Beijing National Laboratory for Molecular Sciences, Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Phys Chem B. 2022 Jul 28;126(29):5481-5489. doi: 10.1021/acs.jpcb.2c03127. Epub 2022 Jul 15.
This work investigates the interactions in cholesterol and sphingomyelin monolayers at the molecular level by high-resolution broadband sum frequency generation vibrational spectroscopy (HR-BB-SFG-VS). The SFG spectra of natural egg sphingomyelin (ESM) as a function of cholesterol concentration are obtained at an air/water interface under different polarization combinations. The analysis of the spectra shows that cholesterol can induce sphingomyelin conformational changes at an air/water interface. The mechanism is proposed. When cholesterol is inserted into the ESM monolayer, the inherent intramolecular hydrogen bonds between the phosphate moiety and 3OH in the sphingosine backbones are destroyed. During this process, the sphingosine backbones become more ordered, while the conformation of the N-linked long acid chain remains unaltered. The OH of the cholesterol head group can bind to the -PO of the ESM molecule, and the orientation of the -PO in the head groups changes to be more parallel to the interface.
本工作通过高分辨率宽带和频振动光谱（HR-BB-SFG-VS）研究了胆固醇和神经鞘磷脂单层在分子水平上的相互作用。在不同的偏振组合下，在空气/水界面获得了天然鸡蛋神经鞘磷脂（ESM）的胆固醇浓度的 SFG 光谱。光谱分析表明，胆固醇可以诱导空气/水界面上的神经鞘磷脂构象变化。提出了这种机制。当胆固醇插入 ESM 单层时，磷酸部分和鞘氨醇骨架中 3OH 之间的固有分子内氢键被破坏。在此过程中，鞘氨醇骨架变得更加有序，而 N 连接的长酸链的构象保持不变。胆固醇头部基团的 OH 可以与 ESM 分子的-PO 结合，并且头部基团中-PO 的取向变为更平行于界面。
