title: Stable DNA opening within open promoter complexes is mediated by the RNA polymerase beta'-jaw domain.
abstract: DNA opening for transcription-competent open promoter complex (OC) formation by the bacterial RNA polymerase (RNAP) relies upon a complex network of interactions between the structurally conserved and flexible modules of the catalytic beta and beta'-subunits, RNAP-associated sigma-subunit, and the DNA. Here, we show that one such module, the beta'-jaw, functions to stabilize the OC. In OCs formed by the major sigma70-RNAP, the stabilizing role of the beta'-jaw is not restricted to any particular melted DNA segment. In contrast, in OCs formed by the major variant sigma54-RNAP, the beta'-jaw and a conserved sigma54 regulatory domain co-operate to stabilize the melted DNA segment immediately upstream of the transcription start site. Clearly, regulated communication between the mobile modules of the RNAP and the functional domain(s) of the sigma subunit is required for stable DNA opening.
authors.affiliation: Division of Biology, Faculty of Life Sciences, Sir Alexander Fleming Building, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Siva R
authors.initials: SR
authors.lastname: Wigneshweraraj
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Burrows
authors.forename: Konstantin
authors.initials: K
authors.lastname: Severinov
authors.forename: Martin
authors.initials: M
authors.lastname: Buck
mesh_terms: D017123:Bacteriophage T7 / Q000378:metabolism; D001665:Binding Sites; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004247:DNA / Q000737:chemistry*; D004269:DNA, Bacterial / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry*; D003850:Deoxyribonuclease I / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D015964:Gene Expression Regulation, Bacterial; D006493:Heparin / Q000737:chemistry; D008958:Models, Molecular; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011196:Potassium Permanganate / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013824:Thermus / Q000201:enzymology*; D013997:Time Factors; D014158:Transcription, Genetic
chemical_list: D003432:Cross-Linking Reagents; D004269:DNA, Bacterial; D011196:Potassium Permanganate; D006493:Heparin; D004247:DNA; D012321:DNA-Directed RNA Polymerases; D003850:Deoxyribonuclease I