Fig. 4: The permeation pathway of α6β4 receptors.
From: Molecular insights into the α6β4 nicotinic acetylcholine receptor function and ligand recognition
a Comparison of the structures of α6β4nico and α6β4teb. The α6β4nico and α6β4teb are colored green and purple, respectively. b M2 α-helices from opposing α6 (burgundy) and β4 (blue) subunits with the sidechain shown for pore-lining residues. Purple spheres indicate pore diameter over 5.6 Å; green spheres are 2.8–5.6 Å. c Pore radius for the α6β4nico, α6β4teb, α3β4 (PDB accession: 6pv7) and α4β2 (PDB accession: 6cnj). The zero value along the y-axis of the plot is aligned with the α-carbon of the −1 position. d Position of water pentagons in the pore and corresponding density, viewed in parallel (Top) and perpendicular (Bottom) to the membrane. Opposing α6 and β4 subunits with the sidechain shown for pore-lining residues are colored burgundy and blue, respectively. The water is shown as spheres and colored in red.
