Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9439900 | Research in Microbiology | 2005 | 8 Pages |
Abstract
The recently described anaerobic moderately halophilic bacterium Halanaerobium congolense has been shown to reduce thiosulfate and sulfur-but not sulfate-into sulfide. When cultivated in the presence of thiosulfate as terminal electron acceptor, H. congolense possesses a highly active thiosulfate:cyanide sulfur-transferase activity (rhodanese-like enzyme). A gene library of H. congolense (DSM 11287T) was constructed, and a 3.1-kb Sau3A DNA that encompassed a thiosulfate:cyanide sulfur-transferase-encoding gene was isolated in Escherichia coli. This fragment contains 2 orfs, which were separately subcloned in E. coli. The 900-bp gene encoding the rhodanese-like protein was named rdlA. RdlA differs from other known rhodanese-like proteins by having two potential catalytic sites, one N-terminal and one C-terminal, both harboring a cysteine. The two putative active sites are preceded by a highly-conserved region of unknown function. Closely related genes were also characterized in other thiosulfate-reducing non-sulfate-reducing anaerobes belonging to phylogenetically distant microorganisms, thus suggesting that RdlA is of importance in the mechanism of thiosulfate reduction by numerous members of the domain Bacteria.
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Authors
Gilles Ravot, Laurence Casalot, Bernard Ollivier, Gérard Loison, Michel Magot,