Cyclic AMP receptor proteins interacts with lactose operator DNA

The wildtype lac promoter-operator region of E. coli was reinvestigated for cyclic AMP receptor protein (CRP) binding sites using the 'footprinting' method. Two distinct interaction sites were found, one in the -60 base pair region, which has previously been described, and a second one covering the lac operator. These two sites are similar in extent, orientation and the characteristic pattern of CRP-induced DNaseI enhanced cutting sites.