Hydration repulsion between biomembranes results from an interplay of dehydration and depolarization

Emanuel Schneck, Felix Sedlmeier, and Roland R. Netz – 2012

Hydration repulsion dominates the interaction between polar surfaces in water at nanometer separations and ultimately prevents the sticking together of biological matter. Although confirmed by a multitude of experimental methods for various systems, its mechanism remained unclear. A simulation technique is introduced that yields accurate pressures between solvated surfaces at prescribed water chemical potential and is applied to a stack of phospholipid bilayers. Experimental pressure data are quantitatively reproduced and the simulations unveil a rich microscopic picture: Direct membrane–membrane interactions are attractive but overwhelmed by repulsive indirect water contributions. Below about 17 water molecules per lipid, this indirect repulsion is of an energetic nature and due to desorption of hydration water; for larger hydration it is entropic and suggested to involve water depolarization. This antagonistic nature and the presence of various compensating contributions indicate that the hydration repulsion is less universal than previously assumed and rather involves finely tuned surface-water interactions.

Titel
Hydration repulsion between biomembranes results from an interplay of dehydration and depolarization
Verfasser
Emanuel Schneck, Felix Sedlmeier, and Roland R. Netz
Datum
2012
Kennung
10.1073/pnas.1205811109
Zitierweise
Proc. Natl. Acad. Sci. USA, 2012, 109, 14405 - 14409
Art
Text
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