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A Mechanism for RecA-Promoted Sequence Homology Recognition and Strand Exchange Between Single-Stranded DNA and
G Bertucat1, R Lavery, C Prévost
1a Laboratoire de Biochimie Théorique, CNRS UPR 9080 , Institut de Biologie Physico-Chimique , 13, rue Pierre et Marie Curie , 75005 , Paris , France.
Journal of Biomolecular Structure & Dynamics
|May 22, 2012
Summary
RecA protein facilitates homologous recombination by promoting DNA strand exchange. A new atomic-level model reveals unusual triple-helix intermediates during this process, involving DNA deformation and sequence recognition.
Area of Science:
- Molecular Biology
- Biophysics
- Structural Biology
Background:
- RecA protein is crucial for homologous recombination, mediating DNA sequence recognition and strand exchange.
- Understanding the RecA-mediated DNA interactions at an atomic level is key to elucidating recombination mechanisms.
Purpose of the Study:
- To propose a novel atomic-level model for RecA-mediated DNA recognition and strand exchange.
- To investigate the structural intermediates involved in the homologous recombination process.
Main Methods:
- Computational modeling and analysis of DNA properties under RecA-induced deformation.
- Exploration of unusual triple-helical DNA structures.
Main Results:
- A model involving a novel, stretched, and unwound triple helix where the single strand invades the minor groove in parallel orientation.
- Strand exchange is exothermic, forming an R-DNA triple helix with major groove interaction.
- Sequence homology recognition is partial during initial association and completed during strand exchange.
Conclusions:
- The proposed model provides atomic-level insights into RecA's function in homologous recombination.
- Unusual triple-helical structures are critical intermediates in RecA-mediated DNA strand exchange.
- The findings advance our understanding of DNA repair and genetic recombination processes.
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