Related Experiment Videos
Triple-helical DNA pairing intermediates formed by recA protein
S W Umlauf1, M M Cox, R B Inman
1Department of Biochemistry, University of Wisconsin, Madison 53706.
The Journal of Biological Chemistry
|October 5, 1990
Summary
RecA protein forms three-stranded DNA joints during strand exchange. These joints, when cross-linked, reveal substructures suggesting a right-handed triple helix, aiding homologous DNA pairing.
Area of Science:
- Molecular Biology
- Structural Biology
- Genetics
Background:
- RecA protein is crucial for homologous recombination and DNA repair.
- It facilitates the alignment of DNA strands to form complex structures.
Purpose of the Study:
- To investigate the structural details of RecA-mediated DNA joints.
- To understand the role of RecA in DNA strand exchange and triple helix formation.
Main Methods:
- Cross-linking of RecA-DNA complexes using 4'-amino-4,5',8-trimethyl-psoralen.
- Structural analysis of the resulting DNA joints and substructures.
Main Results:
- RecA-mediated joints are nonuniform, composed of alternating substructures.
- At least one substructure is a right-handed triple helix, interspersed with non-contact regions.
- Joint formation is enhanced with linear DNA and unrestricted interwinding.
Conclusions:
- RecA protein facilitates the formation of a right-handed triple-helical DNA pairing intermediate during strand exchange.
- RecA filaments may not efficiently compensate for topological constraints during this process.