title: Effects of unsaturated fatty acids and triacylglycerols on phosphatidylethanolamine membrane structure.
abstract: Lipid intake in diet regulates the membrane lipid composition, which in turn controls activities of membrane proteins. There is evidence that fatty acids (FAs) and triacylglycerols (TGs) can alter the phospholipid (PL) mesomorphism. However, the molecular mechanisms involved are not fully understood. This study focuses on the effect of the unsaturation degree of the C-18 FAs, oleic acid (OA), linoleic acid and linolenic acid, and their TGs, triolein (TO), trilinolein, and trilinolenin, on the structural properties of phosphoethanolamine PLs. By means of X-ray diffraction and 31P-NMR spectroscopy, it is shown that both types of molecules stabilize the HII phase in 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE) liposomes. Several structural factors are considered to explain the correlation between the FA unsaturation degree and the onset temperature of the HII phase. It is proposed that TGs could act as lateral spacers between polar DEPE groups, providing an increase in the effective surface area per lipid molecule that would account for the structural parameters of the HII phase. Fluorescence polarization data indicated a fluidification effect of OA on the lamellar phase. TO increased the viscosity of the hydrophobic core with a high effect on the HII phase.
authors.affiliation: Molecular and Cellular Biomedicine, Institut Universitari d'Investigacions en Ciencies de la Salut, Associate Unit of Instituto de la Grasa (CSIC), Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Prades
authors.forename: Sérgio S
authors.initials: SS
authors.lastname: Funari
authors.forename: Pablo V
authors.initials: PV
authors.lastname: Escribá
authors.forename: Francisca
authors.initials: F
authors.lastname: Barceló
mesh_terms: D002462:Cell Membrane / Q000737:chemistry; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D005454:Fluorescence Polarization; D057927:Hydrophobic and Hydrophilic Interactions; D008081:Liposomes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013696:Temperature; D014280:Triglycerides / Q000378:metabolism*; D014783:Viscosity; D014961:X-Ray Diffraction
chemical_list: D005231:Fatty Acids, Unsaturated; D008081:Liposomes; D010714:Phosphatidylethanolamines; D014280:Triglycerides; C483858:phosphatidylethanolamine