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Hexagonal phase with ordered acyl chains formed by a short chain asymmetric ceramide
F G Dupuy1, S P Fernández Bordín2, B Maggio3
1Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, T4000ILI San Miguel de Tucumán, Argentina.
Colloids and Surfaces. B, Biointerfaces
|October 14, 2016
Summary
Short-chain ceramides form a novel, highly ordered inverted hexagonal phase in lipid membranes. This unique structure, driven by molecular asymmetry, offers new insights into lipid behavior and membrane organization.
Area of Science:
- Lipid Biophysics
- Membrane Science
- Materials Science
Background:
- Ceramides are lipids known for high melting points and promoting negative membrane curvature.
- Short-chain ceramides, like C10:0 ceramide, possess molecular asymmetry due to distinct sphingosine and acyl chain lengths.
Purpose of the Study:
- To investigate the phase behavior and structural organization of short-chain C10:0 ceramide in hydrated lipid dispersions.
- To characterize the acyl chain order within any observed lipid phases.
Main Methods:
- High-sensitivity differential scanning calorimetry (DSC) for thermal transitions.
- Small-angle X-ray scattering (SAXS) and polarized light microscopy for structural analysis.
- Infrared spectroscopy and wide-angle X-ray diffraction (WAXD) for acyl chain order determination.
Main Results:
- C10:0 ceramide exhibits a minor exothermic peak at 61°C and a main endothermic transition at 75°C.
- Below 75°C, hydrated dispersions form a three-dimensional inverted hexagonal phase.
- Acyl chains within this hexagonal phase display a notably high degree of order, a novel observation for lipid hexagonal phases.
Conclusions:
- The molecular asymmetry of C10:0 ceramide is proposed as the driving force behind the formation of this unique, highly ordered inverted hexagonal phase.
- This finding represents the first report of a lipid hexagonal phase with highly ordered acyl chains.
- The study provides novel insights into ceramide self-assembly and membrane structural possibilities.
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