In vivo precision imaging of vicinal-dithiol-containing proteins by a FRET molecular probe sensitive to protein environment

We here present a Förster resonance energy transfer (FRET)-based and environment-sensitive fluorescent probe VG-1 for vicinal-dithiol-containing proteins (VDPs). VG-1 uniquely contains two sites sensitive to the protein environment (SPE), thus it shows weak fluorescence in both blue and green channels (a low FRET efficiency) in solution. After specifically binding with VDPs, its fluorescence in the green channel increases, while that in the blue channel disappears, achieving the specific detection of VDPs. The obvious signal changes in fluorescence may be attributed to that the increased rigidity of the molecular skeletons causes the enhanced FRET efficiency. The probe also achieved the cell super-resolution imaging of VDPs and the confocal imaging of VDPs in zebrafish.