title: Mechanism of stimulation of ribosomal promoters by binding of the +1 and +2 nucleotides.
abstract: The rate of transcription of Escherichia coli ribosomal RNA promoters is central to adjusting the cellular growth rate to nutritional conditions. The +1 initiating nucleotide and ppGpp are regulatory effectors of these promoters. The data herein show that in vitro transcription is also regulated by the +2 nucleotide. Both the +1 and +2 nucleotides act by driving polymerase into an altered conformation rather than by increasing the lifetime of transcription complexes. The unique design of the ribosomal promoters may stabilize a distorted state of polymerase that is relieved by the binding of the two nucleotides required for transcription initiation.
authors.affiliation: Department of Chemistry and Biochemistry, and Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA 90095-1569, USA.
authors.forename: Chih M
authors.initials: CM
authors.lastname: Lew
authors.forename: Jay D
authors.initials: JD
authors.lastname: Gralla
mesh_terms: D001665:Binding Sites; D004247:DNA / Q000737:chemistry; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006493:Heparin / Q000494:pharmacology; D007700:Kinetics; D009711:Nucleotides / Q000737:chemistry*; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D012335:RNA, Ribosomal / Q000737:chemistry; D012270:Ribosomes / Q000235:genetics* / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D009711:Nucleotides; D012335:RNA, Ribosomal; D006493:Heparin; D004247:DNA; D012321:DNA-Directed RNA Polymerases