A Naturally Encoded Dipeptide Handle for Bioorthogonal Chan–Lam Coupling

Manipulation of biomacromolecules is ideally achieved through unique and bioorthogonal chemical reactions of genetically encoded, naturally occurring functional groups. The toolkit of methods for site‐specific conjugation is limited by selectivity concerns and a dearth of naturally occurring functional groups with orthogonal reactivity. We report that pyroglutamate amide N−H bonds exhibit bioorthogonal copper‐catalyzed Chan–Lam coupling at pyroglutamate‐histidine dipeptide sequences. The pyroglutamate residue is readily incorporated into proteins of interest by natural enzymatic pathways, allowing specific bioconjugation at a minimalist dipeptide tag. Proteinmodifizierung: Die Pyroglutamat‐Histidin‐Dipeptidsequenz zeigt eine erstaunlich schnelle und effiziente kupferkatalysierte N‐H‐Kupplung mit Boronsäuren. Die Reaktion ermöglicht eine spezifische und bioorthogonale Funktionalisierung an einer natürlichen posttranslationalen Modifikation.