FIG. 6.

Comparison of the modulating effects of imidazo[4,5-d]pyridazine nucleosides on the ATPase and helicase activities of WN virus NTPase/helicase. The ATPase (A) and helicase (B) reactions were performed in the presence of increasing concentrations of HMC-HO4 (dashed line), HMC-HO5 (▾), and HMC-HO1α (▪). In both assays, the compounds were added to the reaction mixture simultaneously with the enzyme. The reactions were performed and the enzymatic activities were determined by the procedures described in Materials and Methods. The activities of the enzyme measured in the absence of the compounds were referred to as 100%. The results shown are representative of those for three independent experiments.