Genes involved in hydrogen and sulfur metabolism in phototrophic sulfur bacteria

• Published in: FEMS microbiology letters 1999-11, Vol.180 (2), p.317-324
• Main Authors: Dahl, Christiane, Rákhely, Gábor, Pott-Sperling, A.S., Fodor, Barna, Takács, Mária, Tóth, András, Kraeling, Monika, Győrfi, Krisztina, Kovács, Ákos, Tusz, Jennifer, Kovács, Kornél L.
• Format: Article
• Language: English
• Subjects: Allochromatium vinosum; cytochrome b; dsrA gene; dsrK gene; dsrM gene; Heterodisulfide reductase; Heterologous hybridization; hydL gene; hydrogen; Hydrogenase; hydS gene; iron-sulfur protein; iron-sulfur proteins; Marichromatium; Purple sulfur bacterium; Sulfite reductase; Sulfur oxidation; Thiocapsa roseopersicina
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1016/S0378-1097(99)00500-5

The dsr genes and the hydSL operon are present as separate entities in phototrophic sulfur oxidizers of the genera Allochromatium, Marichromatium, Thiocapsa and Thiocystis and are organized similarly as in Allochromatium vinosum and Thiocapsa roseopersicina, respectively. The dsrA gene, encoding the α subunit of ‘reverse’ siroheme sulfite reductase, is also present in two species of green sulfur bacteria pointing to an important and universal role of this enzyme and probably other proteins encoded in the dsr locus in the oxidation of stored sulfur by phototrophic bacteria. The hupSL genes are uniformly present in the members of the Chromatiaceae family tested. The two genes between hydS and hydL encode a membrane-bound b-type cytochrome and a soluble iron-sulfur protein, respectively, resembling subunits of heterodisulfide reductase from methanogenic archaea. These genes are similar but not identical to dsrM and dsrK, indicating that the derived proteins have distinct functions, the former in hydrogen metabolism and the latter in oxidative sulfur metabolism.