National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM087350
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM093142
米国
引用
ジャーナル: J Biol Chem / 年: 2018 タイトル: Cryo-EM structure of σ RNA polymerase and promoter DNA complex revealed a role of σ non-conserved region during the open complex formation. 著者: Anoop Narayanan / Frank S Vago / Kunpeng Li / M Zuhaib Qayyum / Dinesh Yernool / Wen Jiang / Katsuhiko S Murakami / 要旨: First step of gene expression is transcribing the genetic information stored in DNA to RNA by the transcription machinery including RNA polymerase (RNAP). In , a primary σ factor forms the RNAP ...First step of gene expression is transcribing the genetic information stored in DNA to RNA by the transcription machinery including RNA polymerase (RNAP). In , a primary σ factor forms the RNAP holoenzyme to express housekeeping genes. The σ contains a large insertion between the conserved regions 1.2 and 2.1, the σ non-conserved region (σ), but its function remains to be elucidated. In this study, we determined the cryo-EM structures of the RNAP σ holoenzyme and its complex with promoter DNA (open complex, RPo) at 4.2 and 5.75 Å resolutions, respectively, to reveal native conformations of RNAP and DNA. The RPo structure presented here found an interaction between the σ and promoter DNA just upstream of the -10 element, which was not observed in a previously determined RNAP transcription initiation complex (RPo plus short RNA) structure by X-ray crystallography because of restraint of crystal packing effects. Disruption of the σ and DNA interaction by the amino acid substitutions (R157A/R157E) influences the DNA opening around the transcription start site and therefore decreases the transcription activity of RNAP. We propose that the σ and DNA interaction is conserved in proteobacteria, and RNAP in other bacteria replaces its role with a transcription factor.