Composition and structure of lipopolysaccharide-human plasma low density lipoprotein complex. Analytical ultracentrifugation,31P-NMR, ESR and fluorescence spectroscopy studies
| Autor: | Elena M. Gladkaya, Vasily A. Yurkiv, N.V. Medvedeva, Vladimir A. Kosykh, Andrei D. Morozkin, Eugeny A. Podrez, Alexander V. Victorov |
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| Rok vydání: | 1989 |
| Předmět: |
Lipopolysaccharides
chemistry.chemical_classification Magnetic Resonance Spectroscopy Apolipoprotein B biology Electron Spin Resonance Spectroscopy Biophysics Fluorescence spectrometry Phospholipid Fatty acid Cell Biology Oligosaccharide Biochemistry Lipoproteins LDL chemistry.chemical_compound Spectrometry Fluorescence chemistry Phosphatidylcholine biology.protein Humans lipids (amino acids peptides and proteins) Ultracentrifuge Ultracentrifugation Lipoprotein |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 984:119-127 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/0005-2736(89)90351-9 |
| Popis: | Complexes of Salmonella typhimurium lipopolysaccharide toxin (LPS) with low density lipoproteins (LDL) prepared in vitro have been analyzed. LPS-LDL complexes were found to comprise approx. 0.24 mg LPS/mg LDL protein. The major protein of complexes was apolipoprotein apoB-100 (greater than or equal to 90-95%). Incorporation of LPS molecules into LDL was accompanied by small changes in lipid composition, i.e. the phosphatidylcholine content was diminished by approx. 11% and the free fatty acid concentration was raised 2-fold. Analytical ultracentrifugation showed that insertion of LPS into LDL results in the increase of a portion of particles with higher density (lower flotation coefficient) compared to initial LDL. As was evidenced by ESR, in LPS-LDL complexes, the phospholipid hydrocarbon chains are more ordered than in LDL. 31P-NMR spectra indicated that in LPS-LDL complexes the mobility of phospholipid polar headgroups is restricted in comparison with LDL. Application of the shift reagent (Pr3+) revealed that phospholipid molecules form a monolayer structure on the surface of complexes. Upon binding of LPS to LDL, a maximum of the apoB intrinsic fluorescence was slightly red-shifted (1-2 nm) which may testify that the localization of apoB remains nearly unchanged. For LPS-LDL complexes, the accessibility of apoB fluorophores to quenchers (I-, Cs+, acrylamide) did not dramatically differ from that of LDL. It is concluded that rather large amounts of LPS (about 9-10 molecules) can accommodate in one LDL particle without severely perturbing its original composition and structure. Moreover, in the LPS-LDL complexes, oligosaccharide chains of LPS screen notably neither phospholipid polar headgroups nor, what is very important, apoB. LPS-LDL complexes are suggested to be able in vivo to bind to cellular apoB/E receptors, possible LPS receptors and scavenger-receptors of macrophages (monocytes). |
| Databáze: | OpenAIRE |
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