Fluorescence study of the effect of cholesterol on spectrin–aminophospholipid interactions

摘要: The ability of the membrane skeletal protein spectrin to interact with phospholipids, and aminophospholipids in particular, both natural model membranes, is well documented. present study involves phospholipid-induced quenching tryptophan fluorescence probe spectrin–membrane interactions presence absence cholesterol. We performed experiments on small unilamellar vesicles phospholipids made DMPC DMPC/DMPE DOPC DOPC/DOPE without cholesterol at two different temperatures, one below 15 °C another above, 50 °C, main phase transition temperature (T m) bulk phospholipid. Results indicate that erythroid brain binds membranes by tenfold 40-fold stronger, respectively, 20 % cholesterol, up which gel (Lβ) liquid crystalline (Lα) phases coexists, particularly DMPC-based containing saturated fatty acyl chains not DOPC-based appreciably lower T m. Time-resolved circular dichroism spectroscopic studies indicated no significant change mean lifetime residues secondary structures proteins upon binding phospholipid SUVs.