8thb

Publication Abstract from PubMed

During DNA replication, the proliferating cell nuclear antigen (PCNA) clamps are loaded onto primed sites for each Okazaki fragment synthesis by the AAA(+) heteropentamer replication factor C (RFC). PCNA encircling duplex DNA is quite stable and is removed from DNA by the dedicated clamp unloader Elg1-RFC. Here, we show the cryo-EM structure of Elg1-RFC in various states with PCNA. The structures reveal essential features of Elg1-RFC that explain how it is dedicated to PCNA unloading. Specifically, Elg1 contains two external loops that block opening of the Elg1-RFC complex for DNA binding, and an "Elg1 plug" domain that fills the central DNA binding chamber, thereby reinforcing the exclusive PCNA unloading activity of Elg1-RFC. Elg1-RFC was capable of unloading PCNA using non-hydrolyzable AMP-PNP. Both RFC and Elg1-RFC could remove PCNA from covalently closed circular DNA, indicating that PCNA unloading occurs by a mechanism that is distinct from PCNA loading. Implications for the PCNA unloading mechanism are discussed.

Structure of the PCNA unloader Elg1-RFC.,Zheng F, Yao NY, Georgescu RE, Li H, O'Donnell ME Sci Adv. 2024 Mar;10(9):eadl1739. doi: 10.1126/sciadv.adl1739. Epub 2024 Mar 1. PMID:38427736^[1]

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