6t8h
From Proteopedia
Cryo-EM structure of the DNA-bound PolD-PCNA processive complex from P. abyssi
Structural highlights
Function[PCNA_PYRAB] 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). Regulates activity of NucS endonuclease and prevents non-specific cleavage.[HAMAP-Rule:MF_00317][1] [DP2S_PYRAB] Possesses two activities: a DNA synthesis (polymerase) and an exonucleolytic activity that degrades single-stranded DNA in the 3' to 5' direction. Has a template-primer preference which is characteristic of a replicative DNA polymerase (By similarity). Publication Abstract from PubMedReplicative DNA polymerases (DNAPs) have evolved the ability to copy the genome with high processivity and fidelity. In Eukarya and Archaea, the processivity of replicative DNAPs is greatly enhanced by its binding to the proliferative cell nuclear antigen (PCNA) that encircles the DNA. We determined the cryo-EM structure of the DNA-bound PolD-PCNA complex from Pyrococcus abyssi at 3.77 A. Using an integrative structural biology approach - combining cryo-EM, X-ray crystallography, protein-protein interaction measurements, and activity assays - we describe the molecular basis for the interaction and cooperativity between a replicative DNAP and PCNA. PolD recruits PCNA via a complex mechanism, which requires two different PIP-boxes. We infer that the second PIP-box, which is shared with the eukaryotic Polalpha replicative DNAP, plays a dual role in binding either PCNA or primase, and could be a master switch between an initiation and a processive phase during replication. Structural basis for the increased processivity of D-family DNA polymerases in complex with PCNA.,Madru C, Henneke G, Raia P, Hugonneau-Beaufet I, Pehau-Arnaudet G, England P, Lindahl E, Delarue M, Carroni M, Sauguet L Nat Commun. 2020 Mar 27;11(1):1591. doi: 10.1038/s41467-020-15392-9. PMID:32221299[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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