Arsenite oxidation by a chemoautotrophic moderately acidophilic Thiomonas sp.: from the strain isolation to the gene study.
An autotrophic bacterium able to gain energy from the oxidation of arsenite was isolated from arsenite-containing acid mine drainage waters. It belongs to the genus Thiomonas as shown by DNA-DNA hybridization experiments, 16S rRNA gene sequence, quinone and fatty acid content analyses. Carboxysomes were observed and the cbbSL genes encoding the ribulose 1,5-bisphosphate carboxylase/oxygenase were detected, confirming that this bacterium is able to fix CO(2). Arsenite oxidation was catalysed by a membrane-bound enzyme, and this activity was detected essentially in cells grown in the presence of arsenite. The genes encoding the two subunits of the arsenite oxidase of the Thiomonas isolate have been sequenced. The small subunit has a characteristic Tat signal sequence and contains the residues binding the [2Fe-2S] Rieske-type cluster. The large subunit has the [3Fe-4S] cluster-binding motif as well as the residues proposed to bind arsenite. In addition, most of the residues interacting with the molybdenum cofactor are conserved. The genes encoding both subunits belong to an operon, likely with a gene encoding a cytochrome c. The expression of this operon is greater in cells grown in the presence than in the absence of arsenite, in agreement with a transcriptional regulation in the presence of this metalloid.
Duquesne
Katia
K
CNRS, Institut de Biologie Structurale et de Microbiologie, Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Marseille, France.
Lieutaud
Aurélie
A
Ratouchniak
Jeanine
J
Muller
Daniel
D
Lett
Marie-Claire
MC
Bonnefoy
Violaine
V
D018053:Arsenites / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D042521:Burkholderiaceae / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D052837:Chemoautotrophic Growth; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005798:Genes, Bacterial; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009876:Operon; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D018053:Arsenites; D012336:RNA, Ribosomal, 16S; D010088:Oxidoreductases; C078179:arsenite oxidase; C015001:arsenite