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Structures of bacterial RNA polymerase complexes reveal the mechanism of DNA loading and transcription initiation

DOI: 10.1016/j.molcel.2018.05.021 DOI Help

Authors: Robert Glyde (Imperial College London) , Fuzhou Ye (Imperial College London) , Milija Jovanovic (Imperial College London) , Ioly Kotta-loizou (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 , VOL 70 , PAGES 1111 - 1120.e3

State: Published (Approved)
Published: June 2018
Diamond Proposal Number(s): 14769

Open Access Open Access

Abstract: Gene transcription is carried out by multi-subunit RNA polymerases (RNAPs). Transcription initiation is a dynamic multi-step process that involves the opening of the double-stranded DNA to form a transcription bubble and delivery of the template strand deep into the RNAP for RNA synthesis. Applying cryoelectron microscopy to a unique transcription system using σ54 (σN), the major bacterial variant sigma factor, we capture a new intermediate state at 4.1 Å where promoter DNA is caught at the entrance of the RNAP cleft. Combining with new structures of the open promoter complex and an initial de novo transcribing complex at 3.4 and 3.7 Å, respectively, our studies reveal the dynamics of DNA loading and mechanism of transcription bubble stabilization that involves coordinated, large-scale conformational changes of the universally conserved features within RNAP and DNA. In addition, our studies reveal a novel mechanism of strand separation by σ54.

Journal Keywords: transcription initiation; DNA opening; transcription bubble; RNA polymerase; sigma; de novo RNA synthesis; protein-DNA interactions; promoter DNA; transcription activation; bacterial enhancer-binding proteins

Subject Areas: Biology and Bio-materials

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