We obtained a MM-GB/SA score, which measures the binding free energy in ligand-protein complex at single point using the MMGB/SA method in the Prime program (Prime MMGBSA v3.000) . The docked poses were minimized around amino acids within 3Å from the inhibitors using the local optimization feature in Prime and the energies of the complexes were calculated using the OPLS4 force field and GB/SA continuum solvent model (Figure ). The binding free energy (Gbind) was then estimated using the equation: