THE STPUCTURE AND FUNCTIONAL CONFORMATION OF VOLTAGE-GATED ION CHANNELS IN BIOMEMBRANES
生物膜电压门控离子通道的结构和功能性构象

Ion channels in biomembranes have a variaty of the biological functions. In the past several years, the protein components of the voltage-gated Na+, Ca2+, and K+channels have been isolated and purified. Na+ and Ca2+ channels consist of a principal transmembrane subunit with a variadle numder of associated sudunits in different cell types. Amino acid sequences of the principal sudunit in Na+ and Ca2+ channel and the protein of K+ channel have been ditermined, and thier second structures of transmembrane topology have been given. According to the functionnal properties including the voltage sensitivity, opening kinetics, gated currents, and action of neurotoxins, several people have proposed the models of Na+ channel relating the functional three dimensional conformation. Coordinated application of biochemical, biophysical, and molecular genetic methods should lead to a clear understanding of the molecular mechanism of electrical excitadility.