Dynamics of K⁺ ion conduction through Kv1.2

The crystallographic structure of a potassium channel, Kv1.2, in an open state makes it feasible to simulate entire K⁺ ion permeation events driven by a voltage bias and, thereby, elucidate the mechanism underlying ion conduction and selectivity of this type of channel. This Letter demonstrates that molecular dynamics simulations can provide movies of the overall conduction of K⁺ ions through Kv1.2. As suggested earlier, the conduction is concerted in the selectivity filter, involving 2-3 ions residing mainly at sites identified previously by crystallography and modeling. The simulations reveal, however, the jumps of ions between these sites and identify the sequence of multi-ion configurations involved in permeation.