A charged residue at the subunit interface of PCNA promotes trimer formation by destabilizing alternate subunit interactions

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

doi:10.1107/S0907444909011329

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A charged residue at the subunit interface of PCNA promotes trimer formation by destabilizing alternate subunit interactions

Journal article

Open access

A charged residue at the subunit interface of PCNA promotes trimer formation by destabilizing alternate subunit interactions

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

Acta crystallographica. Section D, Biological crystallography, Vol.65(Pt 6), pp.560-566

06/2009

DOI: 10.1107/S0907444909011329

PMCID: PMC2685733

PMID: 19465770

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Abstract

Eukaryotic proliferating cell nuclear antigen (PCNA) is an essential replication accessory factor that interacts with a variety of proteins involved in DNA replication and repair. Each monomer of PCNA has an N-terminal domain A and a C-terminal domain B. In the structure of the wild-type PCNA protein, domain A of one monomer interacts with domain B of a neighboring monomer to form a ring-shaped trimer. Glu113 is a conserved residue at the subunit interface in domain A. Two distinct X-ray crystal structures have been determined of a mutant form of PCNA with a substitution at this position (E113G) that has previously been studied because of its effect on translesion synthesis. The first structure was the expected ring-shaped trimer. The second structure was an unanticipated nontrimeric form of the protein. In this nontrimeric form, domain A of one PCNA monomer interacts with domain A of a neighboring monomer, while domain B of this monomer interacts with domain B of a different neighboring monomer. The B-B interface is stabilized by an antiparallel beta-sheet and appears to be structurally similar to the A-B interface observed in the trimeric form of PCNA. The A-A interface, in contrast, is primarily stabilized by hydrophobic interactions. Because the E113G substitution is located on this hydrophobic surface, the A-A interface should be less favorable in the case of the wild-type protein. This suggests that the side chain of Glu113 promotes trimer formation by destabilizing these possible alternate subunit interactions.

Protein Binding - genetics

Models, Chemical

Glutamine - metabolism

Crystallography, X-Ray

Saccharomyces cerevisiae - metabolism

Proliferating Cell Nuclear Antigen - genetics

Cloning, Molecular

Protein Multimerization - genetics

Glutamine - chemistry

Protein Stability

Crystallization

Mutant Proteins - genetics

DNA Replication

Mutant Proteins - metabolism

Binding Sites - genetics

Saccharomyces cerevisiae Proteins - genetics

Proliferating Cell Nuclear Antigen - chemistry

DNA Repair

Mutant Proteins - chemistry

Glutamine - genetics

Saccharomyces cerevisiae Proteins - metabolism

Hydrophobic and Hydrophilic Interactions

Protein Conformation

Mutation

Proliferating Cell Nuclear Antigen - metabolism

Saccharomyces cerevisiae Proteins - chemistry

Details

Title: Subtitle: A charged residue at the subunit interface of PCNA promotes trimer formation by destabilizing alternate subunit interactions
Creators: Bret D Freudenthal - Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, USA
Lokesh Gakhar
S Ramaswamy
M Todd Washington
Resource Type: Journal article
Publication Details: Acta crystallographica. Section D, Biological crystallography, Vol.65(Pt 6), pp.560-566
Publisher: United States
DOI: 10.1107/S0907444909011329
PMID: 19465770
PMCID: PMC2685733
ISSN: 1399-0047
eISSN: 1399-0047
Grant note: R01 GM081433 / NIGMS NIH HHS R01GM081433 / NIGMS NIH HHS
Language: English
Date published: 06/2009
Academic Unit: Radiation Oncology; Biochemistry and Molecular Biology; Medicine Administration
Record Identifier: 9984024566502771

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