1G6N: 2.1 Angstrom Structure Of Cap-camp

After an allosteric transition produced by the binding of cyclic AMP (cAMP), the Escherichia coli catabolite gene activator protein (CAP) binds DNA specifically and activates transcription. The three-dimensional crystal structure of the CAP-cAMP complex has been refined at 2.1 A resolution, thus enabling a better evaluation of the structural basis for CAP phenotypes, the interactions of cAMP with CAP and the roles played by water structure. A review of mutational analysis of CAP together with the additional structural information presented here suggests a possible mechanism for the cAMP-induced allostery required for DNA binding and transcriptional activation. We hypothesize that cAMP binding may reorient the coiled-coil C-helices, which provide most of the dimer interface, thereby altering the relative positions of the DNA-binding domains of the CAP dimer. Additionally, cAMP binding may cause a further rearrangement of the DNA-binding and cAMP-binding domains of CAP via a flap consisting of beta-strands 4 and 5 which lies over the cAMP.
PDB ID: 1G6NDownload
MMDB ID: 15043
PDB Deposition Date: 2000/11/7
Updated in MMDB: 2017/10
Experimental Method:
x-ray diffraction
Resolution: 2.1  Å
Source Organism:
Similar Structures:
Biological Unit for 1G6N: dimeric; determined by author and by software (PISA)
Molecular Components in 1G6N
Label Count Molecule
Proteins (2 molecules)
Catabolite Gene Activator Protein(Gene symbol: crp)
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB