Detection of Sphingomyelin Clusters by Raman Spectroscopy.
Sphingomyelin (SM) is a major sphingolipid in mammalian cells that forms specific lipid domains in combination with cholesterol (Chol). Using molecular-dynamics simulation and density functional theory calculation, we identified a characteristic Raman band of SM at ∼1643 cm(-1) as amide I of the SM cluster. Experimental results indicate that this band is sensitive to the hydration of SM and the presence of Chol. We showed that this amide I Raman band can be utilized to examine the membrane distribution of SM. Similarly to SM, ceramide phosphoethanolamine (CerPE) exhibited an amide I Raman band in almost the same region, although CerPE lacks three methyl groups in the phosphocholine moiety of SM. In contrast to SM, the amide I band of CerPE was not affected by Chol, suggesting the importance of the methyl groups of SM in the SM-Chol interaction.
Lipid Biology Laboratory, RIKEN, Saitama, Japan.
Koichiro
K
Shirota
Theoretical Molecular Science Laboratory, RIKEN, Saitama, Japan.
Kiyoshi
K
Yagi
Lipid Biology Laboratory, RIKEN, Saitama, Japan.
Takehiko
T
Inaba
Theoretical Molecular Science Laboratory, RIKEN, Saitama, Japan.
Pai-Chi
PC
Li
Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan; Lipid Active Structure Project, Japan Science and Technology Agency, ERATO, Osaka, Japan.
Michio
M
Murata
Theoretical Molecular Science Laboratory, RIKEN, Saitama, Japan.
Yuji
Y
Sugita
Lipid Biology Laboratory, RIKEN, Saitama, Japan; UMR 7213 CNRS, University of Strasbourg, Illkirch, France. Electronic address: kobayasi@riken.jp.
Toshihide
T
Kobayashi
D000818:Animals; D002645:Chickens; D002784:Cholesterol / Q000737:chemistry; D004531:Eggs; D006860:Hydrogen Bonding; D008051:Lipid Bilayers / Q000737:chemistry; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D013059:Spectrum Analysis, Raman; D013109:Sphingomyelins / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D008051:Lipid Bilayers; D013109:Sphingomyelins; D014867:Water; C060281:ceramide phosphoethanolamine; D002784:Cholesterol