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Updated: Aug 28, 2025

Assembly of Cell Mimicking Supported and Suspended Lipid Bilayer Models for the Study of Molecular Interactions
Published on: August 3, 2021
pH-Dependent physicochemical properties of ornithine lipid in mono- and bilayers
Tetiana Mukhina1, Georg Pabst2, Jean-Marie Ruysschaert3
1Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrase 8, 64289 Darmstadt, Germany. emanuel.schneck@pkm.tu-darmstadt.de.
Abstract:
In certain bacteria, phosphatidylethanolamine lipids (PEL) get largely replaced by phosphate-free ornithine lipids (OL) under conditions of phosphate starvation. It has so far been unknown how much these two lipid types deviate in their physicochemical properties, and how strongly bacteria thus have to adapt in order to compensate for the difference. Here, we use differential scanning calorimetry, X-ray scattering, and X-ray fluorescence to investigate the properties of OL with saturated C14 alkyl chains in mono- and bilayers. OL is found to have a greater tendency than chain-analogous PEL to form ordered structures and, in contrast to PEL, even a molecular superlattice based on a hydrogen bonding network between the headgroups. This superlattice is virtually electrically uncharged and persists over a wide pH range. Our results indicate that OL and PEL behave very differently in ordered single-component membranes but may behave more similarly in fluid multicomponent membranes.
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