title: Role of the N-Acetylmuramoyl-l-Alanyl Amidase, AmiA, of Helicobacter pylori in Peptidoglycan Metabolism, Daughter Cell Separation, and Virulence.
abstract: The human gastric pathogen, Helicobacter pylori, is becoming increasingly resistant to most available antibiotics. Peptidoglycan (PG) metabolism is essential to eubacteria, hence, an excellent target for the development of new therapeutic strategies. However, our knowledge on PG metabolism in H. pylori remains poor. We have further characterized an isogenic mutant of the amiA gene encoding a N-acetylmuramoyl-l-alanyl amidase. The amiA mutant displayed long chains of unseparated cells, an impaired motility despite the presence of intact flagella and a tolerance to amoxicillin. Interestingly, the amiA mutant was impaired in colonizing the mouse stomach suggesting that AmiA is a valid target in H. pylori for the development of new antibiotics. Using reverse phase high-pressure liquid chromatography, we analyzed the PG muropeptide composition and glycan chain length distribution of strain 26695 and its amiA mutant. The analysis showed that H. pylori lacked muropeptides with a degree of cross-linking higher than dimeric muropeptides. The amiA mutant was also characterized by a decrease of muropeptides carrying 1,6-anhydro-N-acetylmuramic acid residues, which represent the ends of the glycan chains. This correlated with an increase of very long glycan strands in the amiA mutant. It is suggested that these longer glycan strands are trademarks of the division site. Taken together, we show that the low redundancy on genes involved in PG maturation supports H. pylori as an actractive alternative model to study PG metabolism and cell shape regulation.
authors.affiliation: 1 Institut Pasteur, Unite de Pathogénie Bactérienne des Muqueuses , Paris, France .
authors.forename: Catherine
authors.initials: C
authors.lastname: Chaput
authors.affiliation: 1 Institut Pasteur, Unite de Pathogénie Bactérienne des Muqueuses , Paris, France .|2 Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne , Paris, France .|3 INSERM , Equipe Avenir, Paris, France .
authors.forename: Chantal
authors.initials: C
authors.lastname: Ecobichon
authors.affiliation: 1 Institut Pasteur, Unite de Pathogénie Bactérienne des Muqueuses , Paris, France .
authors.forename: Nadine
authors.initials: N
authors.lastname: Pouradier
authors.affiliation: 4 Institut Pasteur, Plate-forme de Protéomique, Paris, France .
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Rousselle
authors.affiliation: 4 Institut Pasteur, Plate-forme de Protéomique, Paris, France .
authors.forename: Abdelkader
authors.initials: A
authors.lastname: Namane
authors.affiliation: 1 Institut Pasteur, Unite de Pathogénie Bactérienne des Muqueuses , Paris, France .|2 Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne , Paris, France .|3 INSERM , Equipe Avenir, Paris, France .
authors.forename: Ivo G
authors.initials: IG
authors.lastname: Boneca
mesh_terms: D000581:Amidohydrolases / Q000235:genetics / Q000378:metabolism*; D000658:Amoxicillin / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D015870:Gene Expression; D016481:Helicobacter Infections / Q000188:drug therapy / Q000382:microbiology / Q000473:pathology*; D016480:Helicobacter pylori / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D051379:Mice; D008810:Mice, Inbred C57BL; D009112:Muramic Acids / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D010457:Peptidoglycan / Q000737:chemistry / Q000378:metabolism*; D013270:Stomach / Q000187:drug effects / Q000382:microbiology / Q000473:pathology; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D009112:Muramic Acids; D010457:Peptidoglycan; C430327:anhydro-N-acetylmuramic acid; D000658:Amoxicillin; D000581:Amidohydrolases