Levin I W, Thompson T E, Barenholz Y, Huang C
Biochemistry. 1985 Oct 22;24(22):6282-6. doi: 10.1021/bi00343a036.
Vibrational Raman spectroscopic experiments have been performed as a function of temperature on aqueous dispersions of synthetic DL-erythro-N-lignoceroylsphingosylphosphocholine [C(24):SPM], a racemic mixture of two highly asymmetric hydrocarbon chain length sphingomyelins. Raman spectral peak-height intensity ratios of vibrational transitions in the C-H stretching-mode region show that the C(24):SPM-H2O system undergoes two thermal phase transitions centered at 48.5 and 54.5 degrees C. Vibrational data for fully hydrated C(24):SPM are compared to those of highly asymmetric phosphatidylcholine dispersions. The Raman data are consistent with the plausible model that the lower temperature transition can be ascribed to the conversion of a mixed interdigitated gel state (gel II) to a partially interdigitated gel state (gel I) and that the higher temperature transition corresponds to a gel I----liquid-crystalline phase transition. The observation of a mixed interdigitated gel state (gel II) at temperatures below 48.5 degrees C implies that biological membranes may have lipid domains in which some of the lipid hydrocarbon chains penetrate completely across the entire hydrocarbon width of the lipid bilayer.
已针对温度开展了振动拉曼光谱实验，实验对象是合成的DL-赤型-N-木蜡酰鞘氨醇磷酸胆碱[C(24):SPM]的水分散体，C(24):SPM是两种高度不对称的烃链长度鞘磷脂的外消旋混合物。在C-H伸缩模式区域中，振动跃迁的拉曼光谱峰高强度比表明，C(24):SPM-H₂O系统经历了两个热相变，相变温度分别为48.5和54.5摄氏度。将完全水合的C(24):SPM的振动数据与高度不对称的磷脂酰胆碱分散体的数据进行了比较。拉曼数据与一个合理模型相符，即较低温度的相变可归因于混合交叉排列凝胶态（凝胶II）向部分交叉排列凝胶态（凝胶I）的转变，而较高温度的相变则对应于凝胶I向液晶相的转变。在低于48.5摄氏度的温度下观察到混合交叉排列凝胶态（凝胶II），这意味着生物膜可能具有脂质结构域，其中一些脂质烃链完全穿透脂质双层的整个烃宽度。
