CHARACTERIZATION OF THE GENES ENCODING A RECEPTOR-LIKE HISTIDINE KINASE AND A COGNATE RESPONSE REGULATOR FROM A BIPHENYL POLYCHLOROBIPHENYL-DEGRADING BACTERIUM, RHODOCOCCUS SP STRAIN M5/

We report the cloning, sequence, and expression of the bpdS and bpdT g enes from Rhodococcus sp. strain MS, which are believed to encode the first two-component signal transduction system in the genus Rhodococcu s, which potentially regulates biphenyl/polychlorobiphenyl metabolism in M5. BpdT has a typical responses regulator sequence (209 amino acid s; 23 kDa), whereas BpdS, the predicted histidine kinase component, is an unusually large transmembrane protein (1,576 amino acids; 170 kDa) that contains ATP-binding and leucinerich repeat motifs and some cons erved residues of protein kinases. Expression of bpdST, like that of t he bpdC1C2BADE degradative operon, is inducible by biphenyl.