Mutations in Catabolite Control Protein CcpA Showing Glucose-Independent Regulation in Bacillus megaterium

We identified five single amino acid exchanges in CcpA that lead to permanent repression of the xylose utilization genes in the absence of glucose. Other proteins from the CcpA regulon also show glucose-independent regulation in the mutants. The mutant CcpA proteins bind to the DNA target catabolite responsive elements without the corepressor HPr-Ser-P.