Lien T, Birkeland N K
Department of Microbiology, University of Bergen, Jahnebakken 5, P.O. Box 7800, N-5020, Bergen, Norway.
FEMS Microbiol Lett. 2000 May 1;186(1):41-6. doi: 10.1111/j.1574-6968.2000.tb09079.x.
The genes encoding the desulforubidin type of dissimilatory sulfite reductase (Dsr) from the sulfate-reducing bacteria Desulfobacter vibrioformis and Desulfobulbus rhabdoformis were cloned and sequenced. Similar to the genes for dissimilatory sulfite reductase from the genera Archaeoglobus, Desulfovibrio and Desulfotomaculum the dsr genes were found to form an operon, dsrABD, where dsrA and dsrB encode the structural subunits, alpha and beta, of Dsr, respectively. dsrD encodes a conserved unknown protein apparently restricted to sulfate-reducing species. In Desulfobacter vibrioformis a fourth gene, designated dsrN, was found downstream of dsrD forming a contiguous operon, dsrABDN. DsrN showed significant sequence homology to cobyrinic a,c-diamide synthase, which is involved in the biosynthesis of vitamin B12. A function for DsrN in amidation of siroheme is likely. Analysis of the dsrAB-encoded proteins confirmed that the high conservation observed for other types of dissimilatory sulfite reductase is also found in desulforubidin. The use of Dsr sequences in unravelling the phylogeny of sulfate-reducing bacteria is discussed.
对来自硫酸盐还原菌脱硫弧菌属的弧状脱硫杆菌（Desulfobacter vibrioformis）和杆状脱硫球菌（Desulfobulbus rhabdoformis）中编码异化型亚硫酸盐还原酶（Dsr）的去硫红菌素类型的基因进行了克隆和测序。与来自嗜热栖热菌属、脱硫弧菌属和脱硫芽孢杆菌属的异化型亚硫酸盐还原酶基因相似，发现dsr基因形成一个操纵子dsrABD，其中dsrA和dsrB分别编码Dsr的结构亚基α和β。dsrD编码一种显然仅限于硫酸盐还原菌的保守未知蛋白。在弧状脱硫杆菌中，在dsrD下游发现了第四个基因，命名为dsrN，它与dsrD形成一个连续的操纵子dsrABDN。DsrN与参与维生素B12生物合成的钴胺素a，c - 二酰胺合酶具有显著的序列同源性。DsrN可能在西罗血红素的酰胺化中发挥作用。对dsrAB编码蛋白的分析证实，在去硫红菌素中也发现了其他类型异化型亚硫酸盐还原酶所具有的高度保守性。本文还讨论了利用Dsr序列来阐明硫酸盐还原菌的系统发育。
