In Situ PM-IRRAS Studies of an Archaea Analogue Thiolipid Assembled on a Au(111) Electrode Surface
In Situ PM-IRRAS Studies of an Archaea Analogue Thiolipid Assembled on a Au(111) Electrode Surface
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DOI：
10.1021/la900907d
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发表时间：
2009-09-01
期刊：
影响因子：
3.9
通讯作者：
Lipkowski, Jacek
中科院分区：
文献类型：
--
作者：
Leitch, Jay;Kunze, Julia;Lipkowski, Jacek
用偏振调制红外反射吸收光谱(PM-IRRAS)研究了2，3-二-O-植酸基-sn-甘油-1-四甘醇-DL-α-硫辛酸酯(DPTL)在金电极表面自组装的单分子膜的构象、取向和水化行为。这种古生代类似物硫脂最近已被用来构建系留类脂双层。通过合成DPTdt6L，这是一种带有氘取代的四甘醇间隔基的DPTL分子，可以区分植酸链和四甘醇间隔基的C-H伸缩振动，并分别获得链、间隔基和硫辛酸头基的特征红外光谱。结果表明，单分子膜的结构在较宽的电极电位范围内表现出显着的稳定性，植酸基链处于液晶状态。四甘醇链是卷曲的，红外光谱表明该区域处于无序状态。这项研究最重要的结果是，与预期相反的是，间隔区的水合作用很差。我们的研究结果对基于该硫脂的系留类脂膜的设计具有一定的指导意义。
Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) has been applied to determine the conformation, orientation, and hydration of a monolayer of 2,3-di-O-phytanyl-sn-glycerol-1-tetraethylene glycol-DL-alpha-lipoic acid ester (DPTL) self-assembled at a gold electrode surface. This Archaea analogue thiolipid has been recently employed to build tethered lipid bilayers. By synthesizing DPTdt6L, a DPTL molecule with a deuterium substituted tetraethylene glycol spacer, it was possible to differentiate the C-H stretch vibrations of the phytanyl chains from the tetraethylene glycol spacer and acquire the characteristic IR spectra for the chains, spacer, and lipoic acid headgroup separately. Our results show that the structure of the monolayer displays remarkable stability in a broad range of electrode potentials and that the phytanyl chains remain in a liquid crystalline state. The tetraethylene glycol chains are coiled, and the IR spectrum for this region shows that it is in the disordered state. The most significant result of this study is the information that in contrast to expectations the spacer region is poorly hydrated. Our results have implications for the design of a tethered lipid membrane based on this thiolipid.