Mushayakarara E, Albon N, Levin I W
Biochim Biophys Acta. 1982 Apr 7;686(2):153-9. doi: 10.1016/0005-2736(82)90107-9.
The Raman spectra of 1,2-dipalmitoylphosphatidylcholine (DPPC) dihydrate crystals were examined in (a) the 1250 and 1080 cm-1 PO-2 antisymmetric and symmetric stretching mode regions, (b) the 1730 cm-1 carbonyl stretching mode region and (c) the 2800-3100 cm-1 C-H stretching mode interval. No evidence was observed for hydrogen bonding effects involving the nonester phosphate oxygen atoms. Spectra of the DPPC dihydrate crystal in the 1250 cm-1 region are compared to spectra of both anhydrous and successively hydrated systems and to spectra of crystalline glycerylphosphorylcholine. The splitting pattern in the 1240 to 1280 cm-1 interval for the DPPC dihydrate was interpreted in terms of the different bonding arrangements assumed by the PO-2 groups in the two molecule asymmetric unit of the eight molecule unit cell. An unusual triplet is observed in the carbonyl stretching mode region around 1730 cm-1. These features reflect differing bond environments, relative to the polar and hydrophobic regions of the bilayer, of the 1- and 2-chain carbonyl groups. Spectra for crystalline DPPC dihydrate in the 3000 cm-1 C-H stretching mode region suggest a hybrid chain packing lattice which is analogous to the packing arrangement determined for the isostructurally similar DMPC dihydrate species.
对二水合1,2 - 二棕榈酰磷脂酰胆碱（DPPC）晶体的拉曼光谱进行了研究，研究范围包括：（a）1250和1080厘米⁻¹处的PO₂不对称和对称伸缩模式区域；（b）1730厘米⁻¹处的羰基伸缩模式区域；以及（c）2800 - 3100厘米⁻¹处的C - H伸缩模式区间。未观察到涉及非酯磷酸氧原子的氢键效应。将1250厘米⁻¹区域的二水合DPPC晶体光谱与无水及连续水合体系的光谱以及结晶甘油磷酸胆碱的光谱进行了比较。根据八个分子晶胞的两个分子不对称单元中PO₂基团所假定的不同键合排列，对二水合DPPC在1240至1280厘米⁻¹区间的分裂模式进行了解释。在1730厘米⁻¹左右的羰基伸缩模式区域观察到一个不寻常的三重峰。这些特征反映了相对于双层的极性和疏水区域，1 - 链和2 - 链羰基的不同键环境。3000厘米⁻¹ C - H伸缩模式区域的结晶二水合DPPC光谱表明存在一种混合链堆积晶格，这类似于对结构相似的二水合DMPC所确定的堆积排列。
