title: A respiratory-driven and an artificially driven ATP synthesis in mutants of Vibrio parahaemolyticus lacking H+-translocating ATPase.
abstract: Mutants of Vibrio parahaemolyticus lacking the H+-translocating ATPase were isolated to evaluate both the role of this enzyme and the possibility of the involvement of other cation-translocating ATPase in the energy transduction in this organism. Dicyclohexylcarbodiimide-sensitive ATPase activity which represents the H+-translocating ATPase was not detected either in the membrane vesicles or in the cytosol of the mutants. Three major subunits, alpha, beta and gamma, of the H+-translocating ATPase were missing in the membranes of the mutants. Although ATP was synthesized in wild type cells when an artificial H+ gradient was imposed, little ATP was synthesized in the mutants. However, we observed a large ATP synthesis driven by the respiration not only in the wild type but also in the mutants. The respiratory-driven ATP synthesis in wild type was inhibited by an H+ conductor, carbonylcyanide m-chlorophenylhydrazone, by about 50%. On the other hand, the ATP synthesis in the mutants was not affected by the H+ conductor. Since this organism possesses a respiratory Na+ pump, Na+-coupled ATP synthesis might take place. In fact, we observed some ATP synthesis driven by an artificially imposed Na+ gradient both in the wild type and the mutant.
authors.affiliation: Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sakai
authors.forename: C
authors.initials: C
authors.lastname: Moritani
authors.forename: M
authors.initials: M
authors.lastname: Tsuda
authors.forename: T
authors.initials: T
authors.lastname: Tsuchiya
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D009154:Mutation; D010085:Oxidative Phosphorylation; D010101:Oxygen Consumption; D006180:Proton-Translocating ATPases / Q000172:deficiency* / Q000378:metabolism; D012965:Sodium Chloride; D014736:Vibrio parahaemolyticus / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D012965:Sodium Chloride; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases