G1 PylT/RS(Y125A) RS/tRNA Pair Development Year 2020 ncAA(s) Incorporated N6-(1-Methylcycloprop-2-enecarboxamido)lysine (CpK) exoBCN-L-Lysine 2'-axialTCOK (TCO*) N6-((2-azidoethoxy)carbonyl)-L-lysine(AzeoK) propargylglycine