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Ars operon
In molecular biology, the ars operon is an operon found in several bacterial taxon. It is required 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. ==ArsA and ArsB==
ArsA and ArsB form an anion-translocating ATPase. The ArsB protein is distinguished by its overall hydrophobic character, in keeping with its role as a membrane-associated channel. Sequence analysis reveals the presence of 13 putative transmembrane (TM) regions.
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Ars operon」の詳細全文を読む
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