(A) Dezocine (magenta) sits in the preformed ligand binding pocket for selective serotonin reuptake inhibitors in the model of human serotonin transporter. The key interacting residues lining the pocket (Y95, D98, I172, Y176, F335, F341, and S438) are in yellow. This binding pocket has been demonstrated to be the binding site for many important clinical drugs such as fluoxetine, sertraline, and amitriptyline. (B) Dezocine (magenta) shares the same binding pocket and overlaps well with desiprimine (orange), the ligand in the LeuT crystal structure (2QJU).