title: Monolayer membranes and bilayer vesicles characterized by alpha- and beta-anomer of sulfoquinovosyldiacyglycerol (SQDG).
abstract: Physicochemical properties of 1,2-di-O-stearoyl-3-O-(6-deoxy-6-sulfo-alpha-D-glucopyranosyl)-sn-glycerol (alpha-SQDG-C(18:0)) and 1,2-di-O-stearoyl-3-O-(6-deoxy-6-sulfo-beta-D-glucopyranosyl)-sn-glycerol (beta-SQDG-C(18:0)) in monolayer and bilayer membranes were examined. Surface pressure measurements in monolayer membranes indicated the molecular area of beta-SQDG-C(18:0) to be slightly smaller than that of alpha-SQDG-C(18:0). In bilayer membranes, the phase transition temperature and the enthalpy of beta-SQDG-C(18:0) were higher than those of alpha-SQDG-C(18:0), while the trapping efficiency of beta-SQDG-C(18:0) vesicles was lower. The results suggested tighter packing with beta-SQDG-C(18:0) than alpha-SQDG-C(18:0), due to differences in the head group stereochemistry. High-performance liquid chromatography-electrospray ionization ion trap mass spectrometry (HPLC-ESI-MS) data and computational modeling studies provided supporting evidence for morphological differences. In both monolayer and bilayer membranes, the affinity of beta-SQDG-C(18:0) with cholesterol was greater than that of alpha-SQDG-C(18:0), again due to the differences in head group properties. Turbidity measurement and microscopic examination of alpha- and beta-SQDG-C(18:0)/cholesterol mixtures confirmed formation of large vesicles. The addition of cholesterol to SQDG-C(18:0) optimized membrane formation and stabilized its structure.
authors.affiliation: Department of Applied Biological Science, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba-ken 278-8510, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Hideki
authors.initials: H
authors.lastname: Sakai
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ohta
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kameda
authors.forename: Fumio
authors.initials: F
authors.lastname: Sugawara
authors.forename: Masahiko
authors.initials: M
authors.lastname: Abe
authors.forename: Kengo
authors.initials: K
authors.lastname: Sakaguchi
mesh_terms: D002152:Calorimetry, Differential Scanning; D002784:Cholesterol / Q000737:chemistry*; D006017:Glycolipids / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D008968:Molecular Conformation; D009391:Nephelometry and Turbidimetry; D044367:Phase Transition; D021241:Spectrometry, Mass, Electrospray Ionization; D013499:Surface Properties; D013696:Temperature
chemical_list: D006017:Glycolipids; D008051:Lipid Bilayers; D008081:Liposomes; C013694:sulfoquinovosyl diglyceride; D002784:Cholesterol