Dresden 2020 – scientific programme

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BP: Fachverband Biologische Physik

BP 9: Poster II

BP 9.27: Poster

Monday, March 16, 2020, 17:30–19:30, P2/2OG

Comparison of Cholesterol and Ergosterol in Binary Bilayer Membranes: Insights from Molecular Dynamics Simulations — •Azadeh Alavizargar, Fabian Keller, Marc Lütgehermöller, and Andreas Heuer — University of Muenster

Cholesterol and Ergosterol are two dominant sterols in the membrane of eukaryotic cells and yeast cells, respectively. Although their chemical structure is very similar, with the exception of two extra double bonds and one methyl group for Ergosterol, their impact on the structure and dynamics of membranes differs. In this work, we have explored different points in the binary phase diagram of the mixtures of these sterols molecules with 1,2-Dipalnitoyl-sn- glycerol-3-phosphocholine (DPPC) lipid bilayer system, employing molecular dynamics simulations. The simulations revealed that Cholesterol has a stronger impact on ordering of the lipids chains with respect to Ergosterol, which likely arise from a more planar structure of the ring part as well as lower tilt angle of this sterol with respect to Ergosterol. Both sterols slightly decrease the order parameter of the pure bilayer system in gel phase and considerably increase it in liquid- ordered phase. From the dynamics point of view, addition of the two sterols leads to faster dynamics of lipids in gel phase with the opposite effect above phase transition temperature. Furthermore, Cholesterol apparently has a stronger influence on the dynamics than Ergosterol in accordance with available experimental data. These results may shed new lights on the impact of sterols on the binary mixtures of membranes.