title: Regulation of a novel Acidithiobacillus caldus gene cluster involved in metabolism of reduced inorganic sulfur compounds.
abstract: 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.
authors.affiliation: Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.
authors.forename: Olena I
authors.initials: OI
authors.lastname: Rzhepishevska
authors.forename: Jorge
authors.initials: J
authors.lastname: Valdés
authors.forename: Liucija
authors.initials: L
authors.lastname: Marcinkeviciene
authors.forename: Camelia Algora
authors.initials: CA
authors.lastname: Gallardo
authors.forename: Rolandas
authors.initials: R
authors.lastname: Meskys
authors.forename: Violaine
authors.initials: V
authors.lastname: Bonnefoy
authors.forename: David S
authors.initials: DS
authors.lastname: Holmes
authors.forename: Mark
authors.initials: M
authors.lastname: Dopson
mesh_terms: 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
chemical_list: D013440:Sulfides; D013457:Sulfur Compounds; D013885:Thiosulfates; C011342:pyrite; D013776:Tetrathionic Acid; D007501:Iron; D006867:Hydrolases; C104756:tetrathionate hydrolase