title: Raman spectroscopy for detecting supported planar lipid bilayers composed of ganglioside-GM1/sphingomyelin/cholesterol in the presence of amyloid-β.
abstract: The aggregation and fibril formation of amyloid β(Aβ) peptides onto a ganglioside-GM1-containing lipid membrane is a cause of neurodegenerative diseases. The mechanism of the initial binding and the conformational changes of Aβ on the membrane should be clarified. Fluorescence microscopy and Raman spectroscopy have been performed to investigate the supporting planar lipid bilayers (SPBs) composed of ganglioside-GM1, sphingomyelin and cholesterol. It is demonstrated that the SPBs are in a liquid-crystalline state when placed on mica, and increasing the amount of ganglioside-GM1 can decrease the lateral interaction between the acyl chains of the SPBs. It has been found that Aβ(1-40) initially interacts with the galactose ring of the ganglioside-GM1 head group, leading to its binding and gradual aggregation on the membrane surface. The obvious change observed in Raman spectroscopy in the ν(C-H) region confirms that the hydrophobic C-terminal of Aβ(1-40) inserts itself into the hydrophobic part of the SPBs. The Raman data indicate that α-helix and β-sheet structures of Aβ(1-40) increase and coexist over longer time frames. Based on these results, a model was proposed to describe the mechanism of the conformational changes and the aggregation of Aβ(1-40) that are mediated by ganglioside-GM1-containing SPBs.
authors.affiliation: School of Physics and Electronics, Henan University, Kaifeng 475004, China. ylmao@henu.edu.cn.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Hu
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wang
authors.forename: Weirong
authors.initials: W
authors.lastname: Wang
authors.forename: Zhenlong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Huiping
authors.initials: H
authors.lastname: Gao
authors.forename: Yanli
authors.initials: Y
authors.lastname: Mao
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry*; D005677:G(M1) Ganglioside / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013109:Sphingomyelins / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000538:Aluminum Silicates; D016229:Amyloid beta-Peptides; D008051:Lipid Bilayers; D010446:Peptide Fragments; D013109:Sphingomyelins; C078592:amyloid beta-protein (1-40); D005677:G(M1) Ganglioside; D002784:Cholesterol; C011934:mica