Berlin 2018 – scientific programme

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BP: Fachverband Biologische Physik

BP 16: Membranes and Vesicles I (joint session BP/CPP)

BP 16.11: Talk

Wednesday, March 14, 2018, 12:30–12:45, H 1028

Membrane curvature and nanobuds generated by lipids with bulky head groups — Aparna Sreekumari, Reinhard Lipowsky, and •Rikhia Ghosh — Theory and Bio-systems, Max Planck Institute of Colloids and Interfaces Golm, D-14424 Potsdam, Germany

We study the mechanical and curvature-elastic properties of bilayer membranes with compositional asymmetry by molecular simulations. The compositional asymmetry is achieved by inserting lipids with a bulky head group into one leaflet (or monolayer) of the bilayer. As we increase the mole fraction φ₁ of the bulky-head lipids, we observe a remarkable evolution of the stress profile across the bilayer and a strong increase in the first moment of this profile. In order to extract the spontaneous curvature from this moment, we also determine the bending rigidity of the bilayer which is found to exhibit a non-monotonic dependence on φ₁. The latter behaviour reflects changes in the mean density of the lipid tails and head groups. The resulting spontaneous curvature is found to be quite large compared to other molecular mechanisms for bilayer asymmetry. The generated curvature leads to the formation of nanobuds, which provide new membrane compartments, in close analogy to cellular budding processes.