FIGURE 6.

Views of the CYP46A1 active site illustrating interactions with VOR. A, shown are residues in contact with VOR and a network of bound H₂O molecules. Portions of the secondary structure are also shown. B, superposition of VOR-bound (pale green) and ligand-free (wheat) structures show the active site volumes and conformational changes that accommodate binding of the VOR molecule. The heme group in VOR-bound and ligand-free CYP46A1 is in warm pink and red, respectively, and VOR is in light pink. The nitrogen, oxygen, iron, and fluorine atoms are in blue, red, orange, and light blue, respectively. H₂O molecules are shown as red spheres. Dashed black lines indicate hydrogen bonds. The solvent-occupied surface of the active site is shown in green mesh in VOR-bound CYP46A1 and a wheat surface in ligand-free P450.