Fig. 1: Global architecture of 5HT3R-Salipro.
From: Asymmetric opening of the homopentameric 5-HT3A serotonin receptor in lipid bilayers
a Cryo-EM maps of apo- (C5 symmetric, light blue; C1 symmetric, grey) and serotonin-5HT3R-Salipro (5-HT, dark blue), with red, orange, yellow and transparent-yellow densities corresponding to glycosylation, cholesterol, inter-subunit phospholipids and the saposin-lipid bilayer, respectively. b Static pore radius of the 5HT3R-Salipro models determined using HOLE64. Green and blue spheres represent radii of 1.8–3.3 Å, and >3.3 Å, respectively. c, d Superposition of the apo-5HT3R-Salipro (C5) and apo-5HT3R-detergent (6BE1, yellow) structures (single subunit is shown for clarity). Differences at the c MX and M4-MA helices, and d M1 and M3 helices are highlighted. e The TMD thickness was measured between residues L221 and W426 for the 5HT3R-Salipro and the 5HT3R-detergent structures (coloured as in c and f). f Superposition of the monomers of the serotonin-5HT3R-Salipro and serotonin-5HT3R-detergent (6DG8, orange) structures. The left panel shows chain C in colour and black silhouettes for the other chains. The middle panel shows a top view of the TMD. Right panel highlights differences in the position of MX (8.2, 6.7, 10.3, 7.0 and 5.3 Å measured at the Cα atom of W320 of chains A–E, respectively). Chains C and E represent the most and least different subunits, respectively.
