Abstract
In the concentration range of 10-5 to 10-1 M Ca2+ modulates the thermotropic properties of several neutral and anionic glycosphingolipids (galactosylceramide, asialo-GM1, sulfatide, GM1, GD1a, GT1b) and of their mixtures with dipalmitoylphosphatidylcholine. The transition temperature of gangliosides is not appreciably changed while the transition enthalpy increases by 20% in the presence of Ca2+. The more marked effect of Ca2+ is on the thermotropic behavior of systems containing sulfatide. Increasing concentrations of Ca2+ between 10-5 and 10-3 M (up to a molar ratio of Ca2+/sulfatide 1:2) induce a progressive increase of both the transition temperature and enthalpy. Further increases up to 10-1 M Ca2+ induce a new phase transition at a lower temperature. No evidence is found for induction of phase separation of pure glycosphingolipid-Ca2+ domains in mixtures of any of the glycosphingolipids with dipalmitoylphosphatidylcholine. The modification of the phase behavior of anionic glycosphingolipids by Ca2+ does not involve detectable variations of the intermolecular packing but is accompanied by marked modifications of the dipolar properties of the polar head group region.
Original language | English (US) |
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Pages (from-to) | 173-182 |
Number of pages | 10 |
Journal | BBA - Biomembranes |
Volume | 901 |
Issue number | 2 |
DOIs | |
State | Published - Jul 23 1987 |
Externally published | Yes |
Keywords
- Calcium ion modulation
- Galactocerebroside
- Ganglioside
- Glycosphingolipid
- Phase transition
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Cell Biology