We studied the effect of gangliosides GD1a and GM1 on the lamellar-to- hexagonal II phase transition of mixtures of dioleoylphosphatidylethanolamine/dioleoylphosphatidylcholine, 3:1, and of transphosphatidylated phosphatidylethanolamine with dioleoylglycerol by high- sensitivity differential scanning calorimetry, 31P-NMR, and pyrene fluorescence of a phosphatidylcholine probe. Gangliosides had a dual effect. Below 1 mol% ganglioside the hexagonal II phase transition was affected but still occurred at lower temperature than in the absence of gangliosides. The presence of between 1 and 2 mol % gangliosides increased the temperature for formation of the hexagonal II phase and progressively decreased its cooperativity. Above 3 mol % gangliosides totally inhibited the formation of both the temperature-induced and composition-induced hexagonal phase, probably by opposing the geometric distortions necessary for the inverted micellar structures.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Oct 11 1994|
- pyrene fluorescence
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