Abstract
The two-component system consisting of DmsS/DmsR is involved in the inductive expression of dmsCBA operon of Rhodobacter sphaeroides f. sp. denitrificans by DMSO (dimethyl sulfoxide) under anaerobic conditions. Sensor histidine kinase DmsS has no putative membrane-spanning hydrophobic amino acid regions, although other sensor proteins usually contain transmembrane region. Analysis of the transmembrane regions of DmsS by LacZ fusion showed it did not stick out to the periplasm.
In this study, we constructed and assayed the expression of dmsS-phoA
fusion genes. All of the strains showed no PhoA activity, suggesting that DmsS was located in the cytoplasm. These results indicated that the sensing domain of DmsS was located in the cytoplasm and DMSO in the cell is a transcriptional signal of dms operon.
