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The isomeric preference of Holliday junctions influences resolution bias by lambda integrase
The EMBO Journal
|June 1, 1997
Summary
Lambda site-specific recombination involves sequential strand exchanges. Lambda integrase resolves Holliday junctions stereochemically, indicating helix restacking during recombination.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- Site-specific recombination is crucial for genetic processes.
- Lambda site-specific recombination utilizes a Holliday junction intermediate.
- Understanding Holliday junction resolution is key to recombination mechanisms.
Purpose of the Study:
- To investigate the stereochemical distinctness of Holliday junction resolution.
- To determine the influence of DNA structure on lambda integrase resolution preference.
- To elucidate the mechanism of helix restacking in recombination.
Main Methods:
- Utilized synthetic Holliday junctions with constrained branch points.
- Analyzed resolution bias of lambda integrase on various junction structures.
- Correlated purine distribution with junction stacking preferences.
Main Results:
- Holliday junction resolution by lambda integrase is symmetrical yet stereochemically distinct.
- Lambda integrase preferentially resolves crossed strands in the protein-free junction.
- Junction stacking preferences predict resolution bias, supporting helix restacking.
Conclusions:
- Lambda integrase exhibits stereochemical sensitivity in Holliday junction resolution.
- DNA sequence and structure dictate resolution pathways.
- Helix restacking between strand exchanges is a critical step in lambda recombination.
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