SIMPLE-MODEL OF DEHYDRATION TRANSITIONS IN LAMELLAR SYSTEMS, SUCH AS LIPID-MEMBRANES

A simple, exactly solvable ''Gaussian'' model for the hydrophilic surfaces with an intrinsic lateral periodicity is introduced. This model describes the crossover from a repulsive mode of the hydrational interaction between such surfaces to an attractive one. The resulting transition takes place gradually upon decreasing temperature. Even more importantly, this transition is promoted by the frustration of the water structure near the surfaces and by the increased water binding to the hydrophilic surface residues. Model conclusions and experimental conditions under which the dehydration transitions occur, or might occur in the lipid lamellar systems are discussed.