Biological membranes play a significant role in a range of biological processes such as ion-transport and signal transduction. Over the years much effort has been devoted towards developing an understanding of biomembrane structure. The study of this subject is now reaching an important stage. This is because at last the full three-dimensional structure of certain membrane proteins is beginning to be resolved. In the past three-dimensional structures of membrane proteins were difficult to obtain as only two dimensional crystals were available. In recent years satisfactory crystals have been obtained and X-ray diffraction techniques have been applied. This has led to the ME: S.S. Baig