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Quantitative determination of ion distributions in bacterial lipopolysaccharide membranes by grazing-incidence X-ray fluorescence

A model of the outer membrane of Gram-negative bacteria was created by the deposition of a monolayer of purified rough mutant lipopolysaccharides at an air/water interface. The density profiles of monovalent (K+) and divalent (Ca2+) cations normal to the lipopolysaccharides (LPS) monolayers were inv...

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Bibliographic Details
Main Authors: Schneck, Emanuel (Author) , Schubert, Thomas (Author) , Konovalov, Oleg V. (Author) , Quinn, Bonnie E. (Author) , Gutsmann, Thomas (Author) , Brandenburg, Klaus (Author) , Oliveira, Rafael G. (Author) , Pink, David A. (Author) , Tanaka, Motomu (Author)
Format: Article (Journal)
Language:English
Published: May 4, 2010
In: Proceedings of the National Academy of Sciences of the United States of America
Year: 2010, Volume: 107, Issue: 20, Pages: 9147-9151
ISSN:1091-6490
DOI:10.1073/pnas.0913737107
Online Access:Resolving-System, lizenzpflichtig, Volltext: https://doi.org/10.1073/pnas.0913737107
Verlag, lizenzpflichtig, Volltext: https://www.pnas.org/doi/full/10.1073/pnas.0913737107
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Author Notes:Emanuel Schneck, Thomas Schubert, Oleg V. Konovalov, Bonnie E. Quinn, Thomas Gutsmann, Klaus Brandenburg, Rafael G. Oliveira, David A. Pink, and Motomu Tanaka
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Summary:A model of the outer membrane of Gram-negative bacteria was created by the deposition of a monolayer of purified rough mutant lipopolysaccharides at an air/water interface. The density profiles of monovalent (K+) and divalent (Ca2+) cations normal to the lipopolysaccharides (LPS) monolayers were investigated using grazing-incidence X-ray fluorescence. In the absence of Ca2+, a K+ concentration peak was found in the negatively charged LPS headgroup region. With the addition of CaCl2, Ca2+ ions almost completely displaced K+ ions from the headgroup region. By integrating the experimentally reconstructed excess ion density profiles, we obtained an accurate measurement of the effective charge density of LPS monolayers. The experimental findings were compared to the results of Monte Carlo simulations based on a coarse-grained minimal model of LPS molecules and showed excellent agreement.
Item Description:Gesehen am 20.06.2023
Physical Description:Online Resource
ISSN:1091-6490
DOI:10.1073/pnas.0913737107

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