Sterically Shielded, Stabilized Nitrile Imine for Rapid Bioorthogonal Protein Labeling in Live Cells.

ABSTRACT: In pursuit of fast bioorthogonal reactions, reactive moieties have been increasingly employed for selective labeling of biomolecules in living systems, posing a challenge in attaining reactivity without sacrificing selectivity. To address this challenge, here we report a bioinspired strategy in which molecular shape controls the selectivity of a transient, highly reactive nitrile imine dipole. By tuning the shape of structural pendants attached to the ortho position of the N-aryl ring of diaryltetrazoles-precursors of nitrile imines, we discovered a sterically shielded nitrile imine that favors the 1,3-dipolar cycloaddition over the competing nucleophilic addition. The photogenerated nitrile imine exhibits an extraordinarily long half-life of 102 s in aqueous medium, owing to its unique molecular shape that hinders the approach of a nucleophile as shown by DFT calculations. The utility of this sterically shielded nitrile imine in rapid (?1 min) bioorthogonal labeling of glucagon receptor in live mammalian cells was demonstrated.

SUBMITTER: An P 

PROVIDER: S-EPMC5901669 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature