T7 phage protein Gp2 inhibits the Escherichia coli RNA polymerase by antagonizing stable DNA strand separation near the transcription start site

Beatriz Cámara, Minhao Liu, Jonathan Reynolds, Andrey Shadrin, Bing Liu, King Kwok, Peter Simpson, Robert Weinzierl, Konstantin Severinov, Ernesto Cota, Steve Matthews, Siva R. Wigneshweraraj

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)

Abstract

Infection of Escherichia coli by the T7 phage leads to rapid and selective inhibition of the host RNA polymerase (RNAP) - a multi-subunit enzyme responsible for gene transcription - by a small (∼7kDa) phage-encoded protein called Gp2. Gp2 is also a potent inhibitor of E. coli RNAP in vitro. Here we describe the first atomic resolution structure of Gp2, which reveals a distinct run of surfaceexposed negatively charged amino acid residues on one side of the molecule. Our comprehensive mutagenesis data reveal that two conserved arginine residues located on the opposite side of Gp2 are important for binding to and inhibition of RNAP. Based on a structural model of the Gp2-RNAP complex, we propose that inhibition of transcription by Gp2 involves prevention of RNAPpromoter DNA interactions required for stable DNA strand separation and maintenance of the "transcription bubble" near the transcription start site, an obligatory step in the formation of a transcriptionally competent promoter complex.

Original languageEnglish
Pages (from-to)2247-2252
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume107
Issue number5
DOIs
Publication statusPublished - 2 Feb 2010
Externally publishedYes

Keywords

  • Gene protein 2
  • Inhibitor
  • Promoter melting

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