Thiol-yne radical reaction mediated site-specific protein labeling via genetic incorporation of an alkynyl-L-lysine analogue.

Three alkyne-containing pyrrolysine derivatives were synthesized and genetically encoded into proteins by a mutant PylRS-tRNA pair with high efficiencies. With these alkyne handles, site-specific dual labeling of proteins can be achieved via a bioorthogonal thiol-yne ligation reaction.