Fig. 8.

Effects of V82A and V82I substitutions on DRV's activity to inhibit PR dimerization. COS7 cells were cotransfected with the pHIV-PR^CFP and pHIV-PR^YFP pair of plasmids carrying a single V82A or V82I substitution or four combined mutations (V32I, L33F, and I54M plus V82A or V82I). The COS7 cells were further cultured in the continuous presence of 0.1 and 1 μM DRV, and the CFP^A/B ratios were determined at the conclusion of the 3-day period of culture. Note that combined with other three substitutions V32I, L33F, and I54M, V82A did not have a significant effect on DRV's dimerization inhibition activity, while V82I compromised the dimerization inhibition of DRV at 0.1 and 1.0 μM. The differences between the CFP^A/B ratios in the absence of drug (CFP^{A/B_{No Drug}}) and the CFP^A/B ratios in the presence of 1.0 μM DRV (CFP^{A/B_{1.0 DRV}}) had P values of 0.00017 for V82A and 0.0027 for V82I. The differences between the CFP^A/B ratios in the absence of drug (CFP^{A/B_{No Drug}}) and the CFP^A/B ratios in the presence of 0.1 μM DRV (CFP^{A/B_{0.1 DRV}}) and between the CFP^A/B ratios in the presence of 0.1 μM DRV (CFP^{A/B_{0.1 DRV}}) and 1.0 μM DRV (CFP^{A/B_{1.0 DRV}}) were 0.000055 and 0.38 for V32I, L33F, I54M, and V82A and 0.026 and 0.91 for V32I, L33F, I54M, and V82I, respectively.