Fig. 8. Central binding site (side view) of PDB 4XP9 (grey, dDAT with d-amphetamine), ; 4XPA (grey, dDAT with 3,4-dichlorophenethylamine), ; 4MM4 (light blue, LeuBAT with paroxetine) and ; 5I6X (mint, hSERT with paroxetine), pointing out the vicinity of the cationic nitrogen to the carbonyl oxygen of Tyr95 (hSERT), Phe43 (dDAT) and Tyr21 (LeuBAT), respectively. The marked distance of 2.93 Å is measured in ; 4MM4.