The effect of pressure on vesicle fusion

✍ Scribed by E.L. Chang

• Publisher: Elsevier Science
• Year: 1986
• Weight: 352 KB
• Volume: 139-140
• Category: Article
• ISSN: 0378-4363
• DOI: 10.1016/0378-4363(86)90721-7

✦ Synopsis

We have attempted to examine the possible role of non-bilayer structures, such as the inverted hexagonal phase (Hn), in vesicle fusion by using pressure as a probe. The role of non-bilayer phases in biological functions has elicited much interest. The present evidence depends mainly on electron microscopy and 3~p NMR studies. Our work with pressure on unsaturated phosphatidylethanolamines shows that the H[t phase is destabilized by pressure in that the lamellar-to-hexagonal transition temperature (T L -.) is shifted up in temperature with increasing pressure. The TL_ H transition temperature is very sensitive to applied pressure, 47°C/kbar being about twice the value for chain melting transitions. If the fusion of vesicles depends on the transient existence of the H. phase or similar non-bilayer structures, then pressure should also inhibit the extent of fusion. We are presently examining the pressure dependence of the fusion of vesicles that are composed of lipids with a L-H a transition at 40-50°C. Preliminary results show that pressure inhibits fusion of these vesicles.