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PDBsum entry 3k7a
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Transcription
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PDB id
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3k7a
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Contents |
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1408 a.a.
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1122 a.a.
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266 a.a.
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214 a.a.
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84 a.a.
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133 a.a.
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118 a.a.
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65 a.a.
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114 a.a.
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46 a.a.
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187 a.a.
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References listed in PDB file
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Key reference
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Title
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Structure of an RNA polymerase ii-Tfiib complex and the transcription initiation mechanism.
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Authors
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X.Liu,
D.A.Bushnell,
D.Wang,
G.Calero,
R.D.Kornberg.
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Ref.
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Science, 2010,
327,
206-209.
[DOI no: ]
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PubMed id
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Abstract
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Previous x-ray crystal structures have given insight into the mechanism of
transcription and the role of general transcription factors in the initiation of
the process. A structure of an RNA polymerase II-general transcription factor
TFIIB complex at 4.5 angstrom resolution revealed the amino-terminal region of
TFIIB, including a loop termed the "B finger," reaching into the active center
of the polymerase where it may interact with both DNA and RNA, but this
structure showed little of the carboxyl-terminal region. A new crystal structure
of the same complex at 3.8 angstrom resolution obtained under different solution
conditions is complementary with the previous one, revealing the
carboxyl-terminal region of TFIIB, located above the polymerase active center
cleft, but showing none of the B finger. In the new structure, the linker
between the amino- and carboxyl-terminal regions can also be seen, snaking down
from above the cleft toward the active center. The two structures, taken
together with others previously obtained, dispel long-standing mysteries of the
transcription initiation process.
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Figure 1.
Structure of pol II TFIIB complex. (A) "Top" view of pol II
in a surface representation, with previously identified domains
in the colors indicated, and with TFIIB in ribbon
representation. TFIIB zinc ribbon (TFIIB[N]), linker (TFIIB[L]),
first cyclin repeat (TFIIB[C]) are indicated. (B) Difference
(F[o]-F[c]) electron density map between pol II TFIIB and pol II
alone, contoured at 2.0[sigma], shown in green mesh, and Se-Met
anomalous peaks, contoured at 6-10[sigma], shown in blue mesh.
Science. Author manuscript; available in PMC 2010 January 28.
Published in final edited form as: Science. 2010 January 8;
327(5962): 206. Published online 2009 November 12. doi:
10.1126/science.1182015. Copyright notice and Disclaimer
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Figure 3.
Comparison of TFIIB and bacterial [sigma] factor structures.
(A) Superposition of TFIIB (red) and [sigma] factor (green)
structures. Conserved residues H455 and E458 of [sigma] factors
that bind to the -10 element and mark the start of transcription
bubble formation are highlighted as blue spheres. Corresponding
domains from TFIIB and [sigma] factor are labeled. (B) Same as
(A) rotated 45[deg] around the X-axis. The B-finger (TFIIB[F])
from the previous cocrystal structure is shown as a dashed black
line. Science. Author manuscript; available in PMC 2010 January
28. Published in final edited form as: Science. 2010 January 8;
327(5962): 206. Published online 2009 November 12. doi:
10.1126/science.1182015. Copyright notice and Disclaimer
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The above figures are
reprinted
from an Open Access publication published by the AAAs:
Science
(2010,
327,
206-209)
copyright 2010.
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