Dresden 2017 – scientific programme
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BP: Fachverband Biologische Physik
BP 38: Membranes and Vesicles I
BP 38.10: Talk
Wednesday, March 22, 2017, 12:30–12:45, HÜL 386
Molecular Dynamics Simulations Elucidate the Tight Cohesion between Glycolipid Membranes — Matej Kanduc1,2, 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.