SEQUENCE AND FUNCTIONAL-ANALYSIS OF THE GENE ENCODING VIBRIO-CHOLERAECAMP RECEPTOR PROTEIN

We describe here the cloning, nucleotide sequence, and functional expr ession of the clp gene of Vibrio cholerae (Vc) encoding the cyclic AMP receptor protein (CRP). The Ve crp gene shows 81% identity with the c rp gene from Escherichia coli (Ec) and its deduced amino acid sequence shows 95% identity with the Ec protein. When expressed from inducible promoters, the cloned Ve gene produced an approximately 20-kDa protei n which complemented the carbohydrate-negative and growth-defective ph enotypes of both Ec and Ve crp mutants. In the Vc clp mutant, the clon ed crp gene also restored the normal repression of ToxR-regulated viru lence genes which occurs under certain environmental conditions. (C) 1 997 Elsevier Science B.V.