Site-Specific Synthesis of Protein-Oligo Conjugates through Histidine-Maleimide-Mediated Imidazolidinone Formation

Protein modifications are crucial for biological applications including detection and therapeutics. Methods that site-specifically modify target proteins are limited and demanding. Here, we present a novel N-terminal labeling technique that improves not only the conjugation efficiency but also the ratio for mono-modification. This technique has been applied to modify multiple protein targets efficiently. In addition, this new linkage was found to be hydrolytically stable under extreme thermal pressure (95 °C heating under aqueous buffer). Of significant note, protein functions including binding and folding properties were retained after conjugation.