Fig. 2. Construction of the site-specific GF-sFT conjugate.

(A) Chemoenzymatic synthesis of GF-sFT. sFT is constructed via the mgSrtA-mediated transpeptidation to install a C-terminal Tz group. The following IEDDA reaction of sFT-Tz and GDP-Fuc-Am-BCN gives the final product of GF-sFT. (B and C) Characterization of FT-LPETGG, FT-Tz, and GF-sFT by SDS-PAGE gel and mass spectrometry. (D and E) Self–fucosyl-biotinylation of NK92 cells by cell surface–anchored FT. NK92 cells were incubated GF-sFT (0.2 mg/ml) to install FT on cell surface, followed by wash and incubation with GF-Biotin or GF-Biotin and LacNAc for blocking labeling. (F) Confocal imaging of sFT and HER2 on SKOV3-sFT. BF, bright field. Scale bars, 10 μm.