Dynamics of Membrane Proteins by Magic Angle Spinning Solid State NMR. Annual Reviews of Biophysics

Ion binding in a potassium ion channel is studied in membrane bilayers, yielding insights into inactivation. At high potassium the selectivity filter is in a conductive form, and at low potassium it collapses into a long-lived nonconductive structure with reduced ion occupancy. New solid state NMR methods are applied to full length wild type channel and to the inactivation-less mutant E71A to test the hypothesis that an important channel-inactivation process, known as C-type inactivation, has as its central step the evacuation of ions from the selectivity filter. Furthermore, ion affinity is allosterically coupled to pH triggered opening of the channel