Supplementary Materials

Ion permeation in K+ channels occurs by direct Coulomb knock-on

David A. Köpfer, Chen Song, Tim Gruene, George M. Sheldrick, Ulrich Zachariae, Bert L. de Groot

Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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  • Materials and Methods
  • Figs. S1 to S6
  • Tables S1 to S14
  • Caption for movie S1
  • References

Images, Video, and Other Other Media

Movie S1
K+ ion permeation within a 50-ns trajectory from our computational electrophysiology molecular dynamics simulations. For clarity, only two subunits of KcsA are shown. K+ ions are shown as purple spheres. As can be seen from the movie, the knock-on permeation mechanism in the K+ channel is based on close contacts between adjacent K+ ions in the filter, and water molecules are not directly involved in the permeation process under physiological transmembrane voltage (<250 mV in our simulations), even though water is able to access site S4 occasionally.