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PDBsum entry 2hii
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Contents |
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249 a.a.
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243 a.a.
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243 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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A flexible interface between DNA ligase and pcna supports conformational switching and efficient ligation of DNA.
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Authors
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J.M.Pascal,
O.V.Tsodikov,
G.L.Hura,
W.Song,
E.A.Cotner,
S.Classen,
A.E.Tomkinson,
J.A.Tainer,
T.Ellenberger.
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Ref.
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Mol Cell, 2006,
24,
279-291.
[DOI no: ]
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PubMed id
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Abstract
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DNA sliding clamps encircle DNA and provide binding sites for many
DNA-processing enzymes. However, it is largely unknown how sliding clamps like
proliferating cell nuclear antigen (PCNA) coordinate multistep DNA transactions.
We have determined structures of Sulfolobus solfataricus DNA ligase and
heterotrimeric PCNA separately by X-ray diffraction and in complex by
small-angle X-ray scattering (SAXS). Three distinct PCNA subunits assemble into
a protein ring resembling the homotrimeric PCNA of humans but with three unique
protein-binding sites. In the absence of nicked DNA, the Sulfolobus solfataricus
DNA ligase has an open, extended conformation. When complexed with
heterotrimeric PCNA, the DNA ligase binds to the PCNA3 subunit and ligase
retains an open, extended conformation. A closed, ring-shaped conformation of
ligase catalyzes a DNA end-joining reaction that is strongly stimulated by PCNA.
This open-to-closed switch in the conformation of DNA ligase is accommodated by
a malleable interface with PCNA that serves as an efficient platform for DNA
ligation.
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Figure 1.
Figure 1. Conformational States of DNA Ligase
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Figure 3.
Figure 3. ssLig Structure and Conformation in Solution
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The above figures are
reprinted
by permission from Cell Press:
Mol Cell
(2006,
24,
279-291)
copyright 2006.
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