Comparison of extracellular domain of LeuT and SERT in the inward-open and outward-open states.A, the outward-open state of LeuT, yellow (PDB: 3F3A) was superimposed with the inward-open state, brown (PBD: 3TT3). EL4 is shown in solid colors while the rest of the protein is transparent. B, the outward-open paroxetine bound state of SERT, dark green (PDB: 6VRH) was superimposed with the inward-open ibogaine-bound state, light green (PDB: 6DZZ). EL4 is shown in solid colors while the rest of the protein is transparent. Residues that are involved in interaction with 8B6 scFv are shown in sticks.