Tuning membrane domain structure and surface charge through the interplay of lipid composition, ions, and the charge state of ganglioside GM1
Year: 2026
Type: article
Abstract: Gangliosides contribute to membrane organization and are key components of functional membrane domains. Among them, GM1 is particularly relevant because of its preferential association with cholesterol-rich ordered domains and its involvement in membrane-mediated recognition processes. Yet, how its structural and electrostatic properties depend on the local lipid and ionic environment remains poorly understood. Here, we combine grazing-incidence X-ray scattering (GIXS), grazing-incidence X-ray diffraction (GIXD), and total-reflection X-ray fluorescence (TRXF) to investigate GM1-containing lipid monolayers with different phospholipid matrices with or without cholesterol. We show that membrane composition strongly determines the structural response to the ionic environment: cholesterol stabilizes a liquid-ordered state with comparatively weak structural sensitivity to calcium, whereas GM1 and millimolar concentrations of Ca 2 + promote denser packing in cholesterol-free lipid mixtures and shift the phase behavior toward ordered states. Importantly, quantification of interfacial ion adsorption reveals that GM1 deprotonation and the resulting membrane charge are coupled to molecular packing. These results establish membrane organization and interfacial charge regulation as mutually coupled properties, controlled by the interplay between lipid composition, ion accumulation, and the charge state of GM1, with potential implications for molecular interactions at biomembrane surfaces.
Institutions: Technische Universität Darmstadt, University of Milan
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $4,470
OpenAlex ID: W7223238118