Crystal structures of human FABP7 protein. (A–C) Overall structure of FABP7 protein in apo state (A) and ligand-binding state (B and C). Cholesterol is highlighted as magenta sticks in B, and 25-hydroxycholesterol (25-HC) is highlighted as light orange sticks in C. (D) Superposition of apo (yellow) and cholesterol-bound (green) FABP7 structures. (E) The nuclear magnetic resonance (NMR) or x-ray analysis showing empty or ligand-bound FABP7 with the F58 residue in open and closed conformations. (F) Detailed view of FABP7 interacting with cholesterol (magenta sticks). Hydrogen bonds formed between FABP7 and the hydroxyl group of cholesterol are denoted by red dashed lines. The hydrophobic interactions between FABP7 F58 and cholesterol are shown by black dashed lines. Key residues for cholesterol binding are indicated.