Strand Specificity in the Interactions ofEscherichia coliPrimary Replicative Helicase DnaB Protein with a Replication Fork†

Biochemistry ◽  
1997 ◽  
Vol 36 (33) ◽  
pp. 10320-10326 ◽  
Author(s):  
Maria J. Jezewska ◽  
Surendran Rajendran ◽  
Wlodzimierz Bujalowski
Keyword(s):  
Replication Fork ◽  
Replicative Helicase ◽  
Helicase Dnab

Complex ofEscherichia coliPrimary Replicative Helicase DnaB Protein with a Replication Fork:  Recognition and Structure†

Biochemistry ◽  
1998 ◽  
Vol 37 (9) ◽  
pp. 3116-3136 ◽  
Author(s):  
Maria J. Jezewska ◽  
Surendran Rajendran ◽  
Wlodzimierz Bujalowski
Keyword(s):  
Replication Fork ◽  
Replicative Helicase ◽  
Helicase Dnab

scholarly journals Replication fork stalling elicits chromatin compaction for the stability of stalling replication forks

2019 ◽  
Vol 116 (29) ◽  
pp. 14563-14572 ◽  
Author(s):  
Gang Feng ◽  
Yue Yuan ◽  
Zeyang Li ◽  
Lu Wang ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Replication Fork ◽  
Cellular Mechanism ◽  
Eukaryotic Cells ◽  
Replication Forks ◽  
Physical Separation ◽  
Replicative Helicase ◽  
Chromatin Compaction ◽  
Acetylation Site ◽  
Fork Stalling ◽  
The Stability

DNA replication forks in eukaryotic cells stall at a variety of replication barriers. Stalling forks require strict cellular regulations to prevent fork collapse. However, the mechanism underlying these cellular regulations is poorly understood. In this study, a cellular mechanism was uncovered that regulates chromatin structures to stabilize stalling forks. When replication forks stall, H2BK33, a newly identified acetylation site, is deacetylated and H3K9 trimethylated in the nucleosomes surrounding stalling forks, which results in chromatin compaction around forks. Acetylation-mimic H2BK33Q and its deacetylase clr6-1 mutations compromise this fork stalling-induced chromatin compaction, cause physical separation of replicative helicase and DNA polymerases, and significantly increase the frequency of stalling fork collapse. Furthermore, this fork stalling-induced H2BK33 deacetylation is independent of checkpoint. In summary, these results suggest that eukaryotic cells have developed a cellular mechanism that stabilizes stalling forks by targeting nucleosomes and inducing chromatin compaction around stalling forks. This mechanism is named the “Chromsfork” control: Chromatin Compaction Stabilizes Stalling Replication Forks.

scholarly journals Unwinding 20 Years of the Archaeal Minichromosome Maintenance Helicase

2020 ◽  
Vol 202 (6) ◽  
Author(s):  
Lori M. Kelman ◽  
William B. O’Dell ◽  
Zvi Kelman
Keyword(s):  
Dna Replication ◽  
Replication Fork ◽  
Duplex Dna ◽  
Chromosomal Dna ◽  
Minichromosome Maintenance ◽  
Replicative Helicase ◽  
Dna Helicases ◽  
First Report ◽  
20Th Anniversary

ABSTRACT Replicative DNA helicases are essential cellular enzymes that unwind duplex DNA in front of the replication fork during chromosomal DNA replication. Replicative helicases were discovered, beginning in the 1970s, in bacteria, bacteriophages, viruses, and eukarya, and, in the mid-1990s, in archaea. This year marks the 20th anniversary of the first report on the archaeal replicative helicase, the minichromosome maintenance (MCM) protein. This minireview summarizes 2 decades of work on the archaeal MCM.

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 Mechanism of RPA-Facilitated Processive DNA Unwinding by the Eukaryotic CMG Helicase

2019 ◽  
Author(s):  
Hazal B. Kose ◽  
Sherry Xie ◽  
George Cameron ◽  
Melania S. Strycharska ◽  
Hasan Yardimci
Keyword(s):  
Single Molecule ◽  
Replication Fork ◽  
Double Helix ◽  
Dna Unwinding ◽  
Helicase Activity ◽  
Replicative Helicase ◽  
Double Stranded Dna ◽  
Order Of Magnitude ◽  
Dna Strand ◽  
Dna Double Helix

AbstractThe DNA double helix is unwound by the Cdc45/Mcm2-7/GINS (CMG) complex at the eukaryotic replication fork. While isolated CMG unwinds duplex DNA very slowly, its fork unwinding rate is stimulated by an order of magnitude by single-stranded DNA binding protein, RPA. However, the molecular mechanism by which RPA enhances CMG helicase activity remained elusive. Here, we demonstrate that engagement of CMG with parental double-stranded DNA (dsDNA) at the replication fork impairs its helicase activity, explaining the slow DNA unwinding by isolated CMG. Using single-molecule and ensemble biochemistry, we show that binding of RPA to the excluded DNA strand prevents duplex engagement by the helicase and speeds up CMG-mediated DNA unwinding. When stalled due to dsDNA interaction, DNA rezipping-induced helicase backtracking re-establishes productive helicase-fork engagement underscoring the significance of plasticity in helicase action. Together, our results elucidate the dynamics of CMG at the replication fork and reveal how other replisome components can mediate proper DNA engagement by the replicative helicase to achieve efficient fork progression.

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