3h3u | pdb_00003h3u
Crystal structure of CRP (cAMP receptor Protein) from Mycobacterium tuberculosis
Structural highlights
FunctionCRPL_MYCTU Global transcriptional regulator that complexes with cAMP and binds to specific DNA promoter sites, causing DNA-bending, to regulate transcription. cAMP improves binding to specific DNA sequences, probably by altering protein conformation. The CRP regulon is predicted to contain about 115 genes. Some genes are activated by CRP (rpfA, whiB1) while others are repressed (fadD10). There are 2 CRP-binding sites in the promoter of whiB1, at low concentrations of CRP with or without cAMP transcription of whiB1 is enhanced via site CRP1, then repressed as site CRP2 is filled.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCyclic AMP (cAMP) receptor protein, which acts as the sensor of cAMP levels in cells, is a well-studied transcription factor that is best known for allosteric changes effected by the binding of cAMP. Although genetic and biochemical data on the protein are available from several sources, structural information about the cAMP-free protein has been lacking. Therefore, the precise atomic events that take place upon binding of cAMP, leading to conformational changes in the protein and its activation to bind DNA, have been elusive. In this work we solved the cAMP-free crystal structure of the Mycobacterium tuberculosis homolog of cAMP receptor protein at 2.9 A resolution, and carried out normal-mode analysis to map conformational transitions among its various conformational states. In our structure, the cAMP-binding domain holds onto the DNA-binding domain via strong hydrophobic interactions, thereby freezing the latter in a conformation that is not competent to bind DNA. The two domains release each other in the presence of cAMP, making the DNA-binding domain more flexible and allowing it to bind its cognate DNA via an induced-fit mechanism. The structure of the cAMP-free protein and results of the normal-mode analysis therefore highlight an elegant mechanism of the allosteric changes effected by the binding of cAMP. Mapping conformational transitions in cyclic AMP receptor protein: crystal structure and normal-mode analysis of Mycobacterium tuberculosis apo-cAMP receptor protein.,Kumar P, Joshi DC, Akif M, Akhter Y, Hasnain SE, Mande SC Biophys J. 2010 Jan 20;98(2):305-14. PMID:20338852[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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