Figure 2. Characterization of the biosensor.
Left panel, the emission spectra (λex = 437 nm) of the purified biosensor (100 pmol) before and after its cleavage for 1 h at 37°C using purified furin (10 fmol and 100 fmol). RFU, relative fluorescence unit. Middle panel, the time course of the ECFP/YPet emission ratio (476 nm/526 nm at λex = 437 nm) of the biosensor (100 pmol) incubated for 4 h at 37°C with or without furin (10 fmol and 100 fmol). Right panel, a ratiometric response of the normalized ECFP/YPet emission ratio to the increasing concentrations of furin. Incubation time, 1 h. These experiments were repeated multiple times with similar results. The representative experiments are shown.