National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM131754
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM115809
米国
Howard Hughes Medical Institute (HHMI)
M.E.O.
米国
引用
ジャーナル: Science / 年: 2024 タイトル: Mechanism of PCNA loading by Ctf18-RFC for leading-strand DNA synthesis. 著者: Zuanning Yuan / Roxana Georgescu / Nina Y Yao / Olga Yurieva / Michael E O'Donnell / Huilin Li / 要旨: 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 ...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.