title: Role of Helicobacter pylori methionine sulfoxide reductase in urease maturation.
abstract: The persistence of the gastric pathogen Helicobacter pylori is due in part to urease and Msr (methionine sulfoxide reductase). Upon exposure to relatively mild (21% partial pressure of O2) oxidative stress, a Δmsr mutant showed both decreased urease specific activity in cell-free extracts and decreased nickel associated with the partially purified urease fraction as compared with the parent strain, yet urease apoprotein levels were the same for the Δmsr and wild-type extracts. Urease activity of the Δmsr mutant was not significantly different from the wild-type upon non-stress microaerobic incubation of strains. Urease maturation occurs through nickel mobilization via a suite of known accessory proteins, one being the GTPase UreG. Treatment of UreG with H2O2 resulted in oxidation of MS-identified methionine residues and loss of up to 70% of its GTPase activity. Incubation of pure H2O2-treated UreG with Msr led to reductive repair of nine methionine residues and recovery of up to full enzyme activity. Binding of Msr to both oxidized and non-oxidized UreG was observed by cross-linking. Therefore we conclude Msr aids the survival of H. pylori in part by ensuring continual UreG-mediated urease maturation under stress conditions.
authors.affiliation: Department of Microbiology, University of Georgia, Athens, GA 30602, USA.
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Kuhns
authors.forename: Manish
authors.initials: M
authors.lastname: Mahawar
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Sharp
authors.forename: Stéphane
authors.initials: S
authors.lastname: Benoit
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Maier
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016480:Helicobacter pylori / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D051150:Methionine Sulfoxide Reductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D014510:Urease / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D006861:Hydrogen Peroxide; D051150:Methionine Sulfoxide Reductases; C027219:methionine sulfoxide reductase; D014510:Urease