Distortion of the lamellar arrangement of phospholipids by deep rough mutant lipopolysaccharide from Salmonella minnesota
| Autor: | Béla Kocsis, Attila Bóta, Edit Urbán, K. Lohner |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Small-angle X-ray scattering
Vesicle technology industry and agriculture Phospholipid Analytical chemistry Biological membrane Condensed Matter Physics chemistry.chemical_compound Crystallography chemistry Lamellar phase Dipalmitoylphosphatidylcholine Phosphatidylcholine lipids (amino acids peptides and proteins) Lamellar structure Physical and Theoretical Chemistry |
| Zdroj: | Journal of Thermal Analysis and Calorimetry. 82:463-469 |
| ISSN: | 1572-8943 1388-6150 |
| DOI: | 10.1007/s10973-005-0918-9 |
| Popis: | The concentration dependent effects of deep rough mutant lipopolysaccharide (LPS) from Salmonella minnesota (R595) on two different phospholipid model membranes was investigated by differential scanning calorimetry and small-angle X-ray scattering (SAXS). At low concentrations of LPS the well ordered multilamellar arrangement of dipalmitoylphosphatidylcholine (DPPC) vesicles is strongly distorted resulting in a loss of positional correlation of the lipid lamellae and smaller domain sizes within the lamellae. The pre-transition of DPPC was abolished at a LPS/DPPC molar ratio of 0.1:1 and the main or chain melting transition was strongly broadened. Moreover, the enthalpy was significantly decreased and a transition was hardly detected at an equimolar mixture of LPS/DPPC. LPS also affected the lamellar arrangement of a mixture of dipalmitoylphosphatidylethanolamine (DPPE) and dipalmitoylphosphatidylglycerol (DPPG). Furthermore, a phase separation was observed for this phospholipid mixture resulting in DPPE enriched and depleted domains. Similarly to DPPC, only a weak phase transition was observed at the highest LPS concentration used (LPS/DPPE-DPPG 1:1 mol/mol). SAXS measurements showed that for both systems increasing the concentration of LPS resulted in a concomitant increase of the formation of cubic structures, which are predominant at an equimolar mixture of LPS/phospholipid. However, because of the small number of peaks it was not possible to unambiguously identify the space group of the cubic structure, complicated by the coexistence with a lamellar phase, which was particularly detectable for the LPS/DPPC mixture. |
| Databáze: | OpenAIRE |
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