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HaloTag Engineering for Enhanced Fluorogenicity and Kinetics with a Styrylpyridium Dye
Carla Miró-Vinyals1,2, Alina Stein1, Sandro Fischer1
1Chemistry Department, University of Basel, NCCR Molecular Systems Engineering, 4002, Basel, Switzerland.
Chembiochem : a European Journal of Chemical Biology
|October 5, 2021
Summary
Researchers engineered HaloTag (a self-labeling protein) to work with new, inexpensive dyes. This improved imaging in cells, offering a valuable tool for biological research and demonstrating protein engineering for alternative fluorophores.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- HaloTag is a widely used self-labeling protein for fluorescent reporters in living cells.
- Current HaloTag dyes are rhodamine-based, often expensive and difficult to synthesize.
Purpose of the Study:
- To engineer HaloTag for compatibility with a novel, accessible, and inexpensive fluorophore.
- To enhance the fluorogenicity and bioconjugation kinetics of HaloTag for improved cellular imaging.
Main Methods:
- Directed evolution was employed to improve HaloTag variants.
- Crystallographic characterization was used to understand structural changes.
Main Results:
- Engineered HaloTag variants showed significantly improved fluorogenicity (up to 4-fold) and bioconjugation rates (up to 42-fold).
- A top variant, HT-SP5, achieved a 113-fold fluorescence enhancement in mammalian cells.
- Structural analysis provided insights into the mechanisms of fluorescence enhancement.
Conclusions:
- The engineered HaloTag-dye system provides a cost-effective and efficient alternative for cellular imaging.
- This work validates the engineering of self-labeling proteins for novel fluorophore applications.
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