Azide–Alkyne Coupling: A Powerful Reaction for Bioconjugate Chemistry

Tying together biological molecules is a challenge for molecular biologists and chemists. The azide–alkyne 3+2 cycloaddition has recently been introduced as a highly chemoselective ligation reaction in chemical biology. It has found application in the preparation of carbohydrate arrays, in the modification of viruses such as the capsid of the cowpea mosaic virus (CPMV; see scheme), and in the activity-based protein profiling of whole cells.