Related Experiment Video
Updated: May 8, 2026
10:36
Visualization of UV-induced Replication Intermediates in E. coli using Two-dimensional Agarose-gel Analysis
Published on: December 21, 2010
RecG and UvsW catalyse robust DNA rewinding critical for stalled DNA replication fork rescue
Maria Manosas1, Senthil K Perumal, Piero R Bianco
11] Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain [2] CIBER-BBN de Bioingenieria, Biomateriales y Nanomedicina, Instituto de Sanidad Carlos III, Madrid, Spain.
Nature Communications
|September 10, 2013
Summary
DNA repair helicases, like bacteriophage T4 UvsW and E. coli RecG, actively rewind DNA, performing work against significant forces. This rewinding capability is crucial for rescuing stalled DNA replication forks.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- DNA helicases are crucial for DNA repair and genetic recombination, with dual roles in unwinding and rewinding DNA.
- Characterizing the DNA rewinding activity of helicases biochemically is challenging due to its thermodynamically favorable nature.
Purpose of the Study:
- To biochemically characterize the DNA rewinding activity of DNA repair helicases.
- To investigate the mechanism by which helicases perform work during DNA rewinding.
- To understand the role of DNA rewinding in rescuing stalled DNA replication forks.
Main Methods:
- Utilized single-molecule assays to mechanically destabilize DNA molecules.
- Monitored DNA unwinding and rewinding by bacteriophage T4 UvsW and Escherichia coli RecG helicases in real time.
Main Results:
- Both T4 UvsW and RecG demonstrated robust DNA rewinding capabilities, actively working against forces up to 35 pN.
- The rewinding reaction was shown to generate work, enabling coupling to other DNA processes.
- These findings suggest a general mechanism for monomeric DNA rewinding enzymes.
Conclusions:
- DNA repair helicases possess active rewinding functions essential for DNA metabolism.
- The work-generating rewinding mechanism is vital for rescuing stalled replication forks.
- A unified mechanism for monomeric rewinding enzymes is supported by these results.
Related Concept Videos
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
01:02The DNA Replication Fork
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
01:02The DNA Replication Fork
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
02:31Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
02:31Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...