Functional analysis of three sulfide:quinone oxidoreductase homologs in Chlorobaculum tepidum.

ABSTRACT: Sulfide:quinone oxidoreductase (SQR) catalyzes sulfide oxidation during sulfide-dependent chemo- and phototrophic growth in bacteria. The green sulfur bacterium Chlorobaculum tepidum (formerly Chlorobium tepidum) can grow on sulfide as the sole electron donor and sulfur source. C. tepidum contains genes encoding three SQR homologs: CT0117, CT0876, and CT1087. This study examined which, if any, of the SQR homologs possess sulfide-dependent ubiquinone reduction activity and are required for growth on sulfide. In contrast to CT0117 and CT0876, transcripts of CT1087 were detected only when cells actively oxidized sulfide. Mutation of CT0117 or CT1087 in C. tepidum decreased SQR activity in membrane fractions, and the CT1087 mutant could not grow with >or=6 mM sulfide. Mutation of both CT0117 a

SUBMITTER: Chan LK 

PROVIDER: S-EPMC2632091 | biostudies-literature | 2009 Feb

REPOSITORIES: biostudies-literature