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PDBsum entry 3l0w
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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 monoubiquitinated pcna and implications for translesion synthesis and DNA polymerase exchange.
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Authors
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B.D.Freudenthal,
L.Gakhar,
S.Ramaswamy,
M.T.Washington.
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Ref.
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Nat Struct Biol, 2010,
17,
479-484.
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PubMed id
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Abstract
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DNA synthesis by classical polymerases can be blocked by many lesions. These
blocks are overcome by translesion synthesis, whereby the stalled classical,
replicative polymerase is replaced by a nonclassical polymerase. In eukaryotes
this polymerase exchange requires proliferating cell nuclear antigen (PCNA)
monoubiquitination. To better understand the polymerase exchange, we developed a
means of producing monoubiquitinated PCNA, by splitting the protein into two
self-assembling polypeptides. We determined the X-ray crystal structure of
monoubiquitinated PCNA and found that the ubiquitin moieties are located on the
back face of PCNA and interact with it through their canonical hydrophobic
surface. Moreover, the attachment of ubiquitin does not change PCNA's
conformation. We propose that PCNA ubiquitination facilitates nonclassical
polymerase recruitment to the back of PCNA by forming a new binding surface for
nonclassical polymerases, consistent with a 'tool belt' model of the polymerase
exchange.
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