Extended Data Fig. 3: GABAAR reconstruction details.
a, The GABAAR cryo-EM map viewed from the extracellular space (top view). The density of one subunit of the homopentamer is highlighted in yellow; glycans are orange; the nanobody domain of Mb25 green; and the lipid nanodisc light blue. b, As in a, but viewed parallel to the plasma membrane space (side view). c, Stacking of histamine with aromatic residues in the ligand-binding pocket. Water molecules removed for clarity. d, Radiation damage in the ligand-binding pocket illustrated by difference maps of Asp43 and Glu155 carboxyl groups. e, Radiation damage causes partial reduction of the disulfide bond between Cys136 and Cys150. Left panel: oxidized state, right panel: reduced state. Only Cα, Cβ and sulfur atoms depicted for clarity. f, Difference map revealing the hydrogen bonding network between β-strands. g, A close-up view of the lipids (blue) surrounding the transmembrane region of the receptor. Compared to a, b, the contour level is decreased. Red arrow indicates section level as depicted in h. The general anaesthetics pocket and the neurosteroid modulation site are indicated by the red circle and rectangle, respectively. h, Top-view of a transverse section through the GABAAR transmembrane region shows semi-ordered lipids surrounding individual subunits. i, Close-up view of the general anaesthetics pocket. j, Close-up view of the neurosteroid modulation site. Lipids in i and j could not be identified unambiguously and therefore are modelled as aliphatic chains.
