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BP: Fachverband Biologische Physik

BP 21: Poster IIIb

BP 21.3: Poster

Wednesday, March 20, 2024, 11:00–14:30, Poster C

Implementation and Implications of a Lattice Model for the Understanding of Lipid Rafts in Membranes — •Simon Kellers, Fabian Keller, and Andreas Heuer — Institute of Physical Chemistry, University of Münster, Corrensstrasse 28/30, 48149 Münster, Germany

Based on comprehensive and extensive MD simulations of lipid bilayers, consisting of unsaturated, saturated lipids and CHOL [1], an existing lattice model [2][3] has been extended to incorporate the effects of CHOL on lipid ordering, relevant for the formation of lipid rafts. The MD simulation results suggest that interactions strongly depend on local CHOL concentrations. Furthermore, both lipids and CHOL are surrounded by four neighbors each, implying a square lattice model with a subgrid for CHOL.

The model relies solely on the enthalpic data from simulations and requires no phenomenological input. Additionally, as key variable it takes the order parameter of the lipids into account. The entropic contributions of the individual chains are adjusted through an iterative Boltzmann procedure, allowing for a clear separation and investigation of enthalpic and entropic effects. Due to the coarse-grained nature of the model, extensive and prolonged simulations of large systems will be feasible, allowing for the investigation of, e.g., the emergence of phase separation or phase transitions. [1] Keller, F; Heuer, A; Soft Matter 2021, 25, 17 [2] Hakobyan, D; Heuer, A; J. Chem. Phys. 2017, 6, 142 [3] Hakobyan, D; Heuer, A; J. Chem. Theory Comput. 2019, 11, 15

Keywords: Lipid bilayers; Lattice model; Cholesterol