| Type: | Family | Name: | Arsenate reductase-like |
| Description: | Several bacterial taxon have a chromosomal resistance system, encoded by the ars operon, for the detoxification of arsenate, arsenite, and antimonite []. This system transports arsenite and antimonite out of the cell. The pump is composed of two polypeptides, the products of the arsA and arsB genes. This two-subunit enzyme produces resistance to arsenite and antimonite. Arsenate, however, must first be reduced to arsenite before it is extruded. A third gene, arsC, expands the substrate specificity to allow for arsenate pumping and resistance. ArsC is an approximately 150-residue arsenate reductase that uses reduced glutathione (GSH) to convert arsenate to arsenite with a redox active cysteine residue in the active site. ArsC forms an active quaternary complex with GSH, arsenate, and glutaredoxin 1 (Grx1). The three ligands must be present simultaneously for reduction to occur [].The arsC family also comprises the Spx proteins which are GRAM-positive bacterial transcription factors that regulate the transcription of multiple genes in response to disulphide stress [].The arsC protein structure has been solved []. It belongs to the thioredoxin superfamily fold which is defined by a beta-sheet core surrounded by alpha-helices. The active cysteine residue of ArsC is located in the loop between the first beta-strand and the first helix, which is also conserved in the Spx protein and its homologues. | Short Name: | Arsenate_reductase-like |
