1. The Binding of Aβ42 Peptide Monomers to Sphingomyelin/Cholesterol/Ganglioside Bilayers Assayed by Density Gradient Ultracentrifugation
- Author
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Hasna Ahyayauch, Igor de la Arada, Massimo E. Masserini, José L. R. Arrondo, Félix M. Goñi, and Alicia Alonso
- Subjects
aβ42 ,beta-amyloid ,membrane binding ,density gradient ultracentrifugation ,ganglioside ,sphingomyelin ,cholesterol ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
The binding of Aβ42 peptide monomers to sphingomyelin/cholesterol (1:1 mol ratio) bilayers containing 5 mol% gangliosides (either GM1, or GT1b, or a mixture of brain gangliosides) has been assayed by density gradient ultracentrifugation. This procedure provides a direct method for measuring vesicle-bound peptides after non-bound fraction separation. This centrifugation technique has rarely been used in this context previously. The results show that gangliosides increase by about two-fold the amount of Aβ42 bound to sphingomyelin/cholesterol vesicles. Complementary studies of the same systems using thioflavin T fluorescence, Langmuir monolayers or infrared spectroscopy confirm the ganglioside-dependent increased binding. Furthermore these studies reveal that gangliosides facilitate the aggregation of Aβ42 giving rise to more extended β-sheets. Thus, gangliosides have both a quantitative and a qualitative effect on the binding of Aβ42 to sphingomyelin/cholesterol bilayers.
- Published
- 2020
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