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Updated: May 19, 2026
11:40
Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy
Published on: June 25, 2013
Complementary strand relocation may play vital roles in RecA-based homology recognition
Alexandra Peacock-Villada1, Darren Yang, Claudia Danilowicz
1Department of Physics, Harvard University, Cambridge, MA 02138, USA.
Nucleic Acids Research
|September 4, 2012
Summary
RecA-family proteins facilitate DNA repair by exchanging DNA strands. Applying force to the complementary strand hinders this process, revealing a key step in homology recognition during DNA recombination.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- RecA-family proteins are crucial for homologous recombination and DNA repair.
- They mediate DNA strand exchange through a multi-step process involving protein-DNA filament formation.
Purpose of the Study:
- To investigate the mechanical forces influencing RecA-mediated DNA strand exchange.
- To elucidate the structural intermediates and homology recognition mechanisms of RecA proteins.
Main Methods:
- Utilized single-molecule force spectroscopy to apply mechanical tension to DNA strands.
- Analyzed DNA extension rates and binding dynamics of RecA-family proteins.
Main Results:
- Force applied to the complementary strand significantly impedes strand exchange, while force on the outgoing strand has minimal effect.
- Identified an intermediate structural state required for RecA binding and strand exchange.
- Demonstrated that DNA strand relocation within the RecA filament limits strand exchange rates.
Conclusions:
- Homology recognition is regulated by transitions to and from a RecA-intermediate structure.
- Differential DNA extension within the intermediate structure drives homologous strand exchange and penalizes non-homologous interactions.
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