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Updated: Jan 13, 2026
09:16
In Vitro Directed Evolution of a Restriction Endonuclease with More Stringent Specificity
Published on: March 25, 2020
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Modular determinants of cleavage preference in GIY-YIG nucleases revealed by block-based DNA shuffling and directed
Kurt W Loedige1, Mairwyn A Hall1, Sabin Ghimirey1
1Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada.
Nucleic Acids Research
|January 7, 2026
Summary
Researchers engineered GIY-YIG homing endonucleases by swapping structural blocks, identifying a key region that controls DNA cleavage preference. This work enables engineering nucleases with novel target specificities.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- GIY-YIG homing endonucleases are mobile genetic elements with modular structures.
- Their sequence-tolerant DNA cleavage is crucial for target-site switching and adaptation.
Purpose of the Study:
- To investigate the modular determinants of GIY-YIG nuclease DNA cleavage preference.
- To understand how structural elements influence target recognition and specificity.
Main Methods:
- Constructed 128 chimeric nucleases by shuffling structural blocks between I-TevI and I-BmoI.
- Utilized directed evolution to identify key residues for altered cleavage preference.
- Analyzed changes in motif preference after structural modifications.
Main Results:
- Swapping the α-helix1 and adjacent loop altered nuclease motif preference.
- Directed evolution identified residues (R30, K33, E36, C39) that reprogrammed cleavage specificity.
- Engineered variants showed altered preference for TNNNG and GNNNG motifs.
Conclusions:
- A modular and structural basis for GIY-YIG nuclease cleavage preference was defined.
- Recombination of structural subunits can accelerate adaptation to new target sites.
- Findings support engineering GIY-YIG nucleases for expanded cleavage motif selectivity.
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