Tetra-fluorinated aromatic azide for highly efficient bioconjugation in living cells.

Xuekang Cai,Yasi Gao,Zhen Xi,Xing Yang,Dan Wang,Long Yi

doi:10.1039/c8ra09303b

Abstract

We developed a fast strain-promoted azide–alkyne cycloaddition reaction (SPAAC) by tetra-fluorinated aromatic azide with a kinetic constant of 3.60 M−1 s−1, which is among the fastest SPAAC ligations reported so far. We successfully employed the reaction for covalent labelling of proteins with high efficiency and for bioimaging of mitochondria in living cells. The reaction could be a generally useful toolbox for chemical biology and biomaterials.

Highlights

We developed a fast strain-promoted azide–alkyne cycloaddition reaction (SPAAC) by tetra-fluorinated aromatic azide with a kinetic constant of 3.60 MÀ1 sÀ1, which is among the fastest SPAAC ligations reported so far
We reported o,o0di uorinated aromatic azide can accelerate both the reaction rate signi cantly on SPAAC and H2S-mediated reduction of the azide.12c we envision that multi- uorinated aromatic azide may have interesting properties for fast and convenient bifunctional conjugation. 4-Azido-2,3,5,6-tetra uorobenzoic acid (1) was selected for investigation
Product was con rmed by high resolution mass spectrum. This result implies that the 4-azido-2,3,5,6-tetra uorobenzoic acid derivatives can be used for this fast SPAAC reaction

Summary

Introduction

We developed a fast strain-promoted azide–alkyne cycloaddition reaction (SPAAC) by tetra-fluorinated aromatic azide with a kinetic constant of 3.60 MÀ1 sÀ1, which is among the fastest SPAAC ligations reported so far. We report the SPAAC kinetic properties of 1 and its applications for protein labelling in vitro and for bioimaging of subcellular organelles in living cells (Fig. 1). This result implies that the 4-azido-2,3,5,6-tetra uorobenzoic acid derivatives can be used for this fast SPAAC reaction. In order to quantify the kinetic rate, we designed a procedure based on uorescence resonance energy transfer (FRET) method to monitor this fast SPAAC reaction.

Results

Conclusion