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Site-specific Bacterial Chromosome Engineering: ΦC31 Integrase Mediated Cassette Exchange (IMCE)
Published on: March 16, 2012
Selection of bacteriophage lambda integrases with altered recombination specificity by in vitro compartmentalization
Yvonne Tay1, Candice Ho, Peter Droge
1p53 Laboratory, 8A Biomedical Grove, #06-06, Immunos, Singapore 138648.
Nucleic Acids Research
|December 8, 2009
Summary
Novel bacteriophage lambda integrase variants were developed using in vitro compartmentalization (IVC). These engineered integrases show enhanced DNA recombination activity, offering new tools for biotechnology.
Area of Science:
- Molecular Biology
- Biotechnology
- Enzyme Engineering
Background:
- Bacteriophage lambda integrase is a key enzyme for DNA recombination.
- Engineering integrase for enhanced activity on non-cognate DNA is crucial for biotechnological applications.
- In vitro compartmentalization (IVC) offers a powerful platform for enzyme evolution.
Purpose of the Study:
- To evolve novel bacteriophage lambda integrase variants with improved recombination activity on a non-cognate DNA target.
- To investigate the molecular basis for altered specificity and activity in engineered integrase variants.
- To establish a robust in vitro platform for developing new integrase tools.
Main Methods:
- Selection of bacteriophage lambda integrase variants using in vitro compartmentalization (IVC).
- Assay of recombination activity on cognate and non-cognate DNA substrates.
- Analysis of mutations in selected integrase variants.
- Validation of in vitro specificity in intracellular recombination assays.
Main Results:
- Isolated lambda integrase variants with up to 9-fold increased recombination activity on a non-cognate DNA sequence.
- Identified a variant that recombines the non-cognate substrate more efficiently than the parental enzyme recombines the wild-type substrate.
- Demonstrated that the enhanced in vitro specificity translates to intracellular recombination in HEK293 cells.
- Discovered that key mutations are located in the N-terminal domain, not the core-binding domain, suggesting a novel role in allosteric modulation of specificity.
Conclusions:
- IVC is an effective method for evolving bacteriophage lambda integrase with enhanced and altered DNA recombination specificity.
- The N-terminal domain of lambda integrase plays a critical, previously unrecognized role in directing enzyme specificity.
- The developed platform enables the creation of novel integrase reagents for DNA manipulation and biotechnology.
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