Regulation of a novel Acidithiobacillus caldus gene cluster involved in metabolism of reduced inorganic sulfur compounds

Olena I. Rzhepishevska, Jorge Valdés, Liucija Marcinkeviciene, Camelia Algora Gallardo, Rolandas Meskys, Violaine Bonnefoy, David S. Holmes, Mark Dopson

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)7367-7372
Number of pages6
JournalApplied and Environmental Microbiology
Volume73
Issue number22
DOIs
Publication statusPublished - Nov 2007

ASJC Scopus subject areas

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology

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