11 Checkpoints controlled by PCNA, DNA and ATP direct the timing and order of events in the clamp loading mechanism

2015 ◽  
Vol 33 (sup1) ◽  
pp. 7-7
Author(s):  
Juan Liu ◽  
Manju M. Hingorani
Keyword(s):  
Clamp Loading

scholarly journals The molecular coupling between substrate recognition and ATP turnover in a AAA+ hexameric helicase loader

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Neha Puri ◽  
Amy J Fernandez ◽  
Valerie L O'Shea Murray ◽  
Sarah McMillan ◽  
James L Keck ◽  
...  
Keyword(s):  
Replication Fork ◽  
Substrate Recognition ◽  
Dna Unwinding ◽  
Replicative Helicase ◽  
E Coli ◽  
Helicase Loading ◽  
Dnab Helicase ◽  
Replication Restart ◽  
Clamp Loading ◽  
Aaa Atpases

In many bacteria and in eukaryotes, replication fork establishment requires the controlled loading of hexameric, ring-shaped helicases around DNA by AAA+ ATPases. How loading factors use ATP to control helicase deposition is poorly understood. Here, we dissect how specific ATPase elements of E. coli DnaC, an archetypal loader for the bacterial DnaB helicase, play distinct roles in helicase loading and the activation of DNA unwinding. We identify a new element, the arginine-coupler, which regulates the switch-like behavior of DnaC to prevent futile ATPase cycling and maintains loader responsiveness to replication restart systems. Our data help explain how the ATPase cycle of a AAA+-family helicase loader is channeled into productive action on its target; comparative studies indicate elements analogous to the Arg-coupler are present in related, switch-like AAA+ proteins that control replicative helicase loading in eukaryotes, as well as polymerase clamp loading and certain classes of DNA transposases.

scholarly journals Mechanisms of loading and release of the 9-1-1 checkpoint clamp

2021 ◽  
Author(s):  
Juan C Castaneda ◽  
Marina Schrecker ◽  
Dirk Remus ◽  
Richard K Hite
Keyword(s):  
Conformational Changes ◽  
Atp Hydrolysis ◽  
Clamp Loader ◽  
Opposite Orientation ◽  
Checkpoint Kinase ◽  
Sliding Clamp ◽  
Double Stranded Dna ◽  
Clamp Loading ◽  
Clamp Loaders ◽  
Open States

5' single-stranded/double-stranded DNA serve as loading sites for the checkpoint clamp, 9-1-1, which mediates activation of the apical checkpoint kinase, ATRMec1. However, the basis for 9-1-1's recruitment to 5' junctions is unclear. Here, we present structures of the yeast checkpoint clamp loader, Rad24-RFC, in complex with 9-1-1 and a 5' junction and in a post-ATP-hydrolysis state. Unexpectedly, 9-1-1 adopts both closed and planar open states in the presence of Rad24-RFC and DNA. Moreover, Rad24-RFC associates with the DNA junction in the opposite orientation of processivity clamp loaders with Rad24 exclusively coordinating the double-stranded region. ATP hydrolysis stimulates conformational changes in Rad24-RFC, leading to disengagement of DNA-loaded 9-1-1. Together, these structures explain 9-1-1's recruitment to 5' junctions and reveal new principles of sliding clamp loading.

scholarly journals Opening of a monomer-monomer interface of the trimeric bacteriophage T4-coded GP45 sliding clamp is required for clamp loading onto DNA

1999 ◽  
Vol 96 (22) ◽  
pp. 12448-12453 ◽  
Author(s):  
G. J. Latham ◽  
F. Dong ◽  
P. Pietroni ◽  
J. M. Dozono ◽  
D. J. Bacheller ◽  
...  
Keyword(s):  
Bacteriophage T4 ◽  
Sliding Clamp ◽  
Clamp Loading

scholarly journals Mechanism of ATP-Driven PCNA Clamp Loading by S. cerevisiae RFC

2009 ◽  
Vol 388 (3) ◽  
pp. 431-442 ◽  
Author(s):  
Siying Chen ◽  
Mikhail K. Levin ◽  
Miho Sakato ◽  
Yayan Zhou ◽  
Manju M. Hingorani
Keyword(s):  
Clamp Loading
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