TABLE 3.

TMs forming the non-ion substrate binding sites in the representative crystal structures of transporters with LeuT-like structural fold

We consider that a TM is involved in forming a binding site when a heavy atom of any of its residues is within 4 Å of the bound substrate. Note, the nomenclature of the transporter conformational states are not consistently used among different groups. We largely classify the transporter conformations into outward-facing, inward-facing, intermediate, or occluded (“closed”) states.