3aiz
From Proteopedia
Crystal structure of PCNA2-PCNA3 complex from Sulfolobus tokodaii (P21212)
Structural highlights
Function[PCNA2_SULTO] Sliding clamp subunit that acts as a moving platform for DNA processing. Responsible for tethering the catalytic subunit of DNA polymerase and other proteins to DNA during high-speed replication (By similarity). Both trimeric complexes inhibit DNA ligase and both 3'-5' and 5'-3' activity of Hel308 (Hjm) helicase, but stimulate Hjc, the Holliday junction cleavage enzyme.[HAMAP-Rule:MF_00317][1] [PCNA3_SULTO] Sliding clamp subunit that acts as a moving platform for DNA processing. Responsible for tethering the catalytic subunit of DNA polymerase and other proteins to DNA during high-speed replication (By similarity). Both trimeric complexes inhibit DNA ligase and both 3'-5' and 5'-3' activity of Hel308 (Hjm) helicase, but stimulate Hjc, the Holliday junction cleavage enzyme.[HAMAP-Rule:MF_00317][2] Publication Abstract from PubMedProliferating 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[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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