Table 2. Inhibition of HIV-1 RT Dimerization and DNA Polymerase Activity by Peptides Derived from the β7/β8 Loop.
| IC50 (μM) |
|||
|---|---|---|---|
| Peptide | Dimerizationa | Nucleotide incorporation activityb | DNA polymerization (reassociation assay)c |
| 1 | ND | >145 | ND |
| 2 | ND | >145 | ND |
| 3 | >150 | >145 | ND |
| 4 | 137 ± 34 | >145 | >250 (<5) |
| 5 | 61 ± 15 | >145 | >250 (43) |
| 6 | 37 ± 14 | 109.4 ± 30.8 | 203 ± 35 |
Values were determined with the FLAG-p66/His-p51 dimerization assay.25
Single nucleotide incorporation assays were carried out with D38/25PGA, a 38/25mer DNA/DNA template primer, and wild-type HIV-1 RT. Reported values are the average ± SD of three independent experiments. Nevirapine was used as control in these assays and showed an IC50 of 0.57 ± 0.14 μM.
The amount of polymerized DNA was determined after addition of [3H]dTTP, using poly(rA)/oligo(dT)16 as template-primer. The RT was preincubated with the corresponding inhibitor, in the presence or absence of 14% acetonitrile for 15 h at 37 °C. Before adding the nucleotide, acetonitrile concentration was reduced to <1% to measure the amount of reassociated heterodimer through its enzymatic activity. Reported values are the average ± SD of three independent experiments. Numbers within parentheses represent the percentage of inhibition at 200 μM. ND, not determined.