Dual-color Imaging of Cell-Surface and Intracellular Proteins Using Fluorescent Probes for β-lactamase Tag

We herein develop a fluorescein-conjugated β-lactamase inhibitor-based probe, FD-DA, with expanded emission color for labeling proteins through β-lactamase tag. FD-DA specifically labeled intracellular target proteins in live cells after hydrolysis of the ester groups. In combination with a red-fluorescent cell-impermeable probe, dual-color imaging of intracellular and cell surface β-lactamase-tagged proteins was achieved via discriminative labeling.