Figure 2.

Three-dimensional structure of the HIV-1 Vpr protein (from [15]). The three α-helices (17–33, 38–50, 55–77) are colored in pink, blue and orange, respectively; the loops and flexible domains are in green. We can the Trp54 residue localized between the second and the third a-helix, and that is likely accessible for protein-protein interaction with UNG2 [54].