Figure 5.

Molecular basis of GABA bound in the orthosteric binding site of GABA ρ1 homology model based on GluCl. (A) GABA bound GABA‐ρ1 homology model based on GluCl, showing loops A–G (labelled in red), and H‐bond interactions formed between GABA and Thr²⁴⁴ and Ser¹⁶⁸, and salt bridges with Arg¹⁰⁴ and Glu¹⁹⁶. Arg¹⁵⁸ and Arg¹⁷⁰ are two important residues for protein stability either by forming interaction within the same subunit or between neighbouring subunits. (B) GABA and aromatic residues (Tyr¹⁰², Tyr¹⁹⁸, Tyr²⁴¹ and Tyr²⁴⁷) forming the aromatic box that stabilizes GABA in the binding site during the channel gating. The Phe¹³⁸ residue may form important interactions as it has a benzene ring system that partially oriented to both the GABA binding site and the adjacent subunit.