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Updated: Jun 22, 2026
06:24
Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad51
Published on: February 13, 2019
The Hin recombinase assembles a tetrameric protein swivel that exchanges DNA strands
Gautam Dhar1, Meghan M McLean, John K Heiss
1Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Nucleic Acids Research
|June 12, 2009
Summary
This study reveals how Hin serine recombinase undergoes large structural changes during DNA exchange. Site-directed crosslinking provides evidence for subunit rotation, a key mechanism in serine recombinase function.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Site-specific recombinases are crucial enzymes in DNA manipulation.
- Serine recombinases, unlike tyrosine recombinases, undergo significant conformational changes during DNA strand exchange.
Purpose of the Study:
- To investigate the conformational changes during synaptic complex formation and DNA exchange by the Hin serine recombinase.
- To provide experimental evidence for the subunit rotation mechanism in serine recombinases.
Main Methods:
- Site-directed crosslinking was employed to probe protein-protein interactions.
- Cysteine residues were introduced at specific positions within the D-helix and E-helix regions.
Main Results:
- Efficient crosslinking in the D-helix region confirmed interactions between synapsed subunits.
- Crosslinking data supported the proposed helical structure of the E-helix region.
- Experimental evidence strongly supports a subunit rotation mechanism mediating DNA exchange.
Conclusions:
- The study provides the first experimental evidence for subunit interactions in the D-helix region of Hin serine recombinase.
- The findings support a subunit rotation model for DNA exchange mediated by the E-helix region.
- This research elucidates key mechanistic steps in serine recombinase function.
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