SNAPpa: A Photoactivatable SNAP-tag for the Spatiotemporal Control of Protein Labeling

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Imaging

Background:

• SNAP-tag is a widely used protein for cell imaging.
• Selective spatiotemporal control in cell imaging remains a challenge.

Purpose of the Study:

• To engineer a photoactivatable SNAP-tag for precise spatiotemporal cell imaging.
• To investigate the optimal placement of a photocaged amino acid for photoactivation.

Main Methods:

• Incorporation of *o*-nitrobenzyl-*O*-tyrosine (ONBY) into tyrosine positions of SNAP-tag.
• In-gel imaging analysis and fluorescence polarization measurements.
• Testing of the photoactivatable SNAP-tag (SNAPpa) in HEK293 cells for live-cell imaging.

Main Results:

• ONBY at position Y114 of SNAP-tag resulted in the most effective photoactivation.
• The engineered SNAPpa variant demonstrated light-induced fluorescence activation in live cells.
• SNAPpa enabled precise spatiotemporal control of fluorescence labeling in intracellular and extracellular imaging.

Conclusions:

• SNAPpa allows for efficient, light-induced activation of fluorescence labeling.
• SNAPpa is easily established and implemented with existing SNAP-tag substrates.
• This photoactivatable tag offers precise spatiotemporal control for advanced cell imaging applications.