A gene cluster for chlorate metabolism in Ideonella dechloratans.
Chlorate reductase has been isolated from the chlorate-respiring bacterium Ideonella dechloratans, and the genes encoding the enzyme have been sequenced. The enzyme is composed of three different subunits and contains molybdopterin, iron, probably in iron-sulfur clusters, and heme b. The genes (clr) encoding chlorate reductase are arranged as clrABDC, where clrA, clrB, and clrC encode the subunits and clrD encodes a specific chaperone. Judging from the subunit composition, cofactor content, and sequence comparisons, chlorate reductase belongs to class II of the dimethyl sulfoxide reductase family. The clr genes are preceded by a novel insertion sequence (transposase gene surrounded by inverted repeats), denoted ISIde1. Further upstream, we find the previously characterized gene for chlorite dismutase (cld), oriented in the opposite direction. Chlorate metabolism in I. dechloratans starts with the reduction of chlorate, which is followed by the decomposition of the resulting chlorite to chloride and molecular oxygen. The present work reveals that the genes encoding the enzymes catalyzing both these reactions are in close proximity.
Thorell
Helena Danielsson
HD
Department of Chemistry, Karlstad University, SE 651 88 Karlstad, Sweden.
Stenklo
Katarina
K
Karlsson
Jan
J
Nilsson
Thomas
T
D000595:Amino Acid Sequence; D020562:Betaproteobacteria / Q000145:classification / Q000201:enzymology* / Q000235:genetics*; D002704:Chlorates / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D016254:Mutagenesis, Insertional; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D002704:Chlorates; D007527:Isoenzymes; D021122:Protein Subunits; D010088:Oxidoreductases; C021777:chlorate reductase