Novel phosphotransferase system genes revealed by genome analysis - the complete complement of PTS proteins encoded within the genome of Bacillus subtilis

Bacillus subtilis can utilize several sugars as single sources of carbon an d energy. Many of these sugars are transported and concomitantly phosphoryl ated by the phosphoenolpyruvate : sugar phosphotransferase system (PTS). In addition to its role in sugar uptake, the PTS is one of the major signal t ransduction systems in B. subtilis. In this study, an analysis of the compl ete set of PTS proteins encoded within the B. subtilis genome is presented, Fifteen sugar-specific PTS permeases were found to be present and the func tions of novel PTS permeases were studied based on homology to previously c haracterized permeases, analysis of the structure of the gene clusters in w hich the permease encoding genes are located and biochemical analysis of re levant mutants. Members of the glucose, sucrose, lactose, mannose and fruct ose/mannitol families of PTS permeases were identified. Interestingly, nine pairs of IIB and IIC domains belonging to the glucose and sucrose permease families are present in B. subtilis; by contrast only five Enzyme IIA(Glc) -like proteins or domains are encoded within the B. subtilis genome. Conseq uently, some of the EIIA(Glc)-like proteins must function in phosphoryl tra nsfer to more than on IIB domain of the glucose and sucrose families. In ad dition, 13 PTS-associated proteins are encoded within the B. subtilis genom e. These proteins include metabolic enzymes, a bifunctional protein kinase/ phosphatase, a transcriptional cofactor and transcriptional regulators that are involved in PTS-dependent signal transduction. The PTS proteins and th e auxilliary PTS proteins represent a highly integrated network that cataly ses and simultaneously modulates carbohydrate utilization in this bacterium .