Fig 3.

Inhibition of polymerization by the various NRTI-TPs. The assay was done as described in Materials and Methods. Normal dNTPs were present in the reaction mixture at 10.0 μM each. Increasing concentrations of the triphosphate form of the analog were added as shown. The amount of full-length product in the absence of analog was considered 100% activity; the other reactions were normalized to this value. The amount of full-length product in the absence of any NRTI-TP was considered 100% activity. The activity with the NRTI-TPs was normalized to that value. The percentage of full-length product was calculated by determining the amount of primer that was extended to the end of the template and dividing this amount by the amount of all extension products (full-length and NRTI-MP-blocked primers). Assays were done in triplicate. The error bars represent the standard deviation. (A) Inhibition by AZTTP on a DNA template/DNA primer. (B) Inhibition by AZTTP on an RNA template/DNA primer. (C) Inhibition by ddATP on a DNA template/DNA primer. (D) Inhibition by ddATP on an RNA template/DNA primer. (E) Inhibition by ddCTP on a DNA template/DNA primer. (F) Inhibition by ddCTP on an RNA template/DNA primer.