Related Experiment Video
Updated: Jun 3, 2026
08:24
Visualization of Replisome Encounters with an Antigen Tagged Blocking Lesion
Published on: July 27, 2021
Interfacial instability and DNA fork reversal by repair proteins
1Institute of Physics, Bhubaneswar 751005, India. somen@iopb.res.in
Summary
DNA repair protein RecG facilitates stalled replication fork movement. Aromatic interactions at the Y-fork may soften the DNA interface, enabling fork propagation and potentially stop-and-go motion.
Area of Science:
- Molecular Biology
- Biophysics
Background:
- DNA replication forks can stall, requiring repair proteins to maintain genome stability.
- RecG is a protein known to interact with stalled replication forks.
Purpose of the Study:
- To propose a model for how RecG influences stalled replication fork movement.
- To investigate the role of DNA interface softening in fork propagation.
Main Methods:
- Theoretical modeling of DNA fork dynamics.
- Analysis of protein-DNA interactions based on crystal structure predictions.
Main Results:
- RecG promotes movement from zipped to unzipped DNA states.
- A softened DNA interface at the Y-fork allows fork propagation.
- Aromatic interactions between RecG and nascent base pairs can cause interface softening.
- Numerical analysis suggests a stop-and-go motion is possible.
Conclusions:
- RecG's action involves softening the DNA interface at stalled replication forks.
- This softening mechanism explains fork propagation directionality.
- The model provides insights into DNA repair dynamics and potential replication restart mechanisms.
More Related Videos
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...
02:04Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...