Structure of monoubiquitinated PCNA and implications for translesion synthesis and DNA polymerase exchange

Bret D Freudenthal; S Ramaswamy; Lokesh Gakhar; M Todd Washington

doi:10.1038/nsmb.1776

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Structure of monoubiquitinated PCNA and implications for translesion synthesis and DNA polymerase exchange

Journal article

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Structure of monoubiquitinated PCNA and implications for translesion synthesis and DNA polymerase exchange

Bret D Freudenthal, S Ramaswamy, Lokesh Gakhar and M Todd Washington

Nature Structural & Molecular Biology, Vol.17(4), pp.479-484

04/2010

DOI: 10.1038/nsmb.1776

PMCID: PMC2920209

PMID: 20305653

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Abstract

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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Title: Subtitle: Structure of monoubiquitinated PCNA and implications for translesion synthesis and DNA polymerase exchange
Creators: Bret D Freudenthal - Department of Biochemistry, University of Iowa College of Medicine
S Ramaswamy - Department of Biochemistry, University of Iowa College of Medicine
Lokesh Gakhar - Protein Crystallography Facility, University of Iowa College of Medicine
M Todd Washington - Department of Biochemistry, University of Iowa College of Medicine
Resource Type: Journal article
Publication Details: Nature Structural & Molecular Biology, Vol.17(4), pp.479-484
DOI: 10.1038/nsmb.1776
PMID: 20305653
PMCID: PMC2920209
NLM abbreviation: Nat Struct Mol Biol
ISSN: 1545-9993
eISSN: 1545-9985
Language: English
Date published: 04/2010
Academic Unit: Radiation Oncology; Biochemistry and Molecular Biology; Medicine Administration
Record Identifier: 9984024544602771

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