The interaction energy with the Asp-164 is found in all selected poses for the five ligands; in particular, Lig-03 (7RZC), Lig-04 (7SDR) and Lig-05 (7TZJ), due to the high ionic interaction with the protonated tertiary amine of these ligands in physiological conditions. This indicates the important role of Asp-164 which acts as an anchor for stabilizing the ligands in the binding site. This suggests that the tertiary amine or a protonated function group at this position can increase the affinity of active hits.