scholarly journals Structural basis of transcription inhibition by the DNA mimic protein Ocr of bacteriophage T7

2019 ◽  
Author(s):  
Fuzhou Ye ◽  
Ioly Kotta-Loizou ◽  
Milija Jovanovic ◽  
Xiaojiao Liu ◽  
David T. F. Dryden ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Protein A ◽  
Restriction Enzymes ◽  
Sigma Factors ◽  
Structural Basis ◽  
Bacteriophage T7 ◽  
Transcription Inhibition ◽  
Host Restriction ◽  
Dna Mimicry ◽  
Host Defence System

AbstractBacteriophage T7 infects Escherichia coli and evades the host defence 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.Impact statementDNA mimicry Ocr protein, a well-studied T7 phage protein that inhibits host restriction enzymes, can also inhibit host transcription through competing with sigma factors in binding to RNA polymerase.

scholarly journals Structural basis of transcription inhibition by the DNA mimic protein Ocr of bacteriophage T7

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Fuzhou Ye ◽  
Ioly Kotta-Loizou ◽  
Milija Jovanovic ◽  
Xiaojiao Liu ◽  
David TF Dryden ◽  
...  
Keyword(s):  
Restriction Enzymes ◽  
Structural Basis ◽  
Bacteriophage T7 ◽  
Transcription Inhibition ◽  
Modification System ◽  
Host Restriction ◽  
Restriction Modification System ◽  
Cryo Electron Microscopy ◽  
Bacterial Rna ◽  
Restriction Modification

Bacteriophage T7 infects Escherichia coli 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.

scholarly journals Mycobacterium tuberculosis RNA Polymerase-binding Protein A (RbpA) and Its Interactions with Sigma Factors

2013 ◽  
Vol 288 (20) ◽  
pp. 14438-14450 ◽  
Author(s):  
Alessio Bortoluzzi ◽  
Frederick W. Muskett ◽  
Lorna C. Waters ◽  
Philip W. Addis ◽  
Barbara Rieck ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Rna Polymerase ◽  
Solution Structure ◽  
Binding Protein ◽  
Protein A ◽  
Hydrophobic Surface ◽  
Sigma Factors ◽  
Growth And Survival ◽  
Polymerase Binding ◽  
Sigma Subunit

RNA polymerase-binding protein A (RbpA), encoded by Rv2050, is specific to the actinomycetes, where it is highly conserved. In the pathogen Mycobacterium tuberculosis, RbpA is essential for growth and survival. RbpA binds to the β subunit of the RNA polymerase where it activates transcription by unknown mechanisms, and it may also influence the response of M. tuberculosis to the current frontline anti-tuberculosis drug rifampicin. Here we report the solution structure of RbpA and identify the principle sigma factor σA and the stress-induced σB as interaction partners. The protein has a central ordered domain with a conserved hydrophobic surface that may be a potential protein interaction site. The N and C termini are highly dynamic and are involved in the interaction with the sigma factors. RbpA forms a tight complex with the N-terminal domain of σB via its N- and C-terminal regions. The interaction with sigma factors may explain how RbpA stabilizes sigma subunit binding to the core RNA polymerase and thereby promotes initiation complex formation. RbpA could therefore influence the competition between principal and alternative sigma factors and hence the transcription profile of the cell.

scholarly journals Author response: Structural basis of transcription inhibition by the DNA mimic protein Ocr of bacteriophage T7

2020 ◽  
Author(s):  
Fuzhou Ye ◽  
Ioly Kotta-Loizou ◽  
Milija Jovanovic ◽  
Xiaojiao Liu ◽  
David TF Dryden ◽  
...  
Keyword(s):  
Author Response ◽  
Structural Basis ◽  
Bacteriophage T7 ◽  
Transcription Inhibition

scholarly journals Structural basis of Mycobacterium tuberculosis transcription and transcription inhibition

2017 ◽  
Author(s):  
Wei Lin ◽  
Soma Mandal ◽  
David Degen ◽  
Yu Liu ◽  
Yon W. Ebright ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Rna Polymerase ◽  
Crystal Structures ◽  
Binding Sites ◽  
Structural Basis ◽  
Cross Resistance ◽  
Antituberculosis Drug ◽  
Transcription Inhibition ◽  
First Line ◽  
Related Compounds

One Sentence SummaryStructures of Mycobacterium tuberculosis RNA polymerase reveal taxon-specific properties and binding sites of known and new antituberculosis agentsAbstractMycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, which kills 1.8 million annually. Mtb RNA polymerase (RNAP) is the target of the first-line antituberculosis drug rifampin (Rif). We report crystal structures of Mtb RNAP, alone and in complex with Rif. The results identify an Mtb-specific structural module of Mtb RNAP and establish that Rif functions by a steric-occlusion mechanism that prevents extension of RNA. We also report novel non-Rif-related compounds–Nα-aroyl-N-aryl-phenylalaninamides (AAPs)–that potently and selectively inhibit Mtb RNAP and Mtb growth, and we report crystal structures of Mtb RNAP in complex with AAPs. AAPs bind to a different site on Mtb RNAP than Rif, exhibit no cross-resistance with Rif, function additively when co-administered with Rif, and suppress resistance emergence when co-administered with Rif.

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