EMD-41664
Cryo-EM structure of S. cerevisiae Ctf18-RFC-PCNA-PolE-DNA complex
EMD-41664
Single-particle4.1 Å
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Map released: 04/09/2024
Last modified: 09/10/2024
Sample Organism:
Saccharomyces cerevisiae,
synthetic construct
Sample: Ctf18-RFC-PCNA-PolE-DNA complex
Fitted models: 8twa (Avg. Q-score: 0.349)
Deposition Authors: Yuan Z
,
Georgescu R
,
O'Donnell M,
Li H
Sample: Ctf18-RFC-PCNA-PolE-DNA complex
Fitted models: 8twa (Avg. Q-score: 0.349)
Deposition Authors: Yuan Z
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Mechanism of PCNA loading by Ctf18-RFC for leading-strand DNA synthesis.
Yuan Z
,
Georgescu R
,
Yao NY
,
Yurieva O
,
O'Donnell ME
,
Li H
(2024) Science , 385 , eadk5901 - eadk5901
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(2024) Science , 385 , eadk5901 - eadk5901
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.
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.