%0 Journal Article %A Grimm, Frauke %A Dobler, Nadine %A Dahl, Christiane %T Regulation of dsr genes encoding proteins responsible for the oxidation of stored sulfur in Allochromatium vinosum %D 2010 %J Microbiology, %V 156 %N 3 %P 764-773 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.034645-0 %I Microbiology Society, %X Sulfur globules are formed as obligatory intermediates during the oxidation of reduced sulfur compounds in many environmentally important photo- and chemolithoautotrophic bacteria. It is well established that the so-called Dsr proteins are essential for the oxidation of zero-valent sulfur accumulated in the globules; however, hardly anything is known about the regulation of dsr gene expression. Here, we present a closer look at the regulation of the dsr genes in the phototrophic sulfur bacterium Allochromatium vinosum. The dsr genes are expressed in a reduced sulfur compound-dependent manner and neither sulfite, the product of the reverse-acting dissimilatory sulfite reductase DsrAB, nor the alternative electron donor malate inhibit the gene expression. Moreover, we show the oxidation of sulfur to sulfite to be the rate-limiting step in the oxidation of sulfur to sulfate as sulfate production starts concomitantly with the upregulation of the expression of the dsr genes. Real-time RT-PCR experiments suggest that the genes dsrC and dsrS are additionally expressed from secondary internal promoters, pointing to a special function of the encoded proteins. Earlier structural analyses indicated the presence of a helix–turn–helix (HTH)-like motif in DsrC. We therefore assessed the DNA-binding capability of the protein and provide evidence for a possible regulatory function of DsrC. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.034645-0