Abstract
In Rhodobacter sphaeroides f. sp. denitrificans, the DmsS/DmsR two-component signal transduction system regulates expression of dmsCBA operon encoding DMSO (dimethyl sulfoxide) respiration system. Although other sensor histidine kinase generally contains transmembrane region, LacZ analysis showed that the fusion proteins bound to the membrane from the cytoplasmic side. In the dmsA-deficient mutant which is not capable of DMSO respiration the amount of the dmsC-lacZ activity increased about 3-fold in the presence of DMS (dimethyl sulfide) and increased about 10-fold in the presence of DMSO. It is thought that DMS converted and a little DMSO generated in the media. These results indicated that DMS itself is not a signal and DMSO itself is a signal for the transcription of dmsCBA.
