Arginine selective reagents for ligation to peptides and proteins.

A new class of arginine-specific bioconjugation reagents for protein labeling has been developed. This method utilizes a triazolyl-phenylglyoxal group on the probe molecule that reacts selectively with the guandinyl group of Arg residues in a protein or peptide. The reaction proceeds in neutral to basic bicarbonate buffers and is selective for arginine residues in peptides and folded proteins. Importantly, the triazolyl-phenylglyoxal group can be introduced into complex molecules containing alkyne groups using CuAAC chemistry, providing a robust approach for the generation of phenylglyoxal reactive groups into molecules to be covalently attached onto the surface of proteins.