Genetically encoded cyclopropene directs rapid, photoclick-chemistry-mediated protein labeling in mammalian cells

We just click: Genetic incorporation of a cyclopropene amino acid CpK (see scheme) site-specifically into proteins in E. coli and mammalian cells was achieved using an orthogonal aminoacyl-tRNA synthetase/tRNA(CUA) pair (CpKRS/MbtRNA(CUA)). Cyclopropene exhibited fast reaction kinetics in the photoclick reaction and allowed rapid (ca. 2 min) labeling of proteins.