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。这个项目的范围可以分为两个主要部分：在向列溶剂中溶解的柔性链的构象分析和在其聚集体中结合的两亲分子的构象分析。研究了正构烷烃链在向列环境下的构象各向异性。在RIS近似的框架内分析了n- c_2d_ <2n+2> （n=5、6、7、8、10和16）系列的质子-质子偶极耦合和氘核磁共振四极分裂的实验值。结果表明，正构烷烃链在向列介质中具有高度的各向异性。将处理扩展到氧乙烯链CH_3[OCH_2CH_2]_xOCH_3 （x= 1,2,3）溶解在液晶中。氧乙烯链通过选择性地增强反式和C-C键(s)的更多部分来应对各向异性环境。对辛酸钠(C_8Na) - 1-癸醇(C_<10>OH) -水三元体系的相变行为进行了广泛研究。这是因为它表现出多种液晶相。我们分析了C_8Na和C_<10>OH分子在六方(E)、层状(D)和反六方(F)相的氘核磁共振四极分裂数据。实验结果如下：c_8na分子。C-C键的反式分数（f_t）从头基到甲基端逐渐减小。从极头开始的第二个键的柔韧性是E相的C_8Na分子的特征，而在D和F相的键是相当刚性的。在D相中，第二个键实际上固定在间扭式结构中。下一个碳碳键也明显倾向于间扭式构象。相比之下，其他键的f_t值相对较大。那么从头基到甲基端的距离几乎等于伸展后的C_8Na分子的距离。这表明片层表面是平坦的。另一方面，在E相和F相中，所有的碳碳键都倾向于处于反式态。E相和F相的f_t值只有在第8个键上才有差异。在C_8Na浓度较高的E相中，C_<10>OH链的甲基端易于移动，而在F相中则受到限制。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