6R9B

Cryo-EM structure of bacterial RNAP with a DNA mimic protein Ocr from T7 phage

Summary for 6R9B

• Entry DOI: 10.2210/pdb6r9b/pdb
• EMDB information: 4769
• Descriptor: DNA-directed RNA polymerase subunit alpha, DNA-directed RNA polymerase subunit beta, DNA-directed RNA polymerase subunit beta', ... (5 entities in total)
• Functional Keywords: transcription, rna polymerase, ocr, transcription inhibition, bacteriophage t7
• Biological source: Escherichia coli (strain K12); More
• Total number of polymer chains: 7
• Total formula weight: 416037.28

Authors

Ye, F.Z.,Zhang, X.D. (deposition date: 2019-04-03, release date: 2020-02-26, Last modification date: 2024-11-06)

Primary citation

Ye, F.,Kotta-Loizou, I.,Jovanovic, M.,Liu, X.,Dryden, D.T.,Buck, M.,Zhang, X.
Structural basis of transcription inhibition by the DNA mimic protein Ocr of bacteriophage T7.
Elife, 9:-, 2020

PubMed Abstract: Bacteriophage T7 infects and evades the host restriction/modification system. The Ocr protein of T7 was shown to exist as a dimer mimicking DNA and to bind to host restriction enzymes, thus preventing the degradation of the viral genome by the host. Here we report that Ocr can also inhibit host transcription by directly binding to bacterial RNA polymerase (RNAP) and competing with the recruitment of RNAP by sigma factors. Using cryo electron microscopy, we determined the structures of Ocr bound to RNAP. The structures show that an Ocr dimer binds to RNAP in the cleft, where key regions of sigma bind and where DNA resides during transcription synthesis, thus providing a structural basis for the transcription inhibition. Our results reveal the versatility of Ocr in interfering with host systems and suggest possible strategies that could be exploited in adopting DNA mimicry as a basis for forming novel antibiotics.

PubMed: 32039758
DOI: 10.7554/eLife.52125

Experimental method

ELECTRON MICROSCOPY (3.8 Å)