[Structural and functional features of membranes with different cholesterol content].

The paper deals with the present-day ideas of the structure and functions of membranes with different cholesterol content and relative sterols. The data on the molecular bases of lipids and sterols interaction in model systems, monolayers and liposomes, are obtained using 1H-, 13C-, 31P-NMR, EPR-investigations, methods of differential scanning calorimetry and X-ray diffraction. The methods for obtaining biomembranes with the different content of cholesterol and its effect on the membrane structure and functions are discussed. Reasons are analyzed of principal differences in behaviour of biomembranes with different content of cholesterol and respective model systems. The nature of cholesterol binding with phospholipids, proteins and its asymmetric distribution in biomembranes is considered. The cholesterol effect on the erythrocyte membrane charge density and possible changes in structural and functional properties of the membranes are demonstrated through the author's own experimental data. It is concluded that the cholesterol effect on structure and functions of the membranes is determined to a considerable extent by their phospholipid composition, localization and phase behaviour of phospholipids and sometimes depends on the membrane charge density.