title: Abortive cycling and the release of polymerase for elongation at the sigma 54-dependent glnAp2 promoter.
abstract: Transcription initiation at the sigma 54-dependent glnAp2 promoter was studied to follow the state of polymerase as RNA synthesis begins. Sigma 54 polymerase begins transcription in abortive cycling mode, i.e. after the first bond is made, approximately 75% of the time the short RNA is aborted and synthesis must be restarted. Polymerase is capable of abortive initiation until it reaches a position beyond +3 and before +7, at which stage polymerase is released from its promoter contacts and an elongation complex is formed. INitial elongation is accompanied by two transcription bubbles, one moving with the polymerase and the other remaining at the transcription start site. The sigma 54-associated polymerase shows an earlier and more efficient transition out of abortive initiation mode than prior studies of sigma 70-associated polymerase.
authors.affiliation: Department of Chemistry and Biochemistry, UCLA 90095, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Tintut
authors.forename: J T
authors.initials: JT
authors.lastname: Wang
authors.forename: J D
authors.initials: JD
authors.lastname: Gralla
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000096:biosynthesis / Q000378:metabolism*; D003850:Deoxyribonuclease I; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D005974:Glutamate-Ammonia Ligase / Q000096:biosynthesis / Q000235:genetics*; D007700:Kinetics; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D051877:RNA Polymerase Sigma 54; D012329:RNA, Bacterial / Q000096:biosynthesis / Q000737:chemistry; D012265:Ribonucleotides / Q000378:metabolism; D012808:Sigma Factor / Q000096:biosynthesis / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D012329:RNA, Bacterial; D012265:Ribonucleotides; D012808:Sigma Factor; C497751:rpoN protein, E coli; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54; D003850:Deoxyribonuclease I; C081173:glutamine synthetase I; D005974:Glutamate-Ammonia Ligase