Regensburg 2016 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 65: Membranes and Vesicles II

BP 65.3: Vortrag

Donnerstag, 10. März 2016, 15:45–16:00, H43

A new free energy-based lattice model of lipid membranes — •Andreas Heuer and Davit Hakobyan — Institute f. Phys. Chemistry, WWU Münster

The thermodynamic properties of lipid mixtures in membranes are, on the one hand, strongly influenced by the specific enthalpic interactions among lipids and, on the other hand, by the entropic degrees of freedom of the hydrocarbon chains [1]. We suggest the formulation of a lattice model, each site corresponding to one lipid, where the enthalpic and the entropic effects are taken into account in a quantitative way. The chain entropy is reflected by an appropriately chosen order parameter distribution. All properties of the lattice model are extracted from atomistic molecular dynamics simulations of saturated and unsaturated lipids, respectively.

We can show via kinetic Monte Carlo simulations that the lattice model displays on a quantitative level the same temperature effects as the atomistic system. Specifically, we discuss gel formation for the pure saturated lipid and phase separation for a mixed system upon cooling. This agreement reflects the fact that the different free energy contributions of the atomistic system are contained in the lattice model.

[1] D.Hakobyan, A. Heuer, PLoS ONE 9/2, e87369 (2014).