Figure 1.

Strategy for selective covalent modification of phosphorylated Tyr (Tyr^P, Y^P) within a peptide substrate. In vitro selection identifies deoxyribozymes that function with a Tyr^P-containing hexapeptide substrate, catalyzing attachment of 5′-triphosphorylated RNA to the phosphorylated amino acid residue. The hexapeptide substrate is attached to an oligonucleotide anchor via a tether (see text for composition). The product has a pyrophosphate linkage between Tyr and RNA. Further information about the selection procedure, which followed our standard approach,^[4–6] is provided in the Supporting Information.