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BP: Fachverband Biologische Physik

BP 8: Poster Session Ia

BP 8.15: Poster

Monday, March 18, 2024, 18:00–20:30, Poster C

Structure and Electrostatics in Monolayers of Raft-Forming Lipid Mixtures Containing GM1 — •Miriam Grava¹, Valeria Rondelli², and Emanuel Schneck¹ — ¹Technische Universität Darmstadt, Germany — ²Università degli Studi di Milano, Italy

Lipid rafts are membrane domains with specific lipid composition and high sterol content, that can host certain membrane protein. Important examples are lipid domains enriched in glycosphingolipids such as ganglioside GM1 with negatively chargeable sialic acids, whose protonation state can depend on lipid packing and on the type and concentration of counterions.

Here, we use mixed lipid monolayers to mimic GM1-containing rafts in the mammalian nervous system and investigate them with synchrotron-based x-ray scattering and x-ray fluorescence, to elucidate their structural and electrostatic characteristics under various biologically relevant conditions.

The experiments reveal electron density profiles, in-plane lipid ordering, and the surface charge density. The absence of a pronounced charge inversion in the presence of divalen cations indicates that a considerable fraction of ions bridges two negatively charged GM1 molecules.

Keywords: GM1 ganglioside; Lipid monolayer; X-ray Scattering; X-ray fluorescence; X-ray diffraction