Structures of RNA polymerase closed and intermediate complexes reveal mechanisms of DNA opening and transcription initiation

DOI: 10.1016/j.molcel.2017.05.010

Authors: Robert Glyde (Imperial College London) , Fuzhou Ye (Imperial College London) , Vidya Chandran Darbari (Imperial College London) , Nan Zhang (Imperial College London) , Martin Buck (Imperial College London) , Xiaodong Zhang (Imperial College London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Molecular Cell

State: Published (Approved)
Published: June 2017
Diamond Proposal Number(s): 13899 , 14769

Abstract: Gene transcription is carried out by RNA polymerases (RNAPs). For transcription to occur, the closed promoter complex (RPc), where DNA is double stranded, must isomerize into an open promoter complex (RPo), where the DNA is melted out into a transcription bubble and the single-stranded template DNA is delivered to the RNAP active site. Using a bacterial RNAP containing the alternative σ54 factor and cryoelectron microscopy, we determined structures of RPc and the activator-bound intermediate complex en route to RPo at 3.8 and 5.8 Å. Our structures show how RNAP-σ54 interacts with promoter DNA to initiate the DNA distortions required for transcription bubble formation, and how the activator interacts with RPc, leading to significant conformational changes in RNAP and σ54 that promote RPo formation. We propose that DNA melting is an active process initiated in RPc and that the RNAP conformations of intermediates are significantly different from that of RPc and RPo.

Journal Keywords: transcription initiation; DNA opening; transcription bubble; sigma factor; RNA polymerase; sigma54; AAA protein; transcription intermediate complex; transcription closed complex; DNA distortion

Subject Areas: Biology and Bio-materials

Diamond Offline Facilities: Electron Bio-Imaging Centre (eBIC)
Instruments: Krios I-Titan Krios I at Diamond

Added On: 07/06/2017 09:25

Documents:
1-s2.0-S1097276517303271-main.pdf

Discipline Tags:

Genetics Structural biology Life Sciences & Biotech

Technical Tags:

Microscopy Electron Microscopy (EM) Cryo Electron Microscopy (Cryo EM)