title: Escherichia coli RNA polymerase core and holoenzyme structures.
abstract: Multisubunit RNA polymerase is an essential enzyme for regulated gene expression. Here we report two Escherichia coli RNA polymerase structures: an 11.0 A structure of the core RNA polymerase and a 9.5 A structure of the sigma(70) holoenzyme. Both structures were obtained by cryo-electron microscopy and angular reconstitution. Core RNA polymerase exists in an open conformation. Extensive conformational changes occur between the core and the holoenzyme forms of the RNA polymerase, which are largely associated with movements in ss'. All common RNA polymerase subunits (alpha(2), ss, ss') could be localized in both structures, thus suggesting the position of sigma(70) in the holoenzyme.
authors: Departments of Biochemistry and Biology, Imperial College of Science, Technology and Medicine, London SW7 2AY, UK.
authors: R D
authors: RD
authors: Finn
authors: E V
authors: EV
authors: Orlova
authors: B
authors: B
authors: Gowen
authors: M
authors: M
authors: Buck
authors: M
authors: M
authors: van Heel
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000648:ultrastructure*; D019281:Dimerization; D004926:Escherichia coli / Q000201:enzymology*; D006358:Hot Temperature; D007091:Image Processing, Computer-Assisted; D008958:Models, Molecular; D011487:Protein Conformation; D021122:Protein Subunits; D012808:Sigma Factor / Q000737:chemistry* / Q000648:ultrastructure*; D013816:Thermodynamics; D013824:Thermus / Q000201:enzymology
chemical_list: D001426:Bacterial Proteins; D021122:Protein Subunits; D012808:Sigma Factor; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases