Interaction of spermine with polyphosphoinositides containing liposomes and myo-inositol 1,4,5 triphosphate.

The interaction of spermine with liposomes containing 2% phosphatidylinositol, phosphatidylinositol 4 phosphate and phosphatidylinositol 4,5 biphosphate was inferred from the ability of these liposomes to interfere with spermine binding to the resin heparin-Sepharose. The inositol phospholipids tested showed different affinities for spermine: the order of binding strength appear to be phosphatidylinositol phosphatidylinositol 4 phosphate phosphatidylinositol 4,5 biphosphate. The ability of vesicles containing 2% polyphosphoinositides to interact with spermine is comparable to that of either single stranded RNAs or highly negatively charged liposomes. Myo-inositol 1,4,5 triphosphate has a much lower ability to bind spermine.