CcpA mutants influence selective carbon source utilization by changing interactions with target genes in Bacillus licheniformis

The gram-positive bacterium Bacillus licheniformis exhibits obvious selective utilization on carbon sources. This process is mainly governed by the global regulator catabolite control protein A (CcpA), which can recognize and bind to multiple target genes that are widely distributed in metabolic pathways. Although DNA-binding domain of CcpA has been predicted, influence key amino acids gene recognition binding yet be uncovered. In this study, impact Lys31, Ile42 Leu56 vitro protein–DNA interactions vivo source was investigated. results showed alanine substitution Lys31 Ile42, located within 3rd helices domain, significantly weakened strength between genes. These mutations also lead alleviated repression xylose presence glucose. On other hand, Leu56Arg mutant 4th exhibited enhanced affinity compared with wild-type one. When used replace native one B. cells, glucose over increased. study provides a new strategy for understanding relationship function structure regulatory proteins. regulate beyond CCR engineering.