls the first step in polypeptide elongation on the ribosome according to the cellular energy status. Biochemical and structural studies have established that ABC‐F proteins generally function as translation factors that modulate the conformation of the peptidyl transferase center upon binding to the ribosomal tRNA exit site. These factors, present in both prokaryotes and eukaryotes but not in archaea, use related molecular mechanisms to modulate protein synthesis for heterogenous purposes, ranging from antibiotic resistance and rescue of stalled ribosomes to modulation of the mammalian immune response. Here, we review the canonical studies characterizing the phylogeny, regulation, ribosome interactions, and mechanisms of action of the bacterial ABC‐F proteins, and discuss the implications of these studies for the molecular function of eukaryotic ABC‐F proteins, including the three human family members. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

17. New OprM structure highlighting the nature of the N-terminal anchor

Author

Monlezun, Laura, Phan, Gilles, Benabdelhak, Houssain, Lascombe, Marie-Bernard, Enguéné, Véronique, Picard, Martin, Broutin, Isabelle, Laboratoire de cristallographie et RMN biologiques (LCRB - UMR 8015), Centre National de la Recherche Scientifique (CNRS)-Université Paris Descartes - Paris 5 (UPD5), Système membranaires, photobiologie, stress et détoxication (SMPSD), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Université Paris Descartes - Paris 5 (UPD5)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
efflux pump, post-translational modification, multidrug resistance, [SDV]Life Sciences [q-bio], lipoyl, efflux pump, membrane protein, X-ray structure, Microbiology, Original Research
Abstract

International audience; Among the different mechanisms used by bacteria to resist antibiotics, active efflux plays a major role. In Gram-negative bacteria, active efflux is carried out by tripartite efflux pumps that form a macromolecular assembly spanning both membranes of the cellular wall. At the outer membrane level, a well-conserved outer membrane factor (OMF) protein acts as an exit duct, but its sequence varies greatly among different species. The OMFs share a similar tri-dimensional structure that includes a beta-barrel pore domain that stabilizes the channel within the membrane. In addition, OMFs are often subjected to different N-terminal post-translational modifications (PTMs), such as an acylation with a lipid. The role of additional N-terminal anchors is all the more intriguing since it is not always required among the OMFs family. Understanding this optional PTM could open new research lines in the field of antibiotics resistance. In Escherichia coli, it has been shown that CusC is modified with a tri-acylated lipid, whereas TolC does not show any modification. In the case of OprM from Pseudomonas aeruginosa, the N-terminal modification remains a matter of debate, therefore, we used several approaches to investigate this issue. As definitive evidence, we present a new X-ray structure at 3.8 Å resolution that was solved in a new space group, making it possible to model the N-terminal residue as a palmitoylated cysteine.

Published
2015
Full Text
View/download PDF

18. Tripartite assembly of RND multidrug efflux pumps

Author

Daury, Laetitia, primary, Orange, François, additional, Taveau, Jean-Christophe, additional, Verchère, Alice, additional, Monlezun, Laura, additional, Gounou, Céline, additional, Marreddy, Ravi K. R., additional, Picard, Martin, additional, Broutin, Isabelle, additional, Pos, Klaas M., additional, and Lambert, Olivier, additional

Published
2016
Full Text
View/download PDF

22. PpiA, a Surface PPIase of the Cyclophilin Family in Lactococcus lactis

Author

Trémillon, Nicolas, primary, Morello, Eric, additional, Llull, Daniel, additional, Mazmouz, Rabia, additional, Gratadoux, Jean-Jacques, additional, Guillot, Alain, additional, Chapot-Chartier, Marie-Pierre, additional, Monlezun, Laura, additional, Solé, Véronique, additional, Ginisty, Hervé, additional, and Poquet, Isabelle, additional

Published
2012
Full Text
View/download PDF

25. Multiple Mutations Lead to MexXY-OprM-Dependent Aminoglycoside Resistance in Clinical Strains of Pseudomonas aeruginosa

Author

Guénard, Sophie, Muller, Cédric, Monlezun, Laura, Benas, Philippe, Broutin, Isabelle, Jeannot, Katy, and Plésiat, Patrick

Abstract

ABSTRACTConstitutive overproduction of the pump MexXY-OprM is recognized as a major cause of resistance to aminoglycosides, fluoroquinolones, and zwitterionic cephalosporins in Pseudomonas aeruginosa. In this study, 57 clonally unrelated strains recovered from non-cystic fibrosis patients were analyzed to characterize the mutations resulting in upregulation of the mexXYoperon. Forty-four (77.2%) of the strains, classified as agrZmutants were found to harbor mutations inactivating the local repressor gene (mexZ) of the mexXYoperon (n= 33; 57.9%) or introducing amino acid substitutions in its product, MexZ (n= 11; 19.3%). These sequence variations, which mapped in the dimerization domain, the DNA binding domain, or the rest of the MexZ structure, mostly affected amino acid positions conserved in TetR-like regulators. The 13 remaining MexXY-OprM strains (22.8%) contained intact mexZgenes encoding wild-type MexZ proteins. Eight (14.0%) of these isolates, classified as agrW1mutants, overexpressed the gene PA5471, which codes for the MexZ antirepressor AmrZ, with 5 strains exhibiting growth defects at 37°C and 44°C, consistent with mutations impairing ribosome activity. Interestingly, one agrW1mutant appeared to harbor a 7-bp deletion in the coding sequence of the leader peptide, PA5471.1, involved in ribosome-dependent, translational attenuation of PA5471 expression. Finally, DNA sequencing and complementation experiments revealed that 5 (8.8%) strains, classified as agrW2mutants, harbored single amino acid variations in the sensor histidine kinase of ParRS, a two-component system known to positively control mexXYexpression. Collectively, these results demonstrate that clinical strains of P. aeruginosaexploit different regulatory circuitries to mutationally overproduce the MexXY-OprM pump and become multidrug resistant, which accounts for the high prevalence of MexXY-OprM mutants in the clinical setting.

Published
2013
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results