Membrane Proteins as Ion Channels

Abstract

Membrane proteins perform many vitally important functions in cells. The general characteristic of all these proteins is their influence on transport of various effectors,in particular, on ion transport, as a rule, in response to an outer action. For the last two decades we, at the Shemyakin Institute, were engaged in studying the problems of ion transport (1–3). For ionophores, a classical representative of which is valinomycin, the molecule conformation was established and its potential possibilities were elucidated that allowed us to understand the mechanism of action of these compounds. Nowadays more and more information is available on the properties of gramicidin A, the best studied model channel former. Investigations of ion channels are carried out in many laboratories throughout the world by various methods: biochemical, physical, electrophysiological, etchowever, the results obtained are not always in accordance. Their isolation in a pure state is a serious problem and here highly specific effectors are of undoubt benefit. They are also applied in studying the action of membrane channel formers; on the other hand, using such specific ligands, one can succeed in obtaining information on the channel structure.