| Project/Area Number |
11440206
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
機能・物性・材料
|
|---|
| Research Institution | The University of Tokushima |
|---|
Principal Investigator |
KANESHINA Shoji The University of Tokushima, Faculty of Engineering, Professor, 工学部, 教授 (80035617)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
VILLENEUVE Masumi Saitama University, Faculty of Science, Instructor, 理学部, 助手 (30304554)
MATSUKI Hitoshi The University of Tokushima, Faculty of Engineering, Associate Professor, 工学部, 助教授 (40229448)
|
|---|
| Project Period (FY) |
1999 – 2002
|
| Keywords | phospholipids / bilayers / phase transition / high pressure / biomembranes / liquid crystalline phase / gel phase / interdigitated gel phase |
|---|
| Research Abstract |
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
|
