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Publication Abstract from PubMed

Proliferating cell nuclear antigen (PCNA) is a key protein that orchestrates the arrangement of DNA-processing proteins on DNA during DNA metabolism. In crenarchaea, PCNA forms a heterotrimer (PCNA123) consisting of PCNA1, PCNA2, and PCNA3, while in most eukaryotes and many archaea PCNAs form a homotrimer. Interestingly, unique oligomeric PCNAs from Sulfolobus tokodaii were reported in which PCNA2 and PCNA3 form a heterotrimer without PCNA1. In this paper, we describe the crystal structure of the stoPCNA2-stoPCNA3 complex. While most DNA sliding clamps form ring-shaped structures, our crystal structure showed an elliptic ring-like heterotetrameric complex, differing from a previous reports. Furthermore, we investigated the composition and the dimension of the stoPCNA2-stoPCNA3 complex in the solution using gel-filtration column chromatography and small-angle X-ray scattering analyses, respectively. These results indicate that stoPCNA2 and stoPCNA3 form the heterotetramer in solution. Based on our heterotetrameric structure, we propose a possible biological role for the heterotetrameric complex as a Holliday junction clamp.

A novel heterotetrameric structure of the crenarchaeal PCNA2-PCNA3 complex.,Kawai A, Hashimoto H, Higuchi S, Tsunoda M, Sato M, Nakamura KT, Miyamoto S J Struct Biol. 2011 Jun;174(3):443-50. Epub 2011 Feb 23. PMID:21352919^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.