| Modification Notes |
Escherichia coli contains more than 250 known promoters that must be activated prior to transcription. cAMP receptor protein (crp), also known as cAMP regulatory protein and catabolite gene activator, is a 210 amino acid E. coli protein that forms a complex with cyclic AMP and binds to specific DNA sites near the promoter, resulting in homodimeric transcription activation of more than a hundred E. coli promoters. Acting as a negative regulator against its own synthesis, crp regulates transcription of several catabolite-sensitive operons. Crp activates transcription by making multiple interactions with RNA polymerase. Containing one cyclic nucleotide binding domain and one HTH crp-type DNA binding domain, crp binds DNA as a dimer to induce a severe bend in the DNA. This formation is a regulatory mechanism of crp gene expression that plays a major role in determining the molecular mechanism in gene transcription. |