P-31 NUCLEAR-MAGNETIC-RESONANCE IN MEMBRANE-FUSION STUDIES

Membrane fusion study has resulted, in part, from the development of technologies for studying various aspects of the membrane fusion events and the development of models for fusion mechanisms that is tested by using the new technologies. Two of the most significant fusion mechanisms that are proposed are based on model membrane fusion studies of simple lipid vesicles. One of the models utilizes a mechanism involving calcium and phosphatidylserine (or cardiolipin), which may involve a gel (dehydrated) phase formation by the calcium–phosphatidylserine complex. The second pathway involves isotropic structures, Is, identified in 31P nuclear magnetic resonance spectra of lipid dispersions as intermediates in membrane fusion. The isotropic structures satisfy the fundamental demands of fusion mechanisms. There are various steps for fusion—aggregation or adhesion of the membranes that will fuse and destabilization of the bilayer at the point of fusion. The chapter describes the available techniques for detecting nonbilayer structures. © 1993, Elsevier Inc. All rights reserved.