After clustering, five representative conformations, representing the different clusters, were prepared for the docking study using AutoDock Tools software. AutoDock Vina 1.2.2 was used to dock the ligands to the protein active site defined by H41 and C145 . During the docking calculations for all ligands, a flexible ligand in a flexible active site was maintained. The search box was set to cover the dyad H41 and C145 with size 30 × 30 × 30 Å 3 centered at (25.2, 46.0, 40.6) Å.