The open-channel structural model of the Torpedo AChR in the context of other structures. Cα profiles of the indicated structural models. The five subunits of each model were averaged. Error bars (omitted if smaller than the symbols) are standard errors. Solid lines are cubic-spline interpolations. In the case of the Torpedo AChR, we applied a residue-numbering correction that accounts for the mis-threading of the amino-acid sequence in the original model (Mnatsakanyan and Jansen, 2013). The lumen of the pore is to the right of the plot.