Extended Data Fig. 6: Vestibular glycans and interface classes in the α1β3γ2L GABA_A receptor.

a, Side view of the receptor shows the position of vestibular α1 N-linked glycans. For clarity, the near α1 and β3 subunits have been removed. b, View across the extracellular vestibule reveals the stacking of α1 N-linked glycans. The receptor surface is coloured according to electrostatic surface potential and reveals an electropositive ring in the middle portion of the ECD vestibule. c–f, Paired views of the interface between principle (+) and complementary (−) subunits viewed from the pore axis outwards (left) and open-book view of each subunit when viewed from the receptor periphery (right). Residues involved in forming interactions (defined using PDBePISA⁴⁵) are coloured according to the type of interaction and mapped onto the isosurface representation: polar, cyan; electrostatic/salt bridges, magenta; van der Waals, orange. Arrowheads reveal the openings of defined tunnels between adjacent subunits. g, Calculated interfacial buried surface areas and solvation energy gain at complex formation (both calculated using PDBePISA⁴⁴). The asterisk denotes the second β3/α1 (chain E/chain A) interface in the pentameric assembly. Radii of tunnels, denoted by arrowheads in c–f, were also calculated (see Methods). Open arrowheads in c, e denote cavities forming the proposed anaesthetic-binding sites.