Figure 1.

Stereo representation of the ligand-binding pocket of the crystal structure of the hRARγ LBD with the bound active enantiomer BMS270394 (shown in orange). The final model is depicted with the ligand fitted to the electron density map (colored in red) that has been calculated at the very beginning of the refinement in absence of the ligand. The σ_A-weighted F_obs − F_calc map (18) at 1.59-Å resolution is contoured at 3.2 σ. Distances in yellow indicate hydrogen bonds and salt bridges between ligand and residues, whereas van der Waals contacts are shown in blue. RARγ selectivity of the ligand is achieved by its hydroxyl group, which forms a hydrogen bond with the sulfur of Met-272, corresponding to isoleucines in RARα and β. H3, H5, H10, and H11 indicate helices, and L6/7 the loop between helix 6 and 7.