Regulation of a novel Acidithiobacillus caldus gene cluster involved in metabolism of reduced inorganic sulfur compounds.
Acidithiobacillus caldus has been proposed to play a role in the oxidation of reduced inorganic sulfur compounds (RISCs) produced in industrial biomining of sulfidic minerals. Here, we describe the regulation of a new cluster containing the gene encoding tetrathionate hydrolase (tetH), a key enzyme in the RISC metabolism of this bacterium. The cluster contains five cotranscribed genes, ISac1, rsrR, rsrS, tetH, and doxD, coding for a transposase, a two-component response regulator (RsrR and RsrS), tetrathionate hydrolase, and DoxD, respectively. As shown by quantitative PCR, rsrR, tetH, and doxD are upregulated to different degrees in the presence of tetrathionate. Western blot analysis also indicates upregulation of TetH in the presence of tetrathionate, thiosulfate, and pyrite. The tetH cluster is predicted to have two promoters, both of which are functional in Escherichia coli and one of which was mapped by primer extension. A pyrrolo-quinoline quinone binding domain in TetH was predicted by bioinformatic analysis, and the presence of an o-quinone moiety was experimentally verified, suggesting a mechanism for tetrathionate oxidation.
Rzhepishevska
Olena I
OI
Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.
Valdés
Jorge
J
Marcinkeviciene
Liucija
L
Gallardo
Camelia Algora
CA
Meskys
Rolandas
R
Bonnefoy
Violaine
V
Holmes
David S
DS
Dopson
Mark
M
D042763:Acidithiobacillus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D015153:Blotting, Western; D019295:Computational Biology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D023061:Gene Order; D005798:Genes, Bacterial / Q000235:genetics*; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism; D007501:Iron / Q000494:pharmacology; D008969:Molecular Sequence Data; D005810:Multigene Family; D009876:Operon; D010084:Oxidation-Reduction / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013440:Sulfides / Q000494:pharmacology; D013457:Sulfur Compounds / Q000378:metabolism*; D013776:Tetrathionic Acid / Q000378:metabolism / Q000494:pharmacology; D013885:Thiosulfates / Q000494:pharmacology
D013440:Sulfides; D013457:Sulfur Compounds; D013885:Thiosulfates; C011342:pyrite; D013776:Tetrathionic Acid; D007501:Iron; D006867:Hydrolases; C104756:tetrathionate hydrolase