Modeling the cAMP-induced allosteric transition using the crystal structure of CAP-cAMP at 2.1 A resolution.
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Passner JM, Schultz SC, Steitz TA
Modeling the cAMP-induced allosteric transition using the crystal structure of CAP-cAMP at 2.1 A resolution.
J Mol Biol. 2000 Dec 15;304(5):847-59.
- PubMed ID
- 11124031 [ View in PubMed]
- Abstract
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.