The Long-Chain Sphingoid Base of Ceramides Determines Their Propensity for Lateral Segregation
| Autor: | Tomokazu Yasuda, J. Peter Slotte, Michio Murata, Md. Abdullah Al Sazzad |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Ceramide Membranes 030102 biochemistry & molecular biology Sphingosine Parinaric Acid Stereochemistry Bilayer Biophysics Base analog Ceramides 03 medical and health sciences chemistry.chemical_compound 030104 developmental biology chemistry Phase (matter) Phosphatidylcholines Proton NMR lipids (amino acids peptides and proteins) POPC |
| Zdroj: | Biophysical Journal. 112:976-983 |
| ISSN: | 0006-3495 |
| Popis: | We examined how the length of the long-chain base or the N -linked acyl chain of ceramides affected their lateral segregation in 1-palmitoyl-2-oleoyl- sn -glycero-3-phosphocholine (POPC) bilayers. Lateral segregation and ceramide-rich phase formation was ascertained by a lifetime analysis of trans -parinaric acid (tPA) fluorescence. The longer the length of the long-chain base (d16:1, d17:1, d18:1, d19:1, and d20:1 in N -palmitoyl ceramide), the less ceramide was needed for the onset of lateral segregation and ceramide-rich phase formation. A similar but much weaker trend was observed when sphingosine (d18:1)-based ceramide had N -linked acyl chains of increasing length (14:0 and 16:0–20:0 in one-carbon increments). The apparent lateral packing of the ceramide-rich phase, as determined from the longest-lifetime component of tPA fluorescence, also correlated strongly with the long-chain base length, but not as strongly with the N -acyl chain length. Finally, we compared two ceramide analogs with equal carbon numbers (d16:1/17:0 or d20:1/13:0) and observed that the analog with a longer sphingoid base segregated at lower bilayer concentrations to a ceramide-rich phase compared with the shorter sphingoid base analog. The gel phase formed by d20:1/13:0 ceramide also was more thermostable than the gel phase formed by d16:1/17:0 ceramide. 2 H NMR data for 10 mol % stearoyl ceramide in POPC also showed that the long-chain base was more ordered than the acyl chain at comparable chain positions and temperatures. We conclude that the long-chain base length of ceramide is more important than the acyl chain length in determining the lateral segregation of the ceramide-rich gel phase and intermolecular interactions therein. |
| Databáze: | OpenAIRE |
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