title: Beta subunit residues 186-433 and 436-445 are commonly used by Esigma54 and Esigma70 RNA polymerase for open promoter complex formation.
abstract: During transcription initiation by DNA-dependent RNA polymerase (RNAP) promoter DNA has to be melted locally to allow the synthesis of RNA transcript. Localized melting of promoter DNA is a target for genetic regulation and is poorly understood at the molecular level. The Escherichia coli RNAP holoenzyme is a six-subunit (alpha(2)betabeta'omegasigma; Esigma) protein complex. The sigma subunit is directly responsible for promoter recognition and contributes to localized DNA melting. Mutations in the beta subunit have profound effects on promoter melting by Esigma70. The sigma54 subunit is a representative of an unrelated class of the sigma subunits. Here, we determined whether mutations in the beta subunit that affect late stages of promoter complex formation by Esigma70 also influence promoter complex formation by the enhancer-dependent Esigma54. Analyses of in vitro defects in promoter complex formation and transcription initiation exhibited by mutant Esigma54 suggest that during promoter complex formation by Esigma54 and Esigma70 a common set of beta subunit sequences is used. Late stages of promoter complex formation and localized melting of promoter DNA by Esigma70 and Esigma54 thus proceed through a common pathway.
authors.affiliation: Department of Biological Sciences, Imperial College of Science, Technology and Medicine, Biomedical Sciences Building, Imperial College Road, London SW7 2AZ, UK.
authors.forename: Siva R
authors.initials: SR
authors.lastname: Wigneshweraraj
authors.forename: Sergei
authors.initials: S
authors.lastname: Nechaev
authors.forename: Konstantin
authors.initials: K
authors.lastname: Severinov
authors.forename: Martin
authors.initials: M
authors.lastname: Buck
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D018983:DNA Footprinting; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004278:DNA, Superhelical / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D020035:Holoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000201:enzymology*; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009691:Nucleic Acid Denaturation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation; D021122:Protein Subunits; D051877:RNA Polymerase Sigma 54; D017384:Sequence Deletion / Q000235:genetics; D012808:Sigma Factor / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013698:Templates, Genetic; D013816:Thermodynamics; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D015342:DNA Probes; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D020035:Holoenzymes; D046911:Macromolecular Substances; D021122:Protein Subunits; C098954:PspF protein, E coli; D012808:Sigma Factor; D015534:Trans-Activators; C497751:rpoN protein, E coli; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54