Mechanism of PCNA loading by Ctf18-RFC for leading-strand DNA synthesis.
Science
; 385(6708): eadk5901, 2024 Aug 02.
Article
in En
| MEDLINE
| ID: mdl-39088616
ABSTRACT
The proliferating cell nuclear antigen (PCNA) clamp encircles DNA to hold DNA polymerases (Pols) to DNA for processivity. The Ctf18-RFC PCNA loader, a replication factor C (RFC) variant, is specific to the leading-strand Pol (Polε). We reveal here the underlying mechanism of Ctf18-RFC specificity to Polε using cryo-electron microscopy and biochemical studies. We found that both Ctf18-RFC and Polε contain specific structural features that direct PCNA loading onto DNA. Unlike other clamp loaders, Ctf18-RFC has a disordered ATPase associated with a diverse cellular activities (AAA+) motor that requires Polε to bind and stabilize it for efficient PCNA loading. In addition, Ctf18-RFC can pry prebound Polε off of DNA, then load PCNA onto DNA and transfer the PCNA-DNA back to Polε. These elements in both Ctf18-RFC and Polε provide specificity in loading PCNA onto DNA for Polε.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Proliferating Cell Nuclear Antigen
/
DNA Replication
/
Replication Protein C
Limits:
Humans
Language:
En
Journal:
Science
Year:
2024
Document type:
Article
Affiliation country:
United States