title: Structure of catabolite gene activator protein at 2.9 A resolution suggests binding to left-handed B-DNA.
abstract: The 2.9 A resolution crystal structure of Escherichia coli catabolite gene activator protein (CAP) complexed with cyclic AMP reveals two distinct structural domains separated by a cleft. The smaller carboxy-terminal domain is presumed to bind DNA while the amino-terminal domain is seen to bind cyclic AMP. Model building studies suggest that CAP binds to left-handed B-type DNA, contracting its major groove via two alpha-helices. It is possible that the CAP conversion of right- to left-handed DNA in a closed supercoil, is what activates transcription by RNA polymerase.
mesh_terms: D002352:Carrier Proteins; D000242:Cyclic AMP / Q000378:metabolism; D004247:DNA; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli; D046911:Macromolecular Substances; D009690:Nucleic Acid Conformation; D009876:Operon; D011485:Protein Binding; D011487:Protein Conformation; D011953:Receptors, Cyclic AMP / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D011953:Receptors, Cyclic AMP; D004247:DNA; D000242:Cyclic AMP; D012321:DNA-Directed RNA Polymerases