Potassium channel selectivity filterPDB ID: 1K4C
Potassium channels allow potassium ions to pass through membranes. This structure shows the membrane-crossing portion, with a specific arrangement of oxygen atoms that provides the selectivity for potassium.
Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution.
Zhou, Y., Morais-Cabral, J.H., Kaufman, A., MacKinnon, R.
Journal: (2001) Nature 414: 43-48