The residues cysteine and lysine are the undisputed champions of bioconjugation chemistry. Targeting other amino acids has been touted as a potential way to improve the synthesis of protein–peptide and protein–protein conjugates that are widely studied for their potential therapeutic ability and used as tools for understanding biological function. Now, a team of researchers at the University of California, Berkeley, have targeted solvent-exposed tyrosine residues to develop a method of preparing such conjugates.