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Design and optimization of effector-activated ribozyme ligases
1Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, A4800, 2500 Speedway, University of Texas at Austin, Austin, TX 78712, USA.
Nucleic Acids Research
|March 29, 2000
Summary
Researchers engineered ribozyme ligases into allosteric enzymes. These aptazymes respond to specific small organic molecules, demonstrating enhanced catalytic activity with effector molecules like ATP and theophylline.
Area of Science:
- Biochemistry
- Molecular Biology
- Synthetic Biology
Background:
- Ribozymes are RNA molecules with catalytic activity.
- Engineering ribozymes to respond to external stimuli is a key goal in synthetic biology.
- Previous work focused on hammerhead ribozymes and their aptazymes.
Purpose of the Study:
- To engineer a selected ribozyme ligase (L1) to function as an allosteric enzyme.
- To create aptazymes responsive to small organic effectors.
- To investigate the role of the joining region in aptazyme function and effector response.
Main Methods:
- Engineering a ribozyme ligase (L1) core structure.
- Appending aptamers (adenosine, theophylline, anti-flavin) to the ribozyme core.
- Rational sequence substitutions and randomization of the joining region.
- Negative and positive selection strategies for aptazyme optimization.
Main Results:
- Engineered aptazymes showed significant activity enhancement (800-1600-fold) with ATP and theophylline.
- Initial flavin-responsive aptazymes exhibited minimal activity.
- Selection yielded flavin-responsive aptazymes with up to 260-fold activation by FMN.
- Identified 'communication modules' in the joining region for aptamer-ribozyme linkage.
Conclusions:
- Ribozyme ligases can be readily engineered into allosteric enzymes.
- The joining region acts as a crucial communication module for aptazyme function.
- Techniques for engineering hammerhead aptazymes are generalizable to other ribozyme systems.