The non-selective voltage-activated cation channel from human red cells, which is activated at depolarizing potentials, has been shown to exhibit counter-clockwise gating hysteresis. Here, we analyze this phenomenon with the simplest possible phenomenological models. Specifically, the hysteresis cycle, including its direction, is reproduced by a model with 2×2 discrete states: the normal open/closed states and two different states of "gate tension". Rates of transitions between the two branches of the hysteresis curve are modeled with single-barrier kinetics by introducing a real-valued "reaction coordinate" parametrizing the protein's conformational change between the two states of gate tension. The resulting scenario suggests a reanalysis of former experiments with NSVDC channels.
Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory, 2012, Vol 43, Issue 11, p. 2117-2140