FIG. 4.

Results of docking ritonavir (RTV), an HIV PR inhibitor, to wild-type and “HIV-inized” FIV PR. The conformation with the best docking energy in each case is shown: the wild-type (wt) FIV PR is in light grey, while the HIV-inized quadruple mutant of FIV PR (I37³²V/N55⁴⁶M/M56⁴⁷I/V59⁵⁰I) is shown in dark grey, as are the corresponding conformations of ritonavir. Note that the catalytic aspartic acids are also visible at the base of the active site. The conformation of ritonavir is similar from sites P2′ to P2 but differs significantly at the P3′ site.