title: Effects of substitutions at position 180 in the Escherichia coli RNA polymerase σ 70 subunit.
abstract: In order to investigate the role of His180 residue, located in the non-conserved region of the σ 70 subunit of Escherichia coli RNA polymerase, two mutant variants of the protein with substitutions for either alanine or glutamic acid were constructed and purified using the IMPACT system. The ability of mutant σ 70 subunits to interact with core RNA polymerase was investigated using native gel-electrophoresis. The properties of the corresponding reconstituted holoenzymes, as provided by gel shift analysis of their complexes with single- and double-stranded promoter-like DNA and by in vitro transcription experiments, allowed one to deduce that His180 influences several steps of transcription initiation, including core binding, promoter DNA recognition and open complex formation.
authors: Chemical Faculty, Lomonosov Moscow State University, 119992 Moscow, Russia. koroleva@genebee.msu.su
authors: Olga N
authors: ON
authors: Koroleva
authors: Stephen J W
authors: SJ
authors: Busby
authors: Valeriy L
authors: VL
authors: Drutsa
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000235:genetics* / Q000378:metabolism*; D004586:Electrophoresis; D024202:Electrophoretic Mobility Shift Assay; D004926:Escherichia coli / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011196:Potassium Permanganate; D011401:Promoter Regions, Genetic / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism*
chemical_list: D009841:Oligonucleotides; D012808:Sigma Factor; D011196:Potassium Permanganate; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases