PROSITE documentation PDOC51353 [for PROSITE entry PS51353]

Arsenate reductase arsC family profile

Several bacterial taxon have a chromosomal resistance system, encoded by the ars operon, for the detoxification of arsenate, arsenite, and antimonite [1]. This system transports arsenite and antimonite out of the cell. Arsenate, however, must first be reduced to arsenite before it is extruded. ArsC is an ~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 [2].

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 disulfide stress [3].

The arsC protein structure has been solved (see <PDB:1I9D>) [4]. It belongs to the thioredoxin superfamily fold which is defined by a β-sheet core surrounded by α-helices. The active cysteine residue of ArsC is located in the loop between the first β-strand and the first helix, which is also conserved in the Spx protein and its homologs.

The profile we developed covers the whole arsC conserved region.