Biotechnology and Biological Sciences Research Council (BBSRC)
BB/N007816/1
英国
Medical Research Council (MRC, United Kingdom)
MR/P007503/1
英国
引用
ジャーナル: Sci Adv / 年: 2022 タイトル: Mechanisms of DNA opening revealed in AAA+ transcription complex structures. 著者: Fuzhou Ye / Forson Gao / Xiaojiao Liu / Martin Buck / Xiaodong Zhang / 要旨: Gene transcription is carried out by RNA polymerase (RNAP) and requires the conversion of the initial closed promoter complex, where DNA is double stranded, to a transcription-competent open promoter ...Gene transcription is carried out by RNA polymerase (RNAP) and requires the conversion of the initial closed promoter complex, where DNA is double stranded, to a transcription-competent open promoter complex, where DNA is opened up. In bacteria, RNAP relies on σ factors for its promoter specificities. Using a special form of sigma factor (σ), which forms a stable closed complex and requires its activator that belongs to the AAA+ ATPases (ATPases associated with diverse cellular activities), we obtained cryo-electron microscopy structures of transcription initiation complexes that reveal a previously unidentified process of DNA melting opening. The σ amino terminus threads through the locally opened up DNA and then becomes enclosed by the AAA+ hexameric ring in the activator-bound intermediate complex. Our structures suggest how ATP hydrolysis by the AAA+ activator could remove the σ inhibition while helping to open up DNA, using σ amino-terminal peptide as a pry bar.