Table 2. Differences of calculated free energy between modelsa (energy unit: kcal/mol).

	Ligand 1	Ligand 2	Ligand 3	Ligand 4
ΔGL_solvation	−18.31	−18.40	−20.23	−16.36
Full Model ΔΔG	0.0	6.58	3.73	4.12
No Arg-1208 ΔΔG	0.0	0.18	4.14	2.17
No Tyr-1230 ΔΔG	0.0	7.67	3.28	3.77
No Met-1211 ΔΔG	0.0	7.48	4.05	3.85
No Asp-1222 ΔΔG	0.0	5.70	2.54	3.50

^a The value of free energy difference is obtained by using the models containing ligand 1 as reference.