Dresden 2017 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 38: Membranes and Vesicles I

BP 38.10: Vortrag

Mittwoch, 22. März 2017, 12:30–12:45, HÜL 386

Molecular Dynamics Simulations Elucidate the Tight Cohesion between Glycolipid Membranes — Matej Kanduc^1,2, Alexander Schlaich², Alex de Vries³, Juliette Jouhet⁴, Eric Maréchal⁴, Bruno Demé⁵, Roland Netz², and •Emanuel Schneck⁶ — ¹Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin (Germany) — ²Freie Universität Berlin (Germany) — ³University of Groningen (The Netherlands) — ⁴CEA Grenoble (France) — ⁵Institut Laue-Langevin, Grenoble (France) — ⁶Max Planck Institute of Colloids and Interfaces, Potsdam (Germany)

Membrane systems that naturally occur as densely packed membrane stacks contain high amounts of glycolipids whose saccharide headgroups display multiple small electric dipoles in the form of hydroxyl groups. Experimentally the hydration repulsion between glycolipid membranes is of much shorter range than that between phospholipids whose headgroups carry single large electric dipole due to the zwitterionic charge distribution. Using solvent-explicit Molecular Dynamics simulations and accounting for the water chemical potential, we quantitatively reproduce the experimentally observed, different pressure-versus-distance curves of membrane stacks composed of phospholipids and of the glycolipid digalactosyldiacylglycerol (DGDG). We show that the short-ranged water uptake into the glycolipid membranes is solely driven by the hydrogen-bond balance involved in non-ideal water/sugar mixing. Water structuring effects and lipid configurational perturbations, responsible for the more long-ranged repulsion between phospholipid membranes, are inoperative for the glycolipids.