CHOLESTEROL-INDUCED STABILIZATION OF LAMELLAR STRUCTURES IN GANGLIOSIDE-CONTAINING LIPID AGGREGATES - A P-31-NMR STUDY

Self-assembled structures of phosphatidylcholine (PC), gangliosides an d cholesterol (CHOL) have been studied by pulsed phosphorus-31 nuclear magnetic resonance (P-31-NMR). The incorporation of gangliosides to m ultilamellar vesicles of PC destabilizes the structure leading to the formation of micelles and small aggregates. At intermediate gangliosid e/phospholipid molar ratios, besides the well-characterized signals fr om lamellar structures and small aggregates, a signal that we assigned to cylindrical micelles is observed. Upon addition of CHOL, an increa se of the bilayer signal at the expense of that assigned to the cylind rical micellar structures, indicates that the destabilization process is reverted. This effect is consistent with the reduction of the exper imental molecular area found in mixed ganglioside/CHOL monolayers as c ompared with the ideal non-interacting case. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.