Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.23.216341v1?rss=1 Authors: Alavizargar, A., Keller, F., Heuer, A. Abstract: Cholesterol and ergosterol are two dominant sterols in the membranes of eukaryotic and yeast cells, respectively. Although their chemical structure is very similar, their impact on the structure and dynamics of membranes differs.In this work, we have explored the effect of these two sterols on binary mixtures with 1,2-dipalnitoyl-sn-glycerol-3-phosphocholine (DPPC) lipid bilayer at various sterol concentration and temperatures, employing molecular dynamics simulations. The simulations revealed that cholesterol has a stronger impact on the ordering of the lipid chains and leads to more condensed membranes with respect to ergosterol. This difference likely arises from a more planar structure of the ring part as well as the better alignment of cholesterol among the DPPC chains with respect to ergosterol. The degree of the planarity of the ring system affects the orientation of the methyl groups on the rough side and distribute the lipid chains on the two sides of the sterols differently. Similar to the structural observations, cholesterol also has a stronger influence on the dynamics, and consistently, establishes stronger DPPC-sterol interactions when compared to ergosterol. Although our findings are consistent with some previous simulations as well as recent experiments, they are at odds with some other studies. Therefore, the presented results may shed new lights on the impact of sterols on the saturated lipids bilayers with implications for binary mixtures of lipids as well as lipid rafts. Copy rights belong to original authors. Visit the link for more info