Figure 5.

The influence of C98–C107 disulfide bond on the orthosteric binding of CB₁R. (A) PDB id:5XR8 structure with no disulfide bond; (B) PDB id:5U09 structure with disulfide bond present. In 5XR8 structure the residues F102 and M103 are outside of the orthosteric binding site; the ligand’s position is shallower and there is much more space available in the orthosteric binding site so the ligand has more freedom and is in contact with many water molecules. In 5U09 structure the residues F102 and M103 are inside the orthosteric binding site; the ligand is positioned deeper, surrounded by hydrophobic residues and the binding is tighter.