Figure 3: The role of water in Clˉ permeation in the open state AMOEBA simulations.

A Cross-section schematic of the protein fragment of the open state bestrophin (PDB ID 8D1O) with the neck residues illustrated in licorice representation. B The pore radius profile of the open state fragment. The outer grey dashed lines represent the extent of the protein and the central lines indicate the z-location of the neck residues where z is the distance down the axis of the pore and z = 0 corresponds to the C_α of F80. C The first hydration shell of Clˉ as a function of z. The shaded orange region represents the standard error in hydration number at a given z. Snapshots exemplifying the first hydration shell (blue spheres) of Cl⁻ (orange spheres) in D the bulk-like water regime within the protein fragment. E The partial loss of hydration shell due to anion-π interactions with the aromatic rings of F80 rotated inwards towards the pore axis. F The partial loss of Clˉ hydration due to anion-π interactions with the aromatic rings of F80 oriented outwards as in the experimental structure conformation.