2cgp is a 3 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The 2.2 A resolution crystal structure of the Escherichia coli catabolite gene activator protein (CAP) complexed with cAMP and a 46-bp DNA fragment reveals a second cAMP molecule bound to each protein monomer. The second cAMP is in the syn conformation and is located on the DNA binding domain interacting with the helix-turn-helix, a beta-hairpin from the regulatory domain and the DNA (via water molecules). The presence of this second cAMP site resolves the apparent discrepancy between the NMR and x-ray data on the conformation of cAMP, and explains the cAMP concentration-dependent behaviors of the protein. In addition, this site's close proximity to mutations affecting transcriptional activation and its water-mediated interactions with a DNA recognition residue (E181) and DNA raise the possibility that this site has biological relevance.
The structure of a CAP-DNA complex having two cAMP molecules bound to each monomer.,Passner JM, Steitz TA Proc Natl Acad Sci U S A. 1997 Apr 1;94(7):2843-7. PMID:9096308[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑ Passner JM, Steitz TA. The structure of a CAP-DNA complex having two cAMP molecules bound to each monomer. Proc Natl Acad Sci U S A. 1997 Apr 1;94(7):2843-7. PMID:9096308