Cooperative Hydrogen-Bond Dynamics at a Zwitterionic Lipid/Water Interface Revealed by 2D HD-VSFG Spectroscopy
Cooperative Hydrogen-Bond Dynamics at a Zwitterionic Lipid/Water Interface Revealed by 2D HD-VSFG Spectroscopy
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DOI：
10.1021/acs.jpclett.7b02057
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发表时间：
2017-10-19
影响因子：
5.7
通讯作者：
Tahara, Tahei
中科院分区：
文献类型：
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作者：
Inoue, Ken-ichi;Singh, Prashant C.;Tahara, Tahei
在分子水平上阐明生物膜界面水合作用对于理解生物过程具有重要意义。我们利用二维外差检测振动和频率产生（2D HD-VSFG）光谱研究了两性离子磷脂酰胆碱/水界面的超快氢键动力学。得到的二维光谱证实，阴离子磷酸和阳离子胆碱在界面处分别水合。此外，数据表明，水在两性离子脂质界面上的动力学不是简单的水水合物成单独的磷酸盐和胆碱的动力学总和。二维光谱的中心线斜率（CLS）分析表明，在两性离子脂质界面处，磷酸盐周围的超快氢键波动没有明显抑制，这使得氢键动力学看起来与体水相似。本研究表明，膜界面上的氢键动力学不仅取决于界面上特定位置的氢键，而且在很大程度上取决于附近和其他附近部分的水动力学，通过氢键网络。
Molecular-level elucidation of hydration at biological membrane interfaces is of great importance for understanding biological processes. We studied ultrafast hydrogen-bond dynamics at a zwitterionic phosphatidylcholine/water interface by two-dimensional heterodyne-detected vibrational sum frequency generation (2D HD-VSFG) spectroscopy. The obtained 2D spectra confirm that the anionic phosphate and cationic choline sites are individually hydrated at the interface. Furthermore, the data show that the dynamics of water at the zwitterionic lipid interface is not a simple sum of the dynamics of the water species that hydrate to the separate phosphate and choline. The center line slope (CLS) analysis of the 2D spectra reveals that ultrafast hydrogen bond fluctuation is not significantly suppressed around the phosphate at the zwitterionic lipid interface, which makes the hydrogen-bond dynamics look similar to that of the bulk water. The present study indicates that the hydrogen-bond dynamics at membrane interfaces is not determined only by the hydrogen bond to a specific site of the interface but is largely dependent on the water dynamics in the vicinity and other nearby moieties, through the hydrogen-bond network.