Citra M J, Axelsen P H
Department of Pharmacology, Johnson Research Foundation for Molecular Biophysics, University of Pennsylvania, Philadelphia, 19104-6084 USA.
Biophys J. 1996 Oct;71(4):1796-805. doi: 10.1016/S0006-3495(96)79380-3.
When polarized internal reflection infrared spectroscopy is used to determine molecular order in supported lipid membranes, the results are critically dependent on the accuracy of assumptions made about the evanescent electric field amplitudes in the membrane. In this work, we examine several expressions used for calculating evanescent electric field amplitudes in supported lipid monolayers and bilayers, and test their validity by measuring the infrared dichroism of poly-gamma-benzyl-L-glutamate and poly-beta-benzyl-L-aspartate under conditions in which their molecular order is known. Our results indicate that treating such systems as a simple single interface between two semi-infinite bulk phases is more accurate than the commonly employed thin-film approximation. This implies that earlier conclusions about molecular order in supported lipid membranes may require substantial revision.
当使用偏振内反射红外光谱法来测定支撑脂质膜中的分子有序性时，结果严重依赖于对膜中倏逝电场振幅所做假设的准确性。在这项工作中，我们研究了用于计算支撑脂质单层和双层中倏逝电场振幅的几种表达式，并通过在已知其分子有序性的条件下测量聚-γ-苄基-L-谷氨酸酯和聚-β-苄基-L-天冬氨酸的红外二色性来测试它们的有效性。我们的结果表明，将此类系统视为两个半无限体相之间的简单单界面比常用的薄膜近似更为准确。这意味着关于支撑脂质膜中分子有序性的早期结论可能需要大幅修正。
