Structural and molecular insight into the pH-induced low-permeability of the voltage-gated potassium channel Kv1.2 through dewetting of the water cavity
Fig 3
Pore closure due to protonation of the two key residues E327 and H418 in the Kv1.2 channel.
(A) The structures of the open and closed Kv1.2 channel. Here, the ribbons represent the pore domain of Kv1.2 channels, the blue spheres denote water molecules, and the gray spheres denote potassium ions. The upper panel illustrates the bottom view of the open and closed conformations. The lower panel shows the wetted and dewetted water cavity in the channel. Both the two opposite subunits and lipid molecules have been omitted from the lower panel. (B) The time evolution of the number of water molecules in the water cavity of the WildUnP or Ep327/Hp418 states of the Kv1.2 channel. The five individual plots in each state represent the simulation results from each trajectory of our MD simulations. In addition, the red horizontal line separates the wetted state from the dewetted state of the water cavity. (C) The distributions of the number of water molecules in the water cavity. The left region with fewer water molecules corresponds to the dewetting condition, whereas the right region with many water molecules corresponds to the wetting condition.