Extended Data Fig. 5: Mb38 binding and function.
From: Cryo-EM structure of the human α1β3γ2 GABAA receptor in a lipid bilayer
a, b, Side (a) and top-down (b) views of neighbouring α1+ and β3− subunits bound to Mb38. c, Representative normalized current traces obtained in cells expressing the α1β3γ2L receptor exposed to GABA (3 μM) alone or with varying concentrations of Mb38 (n = 3–6 cells), applied for 4 s. Currents were normalized to peak-current amplitude obtained with GABA (3 μM) alone during the first 1-s phase of the trace. The concentration of Mb38 is indicated above each trace. d–f, Close-up view of the binding site when viewed approximately parallel to the plane of the membrane. Complementarity-determining-region loops 1 (d), 3 (e) and 2 (f) of the Mb38 are coloured in turquoise, dark green and teal, respectively, and residues involved in interactions are shown in ball-and-stick representation. Polar interactions are shown as dotted lines. g, Representative current trace obtained in cells expressing the α1β3γ2L receptor exposed to 3 μM Mb38. Mb38 (3 μM) opened 16 ± 11% (mean ± s.d.; n = 5 cells) of the receptors gated by EC10 GABA alone (therefore around 2% of the total receptors expressed).
