FIG 10.

Inhibition of VEEV nsP1 methylation and guanylylation activities. (A) Inhibition of VEEV nsP1 methylation was tested by incubating nsP1 with guanylylimidodiphosphate (GIDP), S-adenosyl-[methyl-³H]methionine, and AdoMet in the presence of increasing concentrations of sinefungin, ATA, or ribavirin triphosphate (3P) at 30°C for 1 h. (B) Inhibition of VEEV nsP1 guanylylation was tested by incubating nsP1 with m⁷GTP, AdoHcy, and MgCl₂ in the presence of increasing concentrations of sinefungin, ATA, or ribavirin 3P at 30°C for 1 h. Reaction samples were collected and analyzed by experimental procedures given in Materials and Methods. The data presented are means from three independent experiments, with standard deviations indicted. (C) IC₅₀s of the three compounds are illustrated.