Monoacylglycerols alter the lipid composition and molecular mobility of phosphatidylcholine bilayers: 13C NMR evidence of dynamic lipid remodeling

Elizabeth Boyle, Donald M. Small, Donald Gantz, James A. Hamilton, J. Bruce German

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Abstract

The physical effects of monoacylglycerols (MAG) in small unilamellar vesicles composed of phosphatidylcholine (PC), triolein, cholesterol, and varying amounts of monopalmitin and monoolein were studied by 13C-NMR. The signal to noise ratio of the carbonyls of PC and triolein were enhanced by the addition of 1,2-di-[1-13C]palmitoylphosphatidylcholine and tri-[1-13C]oleoylglycerol. The linewidths of the carbonyl- 13C, choline methyl, olefinic carbon, and terminal methyl resonances were measured digitally from vesicles with 0 to 42 mol % of MAG. Significant increases in the linewidth of carbonyl (P < 0.05), olefinic and terminal methyl carbons (P < 0.01) of vesicles containing 42 mol % monopalmitin indicated that these groups experienced restricted molecular mobility at high monopalmitin concentrations. However, more striking was the apparent displacement of triolein from the surface environment of PC bilayers to an oil-like environment in systems containing only 8 mol % monopalmitin. Displacement of triolein from the surface by monoolein occurred only above 15 mol %. Thus, saturated and monounsaturated monoacylglycerols, natural products of lipoprotein metabolism, dynamically alter both the lipid composition and molecular mobility of lipoprotein surfaces in distinct ways.

Original languageEnglish (US)
Pages (from-to)764-772
Number of pages9
JournalJournal of Lipid Research
Volume37
Issue number4
StatePublished - Apr 1996

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Keywords

  • C NMR
  • Lipoprotein lipase
  • Monoolein
  • Monopalmitin
  • Remnant uptake

ASJC Scopus subject areas

  • Endocrinology

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