Structural preferences of phosphatidylinositol and phosphatidylinositol-phosphatidylethanolamine model membranes influence of Ca2+ and Mg2+ |
| |
Authors: | R Nayar SL Schmid MJ Hope PR Cullis |
| |
Institution: | Biochemistry Department, The University of British Columbia, Vancouver, B.C. V6T 1W5 Canada |
| |
Abstract: | The structural preferences of soya phosphatidylinositol in isolation and in mixtures with soya phosphatidylethanolamine, and the influence of Ca2+ and Mg2+ on these preferences, have been examined employing 31P-NMR and freeze-fracture techniques. It is shown that phosphatidylinositol assumes the bilayer organization on hydration both in the presence and absence of Ca2+ and Mg2+. In mixed systems with HII phase) phosphatidylethanolamine, phosphatidylinositol induces lipidic particle structure at low (<10 mol%) concentrations and bilayer structure at higher levels. In systems containing 15 or 20 mol% phosphatidylinositol, Ca2+ (but not Mg2+) can induce HII phase structure. The results indicate that phosphatidylinositol is a more effective agent than other acidic phospholipids for stabilizing bilayer structure, particularly when high levels of divalent cations are present. These findings are discussed in terms of functional roles of phosphatidylinositol and mechanisms whereby Ca2+ induces structural reorganization in mixed systems containing acidic phospholipids and phosphatidylethanolamine. |
| |
Keywords: | Phosphatidylinositol Phospholipid structure Model membrane Freeze-fracture |
本文献已被 ScienceDirect 等数据库收录! |