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Nmr structure of catabolite activator protein in the unliganded stateNmr structure of catabolite activator protein in the unliganded state
Structural highlights
Function[CRP_ECO57] A global transcription regulator. Complexes with cyclic AMP (cAMP) which allosterically activates DNA binding to regulate transcription. It can act as an activator, repressor, coactivator or corepressor. Induces a severe bend in DNA. Acts as a negative regulator of its own synthesis as well as for adenylate cyclase (cyaA), which generates cAMP. Plays a major role in carbon catabolite repression (CCR) (By similarity). Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe cAMP-mediated allosteric transition in the catabolite activator protein (CAP; also known as the cAMP receptor protein, CRP) is a textbook example of modulation of DNA-binding activity by small-molecule binding. Here we report the structure of CAP in the absence of cAMP, which, together with structures of CAP in the presence of cAMP, defines atomic details of the cAMP-mediated allosteric transition. The structural changes, and their relationship to cAMP binding and DNA binding, are remarkably clear and simple. Binding of cAMP results in a coil-to-helix transition that extends the coiled-coil dimerization interface of CAP by 3 turns of helix and concomitantly causes rotation, by approximately 60 degrees , and translation, by approximately 7 A, of the DNA-binding domains (DBDs) of CAP, positioning the recognition helices in the DBDs in the correct orientation to interact with DNA. The allosteric transition is stabilized further by expulsion of an aromatic residue from the cAMP-binding pocket upon cAMP binding. The results define the structural mechanisms that underlie allosteric control of this prototypic transcriptional regulatory factor and provide an illustrative example of how effector-mediated structural changes can control the activity of regulatory proteins. Structural basis for cAMP-mediated allosteric control of the catabolite activator protein.,Popovych N, Tzeng SR, Tonelli M, Ebright RH, Kalodimos CG Proc Natl Acad Sci U S A. 2009 Apr 9. PMID:19359484[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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