Fig. 3
From: Cryo-EM reveals ligand induced allostery underlying InsP3R channel gating
Conformational changes in the ion conduction pathway upon ligand binding. a Solvent-accessible pathway along the pore mapped using the program HOLE75 for Apo- (light purple) and AdA-bound (green) InsP3R1. A series of residues within the ion conduction pathway of the channel pore are labeled. b Comparison of pore diameter for Apo- (light purple) and AdA-bound (green) InsP3R1. c–d Sections of density maps perpendicular to the four-fold axis at the position of F2586 (c) and I2590 (d) are shown overlaid with their corresponding models and viewed from the cytosol; Apo-InsP3R1 model is shown in light purple, AdA-InsP3R1 is shown in green; distances between the sidechains from two opposing TM6 helices are indicated; corresponding side-chain rotations are indicated in the right panels. e Zoomed-in views of the bulge in TM6 seen in AdA-InsP3R1 (green) overlaid on TM6 from Apo-InsP3R1 (light purple). The lower panel represents a ~ 40° rotation in view from the upper panel
