Extended Data Fig. 1: Expression, characterization and purification of GABAB.
From: Structural basis of the activation of a metabotropic GABA receptor
a, b, Cell surface expression of Halo–GB1 (a) and SNAP–GB2 (b), transfected alone or cotransfected with the second subunit, measured by the fluorescence emission of the Lumi4-Tb bound to the Halo (a) or SNAP tag (b). Values are normalized by the wild-type GB1 cotransfected with wild-type GB2 (purple bar) and shown as mean ± s.d. of three biologically independent experiments. GABAB constructs for cryo-EM are expressed and function similarly to the wild-type receptor. c, d, Positive allosteric effect of GS39783 (5 μM) on IP1 accumulation in cells expressing wild-type or cryo-EM constructs of GABAB heterodimers and activated either by GABA (c) or SKF97541 (d). Data are normalized by the wild-type response in absence of GS39783 (control) and shown as mean ± s.e.m. of three biologically independent experiments (4 for wild type). e, Representative SEC profile of apo GABAB in digitonin micelles. Dimeric fractions were pooled, supplemented with ligand and concentrated for cryo-EM imaging. f, Coomassie stained SDS–PAGE profile shows two distinct bands for GB1 (86 kDa) and GB2 (88 kDa). For gel source data, see Supplementary Fig. 1.
