Structure of a complex of catabolite gene activator protein and cyclic AMP refined at 2.5 A resolution.
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Weber IT, Steitz TA
Structure of a complex of catabolite gene activator protein and cyclic AMP refined at 2.5 A resolution.
J Mol Biol. 1987 Nov 20;198(2):311-26.
- PubMed ID
- 2828639 [ View in PubMed]
- Abstract
The structure of a dimer of the Escherichia coli catabolite gene activator protein has been refined at 2.5 A resolution to a crystallographic R-factor of 20.7% starting with coordinates fitted to the map at 2.9 A resolution. The two subunits are in different conformations and each contains one bound molecule of the allosteric activator, cyclic AMP. The amino-terminal domain is linked to the smaller carboxy-terminal domain by a nine-residue hinge region that exists in different conformations in the two subunits, giving rise to approximately a 30 degree rotation between the positions of the small domains relative to the larger domains. The amino-terminal domain contains an antiparallel beta-roll structure in which the interstrand hydrogen bonding is well-determined. The beta-roll can be described as a long antiparallel beta-ribbon that folds into a right-handed supercoil and forms part of the cyclic AMP binding site. Each cyclic AMP molecule is in an anti conformation and has ionic and hydrogen bond interactions with both subunits.