<p>The DMSO reductase family is a large and rapidly expanding group of enzymes found in bacteria and archaea that share a common form of molybdenum cofactor known as bis(molybdopterin guanine dinucleotide)Mo [<cite idref="PUB00042994"/>]. This entry represents the molybdopterin subunit, typically called the alpha subunit, found in various type II DMSO reductase family enzymes. These include two distinct but very closely related periplasmic proteins of anaerobic respiration; selenate reductase and chlorate reductase [<cite idref="PUB00042991"/>]. Other proteins containing this subunit include dimethyl sulphide dehydrogenase and ethylbenzene dehydrogenase [<cite idref="PUB00042992"/>, <cite idref="PUB00042993"/>]. This alpha subunit has a twin-arginine translocation (TAT) signal for Sec-independent translocation across the plasma membrane. </p>