Dynamical Behaviors of Amphiphilic Molecules in Biological Membranes and Model Membranes As Studied by Deuterium Nuclear Magnetic Resonance

在这个项目中，我们尝试使用氘核磁共振数据对各向异性环境中受约束的分子链进行构象分析。该项目的范围可以分为两个主要部分：溶解在向列相溶剂中的柔性链的构象分析和聚集在向列相溶剂中的两亲性分子的构象分析。在RIS近似的框架下，分析了一系列n-C2Dlt；2n+2&gt；(n=5，6，7，8，10和16)正己烷的质子-质子偶极耦合和重水核磁共振四极裂解的实验值。结果表明，正构烷烃链在向列相介质中表现出高度的各向异性。将处理扩展到溶解在液晶中的氧乙烯链CH3[OCH2CH2]xOCH3(x=1，2，3)。发现氧化乙烯链通过选择性地增强反式…来应对各向异性环境较多的C-C键(S)。辛酸钠(C_8Na)-1-癸醇(C_&lt；10&gt；OH)-水三元体系的相变行为已被广泛研究。这是因为它表现出各种液晶相。我们分析了在六方相(E)、薄层相(D)和反六方相(F)中观察到的C_8Na和C_&lt；10&gt；OH分子的四极分裂数据。得到了以下结果：C_8Na分子。C-C键的反式分数(F_T)从头基到甲基端有逐渐减小的趋势。在E相中，C_8Na分子具有第二键的柔韧性，而在D和F相中，C_8Na分子中的键比较刚性。在D阶段，第二个键实际上是固定在高契态。下一个C-C键也显示出明显的Guche构象偏好。相反，其他键的ft值相对较大。然后，从头基到甲基端的距离几乎等于伸展形式的C_8Na分子的距离。这表明薄片具有平坦的表面。另一方面，在E和F阶段，所有的C-C键都倾向于处于反式状态。E相和F相之间的ft值差异只存在于第八键。在E相中，当C_8Na浓度较高时，C_&lt；10&gt；OH链的甲基端容易移动，而在F相中则受到限制。较少

In this project, we have attempted to perform the conformational analyses of molecular chains constrained in anisotropic environments, using the deuterium NMR data. The scope of this project may be divided into two main parts : the conformational analysis of flexible chains dissolved in nematic solvents and that of amphiphilic molecules incorporated in their aggregates.Conformational anisotropy of n-alkane chains in nematic environment has been investigated. Experimental values of proton-proton dipolar couplings of n-hexane and deuterium NMR quardrupolar splittings of a series of n-C_2D_<2n+2> (n=5, 6, 7, 8, 10, and 16) were analyzed within the framework of the RIS approximation. As a result, n-alkane chains were shown to be highly anisotropic in the nematic media. The treatment was extended to oxyethylene chains CH_3[OCH_2CH_2]_xOCH_3 (x=1, 2, and 3) dissolved in a liquid crystal. Oxyethylene chains were found to cope with the anisotropic environment by selectively enhancing the trans … More fraction of the C-C bond (s).The phase transitional behavior of a ternary system of sodium octanoate (C_8Na) - 1-decanol (C_<10>OH) - water has been extensively studied. This is because it exhibits a variety of liquid crystalline phases. We have analyzed the deuterium NMR quadrupolar splitting data observed for C_8Na and C_<10>OH molecules in the hexagonal (E), lambellar (D), and reversed hexagonal (F) phases. The following results were obtained.C_8Na molecule. The trans fraction (f_t) of the C-C bonds tends to decrease gradually from the head group to the methyl end. The flexibility of the second bond from the polar head is characteristic of the C_8Na molecule in the E phase, while in the D and F phases the bond is rather rigid.C_<10>OH molecule. In the D phase, the second bond is virtually fixed in the gauche state. The next C-C bond also shows a marked preference for the gauche conformation. In contrast, the f_t values of the other bonds are comparatively large. Then the distance from the head group to the methyl end is nearly equal to that of the C_8Na molecule in its stretched form. This suggests that the lamellae have flat surfaces. On the other hand, in the E and F phases, all the C-C bonds prefer to be in the trans state. The difference in the f_t value between the E and F phases can be found only in the eighth bond. In the E phase were the C_8Na concentration is high, the methyl end of the C_<10>OH chain is easy to move, whereas it is constrained in the F phase. Less