Effect of Salmonella minnesota R595 LPS on the dipalmitoylphosphatidyl-ethanolamine (DPPE)-dipalmitoylglycerol (DPG)-water model membrane system

Edit Urbán, Attila Bóta, Béla Kocsis

Research output: Contribution to journalArticle


The effect of Salmonella minnesota R595 lipopolysaccharide (LPS) on model membrane consisting of a mixture of fully hydrated lipids (dipalmitoylphosphatidylethanolamine (DPPE) and dipalmitoylglycerol (DPG)) was investigated by differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS) and freeze-fracture methods. The DPPE-DPG/water system forms a multilamellar arrangement in the gel phase which transforms into a mixture of inverted hexagonal and cubic structures. By the presence of LPS the thermotropic behaviour of the system was affected significantly only at its high concentration (1:1 mol/mol LPS/DPPE-DPG) in the gel phase, while above the chain melting transition the ratio of the inverted cubic and the hexagonal structures was changed and at the 1:1 mol/mol LPS/DPPE-DPG ratio a complex and amorphous phase was formed. The structural parameters of the inverted hexagonal and cubic phases are modified by the temperature and also by the LPS concentration, as deduced from the characteristic SAXS curves. Summarizing the effects of the LPS molecules on the DPPE-DPG/water vesicle system a schematic phase diagram was constructed.

Original languageEnglish
Pages (from-to)28-35
Number of pages8
JournalChemistry and Physics of Lipids
Issue number1-2
Publication statusPublished - Apr 1 2006



  • DPPE-DPG vesicles
  • DSC
  • Freeze-fracture
  • Lipopolysaccharide
  • Non-bilayer phases
  • SAXS

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Organic Chemistry
  • Cell Biology

Cite this