8THC

Structure of the Saccharomyces cerevisiae clamp unloader Elg1-RFC bound to a cracked PCNA

Summary for 8THC

• Entry DOI: 10.2210/pdb8thc/pdb
• EMDB information: 41253
• Descriptor: ELG1 isoform 1, Replication factor C subunit 4, Replication factor C subunit 3, ... (9 entities in total)
• Functional Keywords: dna replication, dna sliding clamp, pcna clamp, clamp loader/unloader, elg1-rfc unloader, replication
• Biological source: Saccharomyces cerevisiae (baker's yeast); More
• Total number of polymer chains: 8
• Total formula weight: 335121.30

Authors

Zheng, F.,Yao, Y.N.,Georgescu, R.,O'Donnell, M.E.,Li, H. (deposition date: 2023-07-14, release date: 2024-05-22, Last modification date: 2024-05-29)

Primary citation

Zheng, F.,Yao, N.Y.,Georgescu, R.E.,Li, H.,O'Donnell, M.E.
Structure of the PCNA unloader Elg1-RFC.
Sci Adv, 10:eadl1739-eadl1739, 2024

PubMed Abstract: 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.

PubMed: 38427736
DOI: 10.1126/sciadv.adl1739

Experimental method

ELECTRON MICROSCOPY (3.67 Å)