Charged Membrane Surfaces Impede the Protein-Mediated Transfer of Glycosphingolipids between Phospholipid Bilayers

摘要: A lipid transfer protein that facilitates the of glycolipids between donor and acceptor membranes has been investigated using a fluorescence resonance energy assay. The glycolipid (23-24 kDa, pI 9.0) catalyzes high specificity lipids have sugars beta-linked to either ceramide or diacylglycerol backbone, such as simple gangliosides, but not phospholipids, cholesterol, cholesterol esters. In this study, we examined effect different charged on rate anthrylvinyl-labeled galactosylceramide (1 mol %) from vesicle population at neutral pH. Compared membranes, introduction negatively 5 10 % into vesicles significantly decreased rate. Introduction same amount negative charge membrane did impede effectively. Also, positive in was effective slowing vesicle. Increasing ionic strength buffer with NaCl reversed effects. At pH, (pI congruent is expected be positively charged, which may promote association membrane. Based these other experiments, conclude process follows first-order kinetics off-rate surface rate-limiting step process.