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

氘核磁共振研究生物膜和模型膜中两亲分子的动力学行为

基本信息

批准号：
02650642
负责人：
SASANUMA Yuji
金额：
$ 1.02万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

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

在本计画中，我们尝试利用氘核磁共振资料，对各向异性环境中的分子链进行构象分析。本课题的研究内容主要包括两个方面：一是柔性链在水溶液中的构象分析，二是两亲分子在水溶液中的构象分析，研究了正构烷烃链在水溶液中的构象各向异性。在RIS近似下，分析了正己烷的质子-质子偶极耦合和一系列n-C_2D_<2n+2>（n=5，6，7，8，10和16）的氘核磁共振四极分裂的实验值。结果表明，正构烷烃链在水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杂环链CH_3[OCH_2CH_2]_xOCH_3（x=1，2，3）。Oxygen链被发现通过选择性地增强反式结构来科普各向异性环境。 ...更多信息本文研究了辛酸钠（C_8Na）-癸醇（C_ OH）-水三元体系的相转变行为<10>。这是因为它表现出多种液晶相。本文分析了C_8Na和C_<10>OH分子在六方相（E）、Lambellar相（D）和反六方相（F）中的氘核磁共振四极分裂数据。结果表明：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。在E相中，C_8Na分子的极性头第二键是柔性的，而在D和F相中，C_8Na分子的极性头第二键是刚性的<10>。在D阶段，第二个键实际上固定在gauche状态。下一个C-C键也显示出明显的偏侧构象偏好。相比之下，其它键的f_t值相对较大。从头基到甲基端的距离几乎等于伸展态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相中，所有的C-C键都倾向于处于反式状态。E相和F相的f_t值仅在第8个键处有差别。在E相中，C_8Na浓度高时，C_ OH链的甲基端<10>容易移动，而在F相中，C_8Na浓度高时，C_ OH链的甲基端受到限制。少