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PDBsum entry 2wnm
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References listed in PDB file
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Key reference
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Title
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T7 phage protein gp2 inhibits the escherichia coli RNA polymerase by antagonizing stable DNA strand separation near the transcription start site.
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Authors
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B.Cámara,
M.Liu,
J.Reynolds,
A.Shadrin,
B.Liu,
K.Kwok,
P.Simpson,
R.Weinzierl,
K.Severinov,
E.Cota,
S.Matthews,
S.R.Wigneshweraraj.
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Ref.
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Proc Natl Acad Sci U S A, 2010,
107,
2247-2252.
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PubMed id
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Abstract
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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 ( approximately 7 kDa) 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 surface-exposed 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
RNAP-promoter 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.
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