Roles of CatR and cis,cis-muconate in activation of the catBC operon, which is involved in benzoate degradation in Pseudomonas putida

The mechanism by which CatR activates the catBC operon which encodes enzymes involved in benzoate degradation in Pseudomonas putida was examined. Gel shift studies demonstrated that the inducer, cis,cis-muconate, increases the binding affinity of CatR for the catBCpromoter region. In addition, cic,cis-muconate allows CatR to bind to a second site of the catBC promoter region, thereby activating catBC transcription. However, binding of CatR to this activation binding site required an intact repression binding site.