Shedding Light on Voltage-dependent Gating

Voltage-dependent channels respond to changes in the transmembrane electric field by rearranging their voltage sensors, triggering increases in selective permeability. The channels reside in three types of conformationally distinct populations: closed states, open states, and a variety of inactivated states. These populations are closely interrelated and, while significant advances have been made in understanding these relationships, their quantitative and molecular description has occupied most of the waking hours of channel biophysicists for the last five decades. Initial studies of ion channel gating depended on the ability of channels to conduct ions at rates of 10 6 –10 7