Fluorophore-Assisted Click Chemistry through Copper(I) Complexation.

Area of Science:

• Chemical Biology
• Bioconjugation Chemistry
• Fluorescence Imaging

Background:

• Copper-catalyzed alkyne-azide cycloaddition (CuAAC) is vital for selective biomolecule fluorescent labeling.
• Existing methods use bulky copper(I) ligands or chelating azides, potentially disrupting biomolecule function.
• There is a need for efficient CuAAC strategies with minimal perturbation to biomolecules.

Purpose of the Study:

• To develop and evaluate a compact fluorophore-based copper(I) chelating azide for accelerated CuAAC.
• To achieve efficient fluorescent labeling of biomolecules under dilute conditions.
• To investigate the potential for tuning reaction rates and photophysical properties using novel azide structures.

Main Methods:

• Synthesis of a novel, compact azide incorporating a fluorophore capable of chelating copper(I).
• Application of the developed azide in CuAAC reactions for peptide labeling.
• Utilizing the strategy for fluorescent labeling of live cells.

Main Results:

• The fluorophore-based azide successfully accelerated the CuAAC reaction.
• Efficient fluorescent labeling of a short peptide was achieved.
• Successful fluorescent labeling of live cells demonstrated the method's applicability in biological systems.
• The fluorophore retained its photophysical properties during copper(I) complexation.

Conclusions:

• A novel, compact fluorophore-copper(I) chelating azide strategy accelerates CuAAC reactions.
• This approach enables efficient fluorescent labeling of biomolecules and cells without increasing steric hindrance.
• The strategy holds promise for broader applications with other nitrogen-based fluorophores to optimize reaction kinetics and optical properties.