8UII

Cryo-EM map of human clamp-clamp loader ATAD5-RFC-closed PCNA complex in intermediate state 1

Summary for 8UII

• Entry DOI: 10.2210/pdb8uii/pdb
• EMDB information: 42295
• Descriptor: ATPase family AAA domain-containing protein 5, Replication factor C subunit 2, Replication factor C subunit 5, ... (9 entities in total)
• Functional Keywords: aaa atpase, clamp unloader, motor protein
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 8
• Total formula weight: 455005.77

Authors

Wang, F.,He, Q.,Li, H. (deposition date: 2023-10-10, release date: 2024-05-29, Last modification date: 2025-05-14)

Primary citation

Wang, F.,He, Q.,Yao, N.Y.,O'Donnell, M.E.,Li, H.
The human ATAD5 has evolved unique structural elements to function exclusively as a PCNA unloader.
Nat.Struct.Mol.Biol., 31:1680-1691, 2024

PubMed Abstract: Humans have three different proliferating cell nuclear antigen (PCNA) clamp-loading complexes: RFC and CTF18-RFC load PCNA onto DNA, but ATAD5-RFC can only unload PCNA from DNA. The underlying structural basis of ATAD5-RFC unloading is unknown. We show here that ATAD5 has two unique locking loops that appear to tie the complex into a rigid structure, and together with a domain that plugs the DNA-binding chamber, prevent conformation changes required for DNA binding, likely explaining why ATAD5-RFC is exclusively a PCNA unloader. These features are conserved in the yeast PCNA unloader Elg1-RFC. We observe intermediates in which PCNA bound to ATAD5-RFC exists as a closed planar ring, a cracked spiral or a gapped spiral. Surprisingly, ATAD5-RFC can open a PCNA gap between PCNA protomers 2 and 3, different from the PCNA protomers 1 and 3 gap observed in all previously characterized clamp loaders.

PubMed: 38871854
DOI: 10.1038/s41594-024-01332-4

Experimental method

ELECTRON MICROSCOPY (3.04 Å)