Residue-specific N-terminal glycine to aldehyde transformation renders analytically pure single-site labeled proteins.

Here, we present N-Gly-specific glyoxamide generation in native proteins, isolated or in a complex mixture. The resulting aldehyde enables parallel installation of probes and a purification platform to render analytically pure single-site tagged proteins. It renders N-Gly engineered insulin without perturbing its structure, receptor binding, and downstream signaling pathway.

Protein inspired chemically orthogonal imines for linchpin directed precise and modular labeling of lysine in proteins.

We report a chemoselective, site-selective, and modular technology for precision engineering of high-frequency lysine residues in native proteins. It enables a unique, unexplored reactivity landscape on the protein surface to facilitate their single-site modification. Further, the method presents bond-architecture flexibility and enables orthogonal tagging with probes of interest.