Ion channel gating: insights via molecular simulations

Ion channels are gated, i.e. they can switch conformation between a closed and an open state. Molecular dynamics simulations may be used to study the conformational dynamics of ion channels and of simple channel models. Simulations on model nanopores reveal that a narrow (< 4 Angstrom) hydrophobic region can form a functionally closed gate in the channel and can be opened by either a small (similar to1 Angstrom) increase in pore radius or an increase in polarity. Modelling and simulation studies confirm the importance of hydrophobic gating in K channels, and support a model in which hinge-bending of the pore-lining M2 (or S6 in Kv channels) helices underlies channel gating. Simulations of a simple outer membrane protein, OmpA, indicate that a gate may also be formed by interactions of charged side chains within a pore, as is also the case in CIC channels. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.