pH-Dependent physicochemical properties of ornithine lipid in mono- and bilayers

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...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2022-09, Vol.24 (37), p.22778-22791
Main Authors: Mukhina, Tetiana, Pabst, Georg, Ruysschaert, Jean-Marie, Brezesinski, Gerald, Schneck, Emanuel
Format: Article
Language:English
Subjects:
Bacteria
Chains
Hydrogen bonding
Lipids
Membranes
Superlattices
X-ray fluorescence
X-ray scattering
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Summary: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. Ornithine lipid has a greater tendency than DMPE to form ordered structures and a molecular superlattice based on a hydrogen bonding network between the headgroups.
ISSN:1463-9076
1463-9084
DOI:10.1039/d2cp01045c