Identification of a gene encoding a tetrathionate hydrolase in Acidithiobacillus ferrooxidans.
Tetrathionate is one of the most important intermediates in dissimilatory sulfur oxidation and can itself be utilized as a sole energy source by some sulfur-oxidizing microorganisms. Tetrathionate hydrolase (4THase) plays a significant role in tetrathionate oxidation and should catalyze the initial step in the oxidative dissimilation when sulfur-oxidizing bacteria are grown on tetrathionate. 4THase activity was detected in tetrathionate-grown Acidithiobacillus ferrooxidans ATCC 23270 cells but not in iron-grown cells. A 4THase having a dimeric structure of identical 50kDa polypeptides was purified from tetrathionate-grown cells. The 4THase showed the maximum activity at pH 3.0 and high stability under acidic conditions. An open reading frame (ORF) encoding the N-terminal amino acid sequence of the purified 4THase was identified by a BLAST search using the database for the A. ferrooxidans ATCC 23270 genome. Heterologous expression of the gene in Escherichia coli resulted in the formation of inclusion bodies of the protein in an inactive form. Antisera against the recombinant protein clearly recognized the purified native 4THase, indicating that the ORF encoded the 4THase.
Kanao
Tadayoshi
T
Department of Instrumental Analysis, Advanced Science Research Center, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530, Japan. tkanao@cc.okayama-u.ac.jp
Kamimura
Kazuo
K
Sugio
Tsuyoshi
T
D042763:Acidithiobacillus / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D001709:Biotechnology; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D006867:Hydrolases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D020836:Protein Structure, Quaternary; D013045:Species Specificity; D013776:Tetrathionic Acid / Q000378:metabolism
D017931:DNA Primers; D004269:DNA, Bacterial; D013776:Tetrathionic Acid; D006867:Hydrolases; C104756:tetrathionate hydrolase