NMR based structure of Vpr. The NMR-based 3D- structure of Vpr (1–96) is characterised by three α helices in close vicinity surrounded by flexible N and C termini . Helices are presented in dark blue (17–33), green (38–50) and orange (54–77). Mutated amino acids Q3R, L23A, ΔQ44, W54G, I60A, L67A, R77Q and R90K are represented in CPK mode. Noticeably, the NMR studies were carried out on the Vpr sequence of the HIV-1 pNL43 strain with a Leucine at the position 60 instead of an Isoleucine for the HIV-1LAI strain used here. Nevertheless, a predictive study on I60 Vpr showed that the third α helix was not altered compared to L60 Vpr (data not shown).