FIGURE 1.

Structural formulae of the eight ligands used in the calculation. Ligands 2, 5, 6, 8, and 9 have one or two physically symmetric units (phenyl or cyclohexyl group). Flat-bottom dihedral restraints were applied on these symmetric units to prevent exchange between physically equivalent conformers. Ligand 20 is also referred to as FK506 in the literature (60). The atoms labeled in red and blue are the atom used to define the point-positions L₁ and L₂, respectively in Fig. 3.