Solubilization of membrane proteins in ethanol: new perspective method for isolation of ion channels

摘要

Abstract: In spite of the successful use of detergents for the solubilization of a number of membrane proteins, this approach has some restrictions. It is mainly due to difficulties in removing detergents from the proteins which can influence the structure and function of the isolated proteins and interfere with channel activity measurements under the reconstruction of the proteins into lipid bilayers. We have developed a method using ethanol for the extraction of membrane proteins. The dielectric constant of ethanol is between those of water and carbohydrates which aids it to penetrate into the membrane between protein and lipids. This decrease the binding of lipids to proteins and promotes protein solubilization. We have applied this approach to the isolation and reconstitution in lipid bilayer of the large subunit of the (Na$+$PLU$/, K$+$PLU$/)- ATPase from microsomes and from mitochondria: two Ca$+2$PLU$/-channels, thermogenin and the K$-ATP$/ channel. The properties of these channels remained native. !32