FIG 3.

Comparative analysis of enzyme processivity of WT RT and RT enzymes containing the W153L substitution, alone or in combination with other mutations. The processivity of purified recombinant RT enzymes was analyzed using 5′-end-labeled DNA primer (D25) annealed to a 471-nt HIV-1 PBS RNA template as the substrate; the resulting full-length DNA is 471 nt in length. Processivity was determined by the size distribution of DNA products in fixed-time experiments at 5 μM dNTP in the presence of heparin trap. The sizes of some fragments of the ³²P-labeled 25-bp DNA ladder in nucleotide (nt) bases are indicated on the left side of the panel. All reaction products were resolved by denaturing 6% polyacrylamide gel electrophoresis and visualized by phosphor imaging. The position of the ³²P-labeled D25 primer is indicated on the right. The image is representative of three independent experiments, in all of which similar results were obtained.