Inhibition of the helicase activity of HCV NTPase/helicase by 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide-5 '-triphosphate (ribavirin-TP).

In the presented study the ribavirin-TP--an established inhibitor of the NTPase activity of the superfamily NTPase/helicases II--was investigated as an inhibitor of the unwinding activity of the hepatitis C virus (HCV) NTPase/helicase. The kinetics of the reaction revealed that ribavirin-TP reduces the turnover number of the helicase reaction by a mechanism that does not correspond to that of the inhibition of the NTPase activity. Our results suggest that derivatives of ribavirin-TP with enhanced stability towards hydrolytic attack may be effective inhibitors of the enzyme.