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Oxidative phosphorylation in a thermophilic, facultative chemoautotroph, H ydrogenophilus thermoluteolus , living prevalently in geothermal niches
Author(s) -
Wakai Satoshi,
Masanari Misa,
Ikeda Takumi,
Yamaguchi Naho,
Ueshima Saori,
Watanabe Kaori,
Nishihara Hirofumi,
Sambongi Yoshihiro
Publication year - 2013
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12005
Subject(s) - thermophile , oxidative phosphorylation , atp synthase , atpase , biochemistry , bioenergetics , biology , facultative , chemiosmosis , phosphorylation , chemistry , mitochondrion , enzyme , ecology
Summary H ydrogenophilus is a thermophilic, facultative chemoautotroph, which lives prevalently in high temperature geothermal niches. Despite the environmental distribution, little is known about its oxidative phosphorylation. Here, we show that inverted membrane vesicles derived from H ydrogenophilus thermoluteolus cells autotrophically cultivated with H 2 formed a proton gradient on the addition of succinate, dl ‐lactate, and NADH , and exhibited oxidation activity toward these three organic compounds. These indicate the capability of mixotrophic growth of this bacterium. Biochemical analysis demonstrated that the same vesicles contained an F ‐type ATP synthase. The F 1 sector of the ATP synthase purified from H . thermoluteolus membranes exhibited optimal ATPase activity at 65°C. Transformed E scherichia coli membranes expressing H . thermoluteolus F ‐type ATP synthase exhibited the same temperature optimum for the ATPase . These findings shed light on H . thermoluteolus oxidative phosphorylation from the aspects of membrane bioenergetics and ATPase biochemistry, which must be fundamental and advantageous in the biogeochemical cycles occurred in the high temperature geothermal niches.