COMA, A PHOSPHORYLATED RESPONSE REGULATOR PROTEIN OF BACILLUS-SUBTILIS, BINDS TO THE PROMOTER REGION OF SRFA

ComA is a response regulator protein of Bacillus subtilis which is req uired for the transcription of several genes which are involved in lat e-growth expression and in responses to environmental stress. Among th ese genes are degQ, gsiA, and srfA. The last is an operon needed for t he development of genetic competence, surfactin production, and normal sporulation. We show here that partially purified ComA protein, isola ted from an overproducing Escherichia coli strain, is phosphorylated i n vitro by incubation with acetyl phosphate and that ComA could bind s pecifically to a DNA fragment containing the promoter of srfA and asso ciated sequences. The binding affinity is enhanced when ComA is phosph orylated. DNase I protection analysis identified two protected sites l ocated upstream from the srfA promoter. The presence of DNase I-hypers ensitive bonds induced by ComA binding which are located between the p rotected sequences is consistent with a model for ComA action involvin g the bending of DNA.