Regensburg 2019 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 2: Membranes and vesicles I (joint session BP/CPP)
BP 2.3: Vortrag
Montag, 1. April 2019, 10:00–10:15, H10
Mechanisms of Interactions between Lipid Membranes in the Presence of Biological Cosolutes — •Amanuel Wolde-Kidan1, Quoc Dat Pham2, Alexander Schlaich3, Emma Sparr2, Roland Netz1, and Emanuel Schneck4 — 1Freie Universität, Berlin, Germany — 2Lund University, Lund, Sweden — 3Laboratoire Interdisciplinaire de Physique, Grenoble, France — 4Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
Lipid membranes form the diffusional barrier of eukaryotic cells and determine processes when cells come into close contact, for example during cell fusion or vesicle formation. We analyze the effects of three cosolutes on membrane interactions, which are all abundantly found in biological systems, namely urea, TMAO and sodium chloride. The effect of the polar solutes urea and TMAO on protein stability has been studied extensively, but their influence on lipid bilayers has only recently started to be investigated. Using atomistic molecular dynamics simulations and theoretical modeling we analyze different mechanisms of lipid-solute and lipid-lipid interactions. By means of solution thermodynamics we model the effect of the cosolutes on the hydration repulsion between lipid bilayers. Results from our simulations compare well to experimental calorimetric measurements. We find that the osmotic pressure due to the added solute has the most important influence on the hydration repulsion. Furthermore, we find that the interaction mechanism of sodium chloride with lipid bilayers is dominated by the ion-membrane potentials of mean force. Other factors such as the dielectric response seem to be of less importance.