title: Conformational changes of Escherichia coli sigma54-RNA-polymerase upon closed-promoter complex formation.
abstract: RNA polymerase from the mesophile Escherichia coli exists in two forms, the core enzyme and the holoenzyme. Using cryo-electron microscopy and single-particle analysis, we have obtained the structure of the complete RNA polymerase from E.coli containing the sigma54 factor within the closed-promoter complex. Comparisons with earlier reconstructions of the core enzyme and the sigma54 holoenzyme reveal the behaviour of this major variant RNA polymerase in defined functional states. The binding of DNA leads to significant conformational changes in the enzyme's catalytic subunits, apparently a necessity for the initiation of enhancer-dependent promoter-specific transcription.
authors.affiliation: Department of Biological Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Pampa
authors.initials: P
authors.lastname: Ray
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Hall
authors.forename: Robert D
authors.initials: RD
authors.lastname: Finn
authors.forename: Shaoxia
authors.initials: S
authors.lastname: Chen
authors.forename: Ardan
authors.initials: A
authors.lastname: Patwardhan
authors.forename: Martin
authors.initials: M
authors.lastname: Buck
authors.forename: Marin
authors.initials: M
authors.lastname: van Heel
mesh_terms: D001665:Binding Sites; D020285:Cryoelectron Microscopy; D003460:Crystallization; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D004926:Escherichia coli / Q000201:enzymology*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011487:Protein Conformation; D051877:RNA Polymerase Sigma 54 / Q000737:chemistry* / Q000648:ultrastructure; D014158:Transcription, Genetic
chemical_list: D004269:DNA, Bacterial; D051877:RNA Polymerase Sigma 54