Neurotransmitter and psychostimulant recognition by the dopamine transporter.

Epitope residues were calculated from [PDB: 4XPB and 4XPT] as the antigen residues at 4 Å atomic distance from the antibody. Contact residue Q163 is only in PDB: 4XPB and contact residues R158, V202 and E206 are only in PDB: 4XPT. The epitope of 9D5 Fab on the dopamine transporter with cocaine bound was determined from the crystal structure of the complex, solved by molecular replacement. The Fab was used as a chaperone to aid in crystallization. The dopamine transporter construct dDAT(ts2 dDATcryst) has deletions of residues 1-20 and 164-206, a thrombin site (LVPRGS) replacing residues 602–607 and point mutations V74A and L415A to enhance thermostability. In addition the construct has subsiteB mutations D121G (TM helix 3) and S426M (TM helix 8) in the binding pocket.