Orientations of GABA, ALA and MAL in the central substrate binding pocket.

<p>a) GABA in all four GAT models, b) GABA and ALA in GAT-2, and c) GABA and MAL in GAT-2. Amino acids in positions 1.47 (G), 3.50 (Y) and 6.53 (F) are conserved among the GAT subtypes, whereas the amino acids in positions 1.42 (Y in GAT-1; E in the others) and 6.59 (Q in BGT-1, L in the others) are non-conserved. Intermolecular hydrogen bonds are shown as dotted lines; the thickness of the lines representing the energy of the interaction. Amino acid side chains are shown in wire representation, ligands in yellow xstick representation, and Na1 sodium ion as blue sphere. Color coding of atoms: blue: nitrogen; red: oxygen.