Conformational model for ion permeation in membrane channels: a comparison with multi-ion models and applications to calcium channel permeability.
The permeation properties of ion channels existing in several conductive states were analyzed. Each state was represented by the one-ion model. A special emphasis was placed on features, assumed to be indicative of a multi-ion mode of channel occupancy such as a deviation of concentration dependence of channel conductance from the Michaelis-Menten equation, an anomalous mole fraction effect, a strong voltage dependence of ion block and coupling of unidirectional fluxes (anomalous Ussing flux ratio). The conformational model was shown to have all these properties. The ion permeation through voltage-sensitive calcium channels fulfilled all the characteristics of the model proposed.
Mironov
S L
SL
Department of Neurophysiology, Max-Planck-Institute for Psychiatry, Planegg-Martinsried, Germany.
D015220:Calcium Channels / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D004553:Electric Conductivity; D004798:Enzymes / Q000378:metabolism; D007473:Ion Channels / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D007700:Kinetics; D008433:Mathematics; D008954:Models, Biological; D011487:Protein Conformation
D015220:Calcium Channels; D004798:Enzymes; D007473:Ion Channels