THE ROLE OF WATER IN BIOMEMBRANE STRUCTURES

Biomembranes are composed of lipids, proteins and carbohydrates (glycolipids and glycoproteins). The basic structure is generally a lipid bimolecular sheet in which the integral proteins are embedded The relationship between water structure and these various components is most important for determining the final biomembrane structural arrangement. In this presentation the interaction between water and some of these individual biomembrane components are described. The phospholipid-water interaction and the different phases which can exist - lamellar, hexagonal and cubic, and their relevance to biomembrane structure and function, are described The role of bound water, it's detection and properties are outlined, using deuterium NMR spectroscopy and calorimetry, for example. A hydrophobic environment is particularly important for retaining the structure of membrane proteins. The known structure, based on various physical techniques of some of these proteins, is shown. In particular, the application of FTIR spectroscopy for the study of membrane proteins and the detection of water channels with the glucose transporter proteins is described. The effects of dehydration on membranes and the use of various molecules, e.g. trehalose, to overcome the adverse effects of dehydration, are indicated.