title: Cholesterol-phospholipid complexation in fluid bilayers as evidenced by nearest-neighbor recognition measurements.
abstract: Nearest-neighbor recognition experiments have been carried out using varying ratios of exchangeable dimer analogs of 1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol and 1,2-distearoyl-sn-glycero-3-phosphatidylglycerol in cholesterol-rich unilamellar vesicles at 60 degrees C. Equilibrium dimer distributions that were obtained support a structural model of the liquid-ordered bilayer in which free cholesterol and the longer-chain phospholipid homodimer are in equilibrium with a complex of unique stoichiometry, where one cholesterol molecule combines with two of the long-chain phospholipid homodimers. In this model, the mixing of the short-chain phospholipids with the uncomplexed long-chain phospholipids is ideal, and the complexed dimers are shielded from the disulfide exchange reaction.
authors.affiliation: Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
authors.forename: Jianbing
authors.initials: J
authors.lastname: Zhang
authors.forename: Honghua
authors.initials: H
authors.lastname: Cao
authors.forename: Steven L
authors.initials: SL
authors.lastname: Regen
mesh_terms: D002627:Chemistry, Physical / Q000379:methods*; D002784:Cholesterol / Q000737:chemistry*; D019281:Dimerization; D004220:Disulfides / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry; D008560:Membrane Fluidity; D008956:Models, Chemical; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D013107:Sphingolipids / Q000737:chemistry; D013696:Temperature
chemical_list: D004220:Disulfides; D008051:Lipid Bilayers; D008055:Lipids; D008081:Liposomes; D010713:Phosphatidylcholines; D010743:Phospholipids; D013107:Sphingolipids; D002784:Cholesterol