SNAP/CLIP-Tags and Strain-Promoted Azide-Alkyne Cycloaddition (SPAAC)/Inverse Electron Demand Diels-Alder (IEDDA) for...

Area of Science:

• Biochemistry
• Chemical Biology
• Molecular Imaging

Background:

• Protein labeling is crucial for studying protein structure and dynamics in vivo.
• Synthetic dyes offer diverse photophysical properties for microscopy compared to fluorescent proteins.
• Bioorthogonal reactions combined with genetically encoded tags allow specific protein labeling in cells.

Purpose of the Study:

• To demonstrate the orthogonality of strain-promoted azide-alkyne cycloaddition (SPAAC) and inverse electron demand Diels-Alder (IEDDA) reactions for concurrent dual protein labeling.
• To validate a two-step labeling strategy using SNAP- and CLIP-tags for precise subcellular targeting.
• To expand the utility of protein tags beyond fluorophores for diverse molecular applications.

Main Methods:

• Genetically encoding SNAP- and CLIP-tags into proteins of interest.
• Installing azido and strained alkene functionalities at specific subcellular locations via enzymatic reactions.
• Performing simultaneous bioorthogonal reactions (SPAAC and IEDDA) with complementary fluorophores for dual labeling.

Main Results:

• Orthogonality of SPAAC and IEDDA reactions was confirmed for concurrent intracellular labeling.
• Simultaneous dual labeling of two distinct intracellular targets was achieved.
• The two-step orthogonal-bioorthogonal approach successfully decorated proteins with distinct functionalities.

Conclusions:

• The developed two-step orthogonal-bioorthogonal labeling strategy enables precise and simultaneous dual labeling of proteins in live and fixed cells.
• This method enhances the versatility of SNAP/CLIP-tags for advanced bioimaging and molecular studies.
• The approach has the potential to incorporate various functionalities, including spin labels, radioactive tracers, and catalysts, for expanded biological applications.