FIGURE 2.

Inhibition of GFP-intein fusions in vitro. A, fluorescence assay. Fluorescence spectra in the presence of cisplatin from 0 to 10 μm are shown. The arrow indicates decreasing fluorescence intensity with successively higher cisplatin concentrations. B, relative fluorescence intensity as a function of cisplatin concentration. Measurements were performed on GFP (○) and the GFP-intein fusion protein (●). Data are average values from three parallel experiments, and error bars correspond to the standard deviations. C, gel assay of cisplatin inhibition. The concentration of cisplatin (μm) is shown above the lanes of a 12% SDS-polyacrylamide gel, with precursor, spliced GFP, and excised intein labeled. The relative amount of splice products at different cisplatin concentration is shown in Fig. S1.