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Etude fonctionnelle de Pmp23, une nouvelle enzyme de clivage du peptidoglycane chez Streptococcus pneumoniae

Abstract : The bacterial peptidoglycan is the major component of the cell wall and its integrity is essential to cell survival. Peptidoglycan biosynthesis during cell elongation and division is a regulated process requiring synthetases, the “Penicillin-Binding Proteins” and most probably hydrolytic enzymes. Comparison of bacterial genomes led to the identification of a new protein domain present only in Gram-positive bacteria: the PECACE domain (PEptidoglycan CArbohydrate Cleavage Enzyme). The predicted three-dimensional fold of this domain is analogous to the catalytic site of the lytic transglycosylase Slt70 from Escherichia coli and of the goose-type lysozyme ones. It probably catalyzes the peptidoglycan cleavage of the β(1-4) glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine residues of peptidoglycan. From the pathogenic bacteria Streptococcus pneumoniae, this domain is found in the extracellular region of a protein we called Pmp23 (Pneumococcal Membrane Protein). The recombinant form of this bitopic membrane protein of 23 kDa degrades bacterial extracts containing peptidoglycan. Bacteria with an inactivated pmp23 gene display a modification of their flocculation behaviour, are more sensitive to β-lactam antibiotics and present multiple and mislocalized septa. Taken together these observations indicate that Pmp23 is a hydrolase whose function is linked to peptidoglycan metabolism at the septum site.
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https://tel.archives-ouvertes.fr/tel-00012039
Contributor : Estelle Pagliero <>
Submitted on : Saturday, March 25, 2006 - 3:46:03 PM
Last modification on : Wednesday, November 4, 2020 - 2:30:01 PM
Long-term archiving on: : Friday, November 25, 2016 - 10:18:14 AM

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  • HAL Id : tel-00012039, version 1

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Estelle Pagliero. Etude fonctionnelle de Pmp23, une nouvelle enzyme de clivage du peptidoglycane chez Streptococcus pneumoniae. Biochimie [q-bio.BM]. Université Joseph-Fourier - Grenoble I, 2006. Français. ⟨tel-00012039⟩

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