FIGURE 3.

Effects of cavity mutations on de novo and elongation RdRp activities. A, de novo RdRp activities of mutant NS5 proteins. B, elongation RdRp activities. The elongation assay measured the fluorescence generated by using a substrate mimic BBT-ATP and RNA template, as reported previously (26). Results are the average of two independent experiments performed in duplicate. C, summary of de novo and elongation RdRp activities. The relative de novo RdRp activities were calculated by comparing the products generated using the mutant NS5 proteins with that produced using the WT protein (set as 100%). The relative RNA elongation activities were calculated by comparing the slope from the mutant NS5 proteins with that of the WT protein (set as 100%).