Effect of Hydrostatic Pressure on Self-Organization of Lipid Molecules

静水压力对脂质分子自组织的影响

基本信息

批准号：
11440206
负责人：
KANESHINA Shoji
金额：
$ 9.02万
依托单位：
The University of Tokushima
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

项目摘要

In order to understand the effect of hydrostatic pressure on self-organization of lipid molecules, the thermotropic and barotropic phase transitions of phospholipid bilayer membranes were observed by high-pressure optical method and differential scanning calorimetry. Present results are as follows.1. The bilayer phase transitions of a series of 1,2-diacylphosphatidylcholines containing linear saturated acyl chain(12-18 carbon number) were observed under high pressure. The temperature of main transition for each lipid was elevated almost linearly by pressure. The slope of temperature-pressure diagram was in the range of 0.20-0.23 KMPa^<-1> depending on the acyl chain-length.2. The temperature of the pretransition from the lamellar gel phase to the ripple gel phase was also elevated by pressure. The value of dT/dP was in the range of 0.12-0.14 KMPa^<-1>3. Pressure-induced interdigitated gel phase was observed beyond 300MPa for 14:0-PC, 175MPa for 15:0-PC, 100MPa for 16:0-PC, 80MPa for 17 … More :0-PC and 7OMPa for 18:0-PC, respectively.4. The temperature pressure phase diagrams of ether-linked phosphatidylcholine (PC) bilayer membranes were compared with those of ester-linked PC bilayer membranes. The most surprisingly difference between ether- and ester-linked PC lies in the pretransition. The ether-linked PC bilayer membrane undergoes thermotropic pretransition between the interdigitated gel and lamellar gel phases.5. Effect of unsaturated acyl chains on the phase transitions of lipid bilayer membranes was studied. The temperatures of the main transition between the liquid crystal and the lamellar gel phase were almost linearly elevated by pressure. The values of dT/dP for unsaturated lipid were smaller than that for the saturated lipid. The substitution of cis unsaturated chain for saturated chains of distearoyl-PC brought about the depression of transition temperature by 48±1℃ for every chain.6. Effect of head groups on the bilayer phase transitions of phospholipids was studied. The main transition temperature for dipalmitoylphospatidylethanolamine (DPPE) and N-methylated DPPE were determined under high pressure. The main transition temperatures of N-methylated DPPEs increased linearly by applying pressure while they decreased with increasing the size of head group by stepwise N-methylation. Less

为了了解静水压对脂质分子自组织的影响，采用高压光学方法和差示扫描量热法观察了磷脂双层膜的热致性和正压性相变。目前的研究结果如下： 1．在高压下观察了一系列含有线性饱和酰基链（12-18个碳数）的1,2-二酰基磷脂酰胆碱的相变。每种脂质的主要转变温度。温度-压力图的斜率随酰基链长度的变化几乎呈线性升高。2．层状凝胶相预转变的温度。波纹凝胶相也因压力而升高。dT/dP的值在0.12-0.14KMPa^-1>3范围内。观察到的凝胶相分别超过 300MPa（14:0-PC）、175MPa（15:0-PC）、100MPa（16:0-PC）、80MPa（17 … More:0-PC）和 7OMPa（18:0-PC）。 4醚联磷脂酰胆碱 (PC) 双层膜的温度压力相图与酯连接的PC 双层膜。醚连接的PC 与酯连接的PC 之间最令人惊奇的区别在于预转变。醚连接的PC 双层膜在交指凝胶和层状凝胶相之间发生热致预转变。5．对脂质双层膜的相变进行了研究，液晶相和层状凝胶相之间的主要转变温度几乎随压力呈线性升高。不饱和脂质的dT/dP小于饱和脂质，顺式不饱和链取代二硬脂酰-PC的饱和链，导致各链的转变温度降低48±1℃。 6．研究了二棕榈酰磷脂酰乙醇胺(DPPE)和N-甲基化DPPE在高压下的主要转变温度。 N-甲基化 DPPE 通过施加压力而线性增加，而通过逐步 N-甲基化，N-甲基化 DPPE 随着头基大小的增加而减少。