Involved in activating dmsEABCD gene expression related to dimethyl sulfoxide (DMSO) reductase. Required for anaerobic respiration on dimethyl sulfoxide (DMSO). By anaerobical conditions and dimethyl sulfoxide (DMSO). Cells lacking this gene have no dimethyl sulfoxide (DMSO) reductase activity under aerobic, anaerobic without substrate, anaerobic with DMSO as substrate nor under anaerobic with nitrate as substrate conditions. Cells are not able to grow anaerobically by dimethyl sulfoxide (DMSO) respiration. DMSO does not activate transcription of the dmsEABCD genes induced by the anaerobic conditions. No effect on aerobical growth or growth under denitrifying conditions.