Figure 1. Schematic Representation of the Simulation System Constructed on the Basis of the Cryo-EM Structure of nAChR at 4 Å Resolution.

nAChR is embedded in a DPPC lipid bilayer (green) and water molecules (red). Only three subunits (color-coded in red, blue, and yellow) are displayed for clarity. The M2 helices are rendered with electrostatic potential surface to highlight the pore shape.