Cholesterol-induced alterations of the packing properties of gangliosides: an EPR study.
The effect of cholesterol (Chol) on two kinds of glycolipid assemblies, one composed of monosialogangliosides (GM1a) and the other formed by a natural mixture of bovine brain gangliosides (TBG), has been analysed. The experimental approach involves spin label electron paramagnetic resonance (EPR) in aqueous lipid dispersions. The employment of a hydrosoluble spin label and a 'quencher' of the EPR signal that is not able to permeate lipid interfaces, allowed us to conclude that GM1a/Chol mixtures give rise to vesicles at Chol proportions for which TBG/Chol mixtures form micelles. The use of different liposoluble spin labels reveals that cholesterol produces a straightening of the hydrocarbon chains in both lipid systems. In GM1a/Chol mixtures, this feature is more pronounced and it is coupled with a decrease in polarity at the chain ends.
Pincelli
M M
MM
Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, Argentina.
Levstein
P R
PR
Fidelio
G D
GD
Gennaro
A M
AM
D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D002784:Cholesterol / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D005677:G(M1) Ganglioside / Q000737:chemistry; D005732:Gangliosides / Q000737:chemistry* / Q000302:isolation & purification; D008958:Models, Molecular; D008962:Models, Theoretical; D008968:Molecular Conformation
D005732:Gangliosides; D005677:G(M1) Ganglioside; D002784:Cholesterol