title: Clostridium difficile has an original peptidoglycan structure with a high level of N-acetylglucosamine deacetylation and mainly 3-3 cross-links.
abstract: The structure of the vegetative cell wall peptidoglycan of Clostridium difficile was determined by analysis of its constituent muropeptides with a combination of reverse-phase high pressure liquid chromatography separation of muropeptides, amino acid analysis, mass spectrometry and tandem mass spectrometry. The structures assigned to 36 muropeptides evidenced several original features in C. difficile vegetative cell peptidoglycan. First, it is characterized by a strikingly high level of N-acetylglucosamine deacetylation. In addition, the majority of dimers (around 75%) contains A(2)pm(3) → A(2)pm(3) (A(2)pm, 2,6-diaminopimelic acid) cross-links and only a minority of the more classical Ala(4) → A(2)pm(3) cross-links. Moreover, a significant amount of muropeptides contains a modified tetrapeptide stem ending in Gly instead of D-Ala(4). Two L,D-transpeptidases homologues encoding genes present in the genome of C. difficile 630 and named ldt(cd1) and ldt(cd2), were inactivated. The inactivation of either ldt(cd1) or ldt(cd2) significantly decreased the abundance of 3-3 cross-links, leading to a marked decrease of peptidoglycan reticulation and demonstrating that both ldt(cd1)-and ldt(cd2)-encoded proteins have a redundant L,D-transpeptidase activity. The contribution of 3-3 cross-links to peptidoglycan synthesis increased in the presence of ampicillin, indicating that this drug does not inhibit the L,D-transpeptidation pathway in C. difficile.
authors.affiliation: Laboratoire G.R.A.M., EA 2656 IFR 23, Rouen University Hospital, 22 Boulevard Gambetta, 76183 Rouen Cedex, France.
authors.forename: Johann
authors.initials: J
authors.lastname: Peltier
authors.affiliation: Institut National de la Recherche Agronomique, UMR1319 Micalis, F-78350 Jouy-en-Josas, France, and; AgroParisTech, UMR Michalis, F-78350 Jouy-en-Josas, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Courtin
authors.affiliation: Laboratoire G.R.A.M., EA 2656 IFR 23, Rouen University Hospital, 22 Boulevard Gambetta, 76183 Rouen Cedex, France.
authors.forename: Imane
authors.initials: I
authors.lastname: El Meouche
authors.affiliation: Laboratoire G.R.A.M., EA 2656 IFR 23, Rouen University Hospital, 22 Boulevard Gambetta, 76183 Rouen Cedex, France.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Lemée
authors.affiliation: Institut National de la Recherche Agronomique, UMR1319 Micalis, F-78350 Jouy-en-Josas, France, and; AgroParisTech, UMR Michalis, F-78350 Jouy-en-Josas, France.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Chapot-Chartier
authors.affiliation: Laboratoire G.R.A.M., EA 2656 IFR 23, Rouen University Hospital, 22 Boulevard Gambetta, 76183 Rouen Cedex, France,. Electronic address: jean-louis.pons@univ-rouen.fr.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Pons
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016360:Clostridioides difficile / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016680:Genome, Bacterial / Q000502:physiology*; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010457:Peptidoglycan / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D010458:Peptidyl Transferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D010455:Peptides; D010457:Peptidoglycan; D010458:Peptidyl Transferases; D000117:Acetylglucosamine