Alignment of protein sequences from GluCl, GLIC, ELIC and the human α₁, β₂, and γ₂ GABA_AR subunits.

<p>The GluCl sequence was used as template for homology modeling throughout the GABA_AR subunits, and ELIC was included as a template in the regions marked with blue boxes. The secondary structure deduced from the X-ray structure of GluCl is shown above the alignment (red shapes denote α-helices, and green arrows denote β-strands), whereas historically assigned loop regions are indicated below the alignment. As in the GluCl structure the M3–M4 intracellular loop of GABA_AR sequences was replaced by an AGT tri-peptide linker. Residues comprising the binding sites (within 8 Å of Glu in the GluCl structure and pointing towards the binding site) are colored pink (Glu and GABA binding site) and cyan (BZD binding site). Binding site residues conserved with respect to the templates are indicated as follows: <b>+</b> conserved in both GABA and BZD binding sites; <b>*</b> conserved in the GABA binding sites; <b>.</b> conserved in the BZD binding site. For details on calculation of binding site sequence identities see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0052323#pone.0052323.s002" target="_blank">Figure S1</a>.