title: Monolayer spontaneous curvature of raft-forming membrane lipids.
abstract: Monolayer spontaneous curvatures for cholesterol, DOPE, POPE, DOPC, DPPC, DSPC, POPC, SOPC, and egg sphingomyelin were obtained using small-angle X-ray scattering (SAXS) on inverted hexagonal phases (HII). Spontaneous curvatures of bilayer forming lipids were estimated by adding controlled amounts to a HIIforming template following previously established protocols. Spontaneous curvatures of both phosphatidylethanolamines and cholesterol were found to be at least a factor of two more negative than those of phosphatidylcholines, whoseJ0values are closer to zero. Interestingly, a significant positiveJ0value was retrieved for DPPC. We further determined the temperature dependence of the spontaneous curvaturesJ0(T) in the range from 15 to 55 °C, resulting in a quite narrow distribution of -1 to -3 × 10-3(nm °C)-1for most investigated lipids. The data allowed us to estimate the monolayer spontaneous curvatures of ternary lipid mixtures showing liquid ordered/liquid disordered phase coexistence. We report spontaneous curvature phase diagrams for DSPC/DOPC/Chol, DPPC/DOPC/Chol and SM/POPC/Chol and discuss effects on protein insertion and line tension.
authors.affiliation: Institute of Molecular Biosciences, Biophysics Division, University of Graz, Austria. Georg.Pabst@uni-graz.at ; ; Tel: +43 316 4120-342.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Kollmitzer
authors.affiliation: Institute of Molecular Biosciences, Biophysics Division, University of Graz, Austria. Georg.Pabst@uni-graz.at ; ; Tel: +43 316 4120-342.
authors.forename: Peter
authors.initials: P
authors.lastname: Heftberger
authors.affiliation: Institute of Inorganic Chemistry, Graz University of Technology, Austria ; School of Food Science and Nutrition, University of Leeds, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Rappolt
authors.affiliation: Institute of Molecular Biosciences, Biophysics Division, University of Graz, Austria. Georg.Pabst@uni-graz.at ; ; Tel: +43 316 4120-342.
authors.forename: Georg
authors.initials: G
authors.lastname: Pabst