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Quantitative and Qualitative Method for Sphingomyelin by LC-MS Using Two Stable Isotopically Labeled Sphingomyelin Species
Published on: May 7, 2018
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Phase behavior of palmitoyl and egg sphingomyelin
Zoran Arsov1, Emilio J González-Ramírez2, Felix M Goñi2
1Department of Condensed Matter Physics, Laboratory of Biophysics, Jozef Stefan Institute, 1000 Ljubljana, Slovenia.
Chemistry and Physics of Lipids
|April 25, 2018
Summary
This study reveals distinct phase behaviors for palmitoyl sphingomyelin (PSM) and egg sphingomyelin (ESM) bilayers. Oriented lipid films provide detailed structural insights into sphingomyelin phases, clarifying their complex temperature-dependent properties.
Area of Science:
- Lipid Bilayer Structure and Dynamics
- Biophysical Chemistry
- Materials Science
Background:
- Sphingomyelins (SMs) are crucial biological lipids with limited structural data compared to glycerophospholipids.
- Existing literature shows confusion regarding the phase behavior of SM bilayers.
- Understanding SM phase transitions is vital for cell membrane studies.
Purpose of the Study:
- To investigate the temperature-dependent phase behavior of palmitoyl sphingomyelin (PSM) and egg sphingomyelin (ESM) bilayers.
- To characterize the structural properties of different SM phases (gel, ripple, fluid).
- To assess the utility of oriented lipid films for studying SM phase transitions.
Main Methods:
- X-ray diffraction and X-ray diffuse scattering on hydrated, oriented thick bilayer stacks.
- Temperature control from 3°C to 55°C.
- Wide-angle X-ray scattering for chain tilt and area/lipid determination.
Main Results:
- Egg sphingomyelin (ESM) exhibits a stable ripple phase from 3°C to ~38°C.
- Palmitoyl sphingomyelin (PSM) shows a gel phase at 3°C, transitioning to ripple at ~24°C and fluid at ~41°C.
- Calculated area/lipid in the fluid phase (~64 Ų) is larger than previously reported.
Conclusions:
- Oriented lipid films are highly effective for resolving and characterizing SM ripple phases.
- PSM and ESM display unique phase behaviors and transition temperatures.
- The study provides precise structural data for SM phases, resolving literature discrepancies.
Keywords:
Fluid phaseGel phaseRipple phaseRipple wavelengthVolume determinationX-ray diffractionX-ray diffuse scatteringMore Related Videos
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