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Gel Phase Membrane Retards Amyloid β-Peptide (1–42) Fibrillation by Restricting Slaved Diffusion of Peptides on Lipid Bilayers

Author:
Yang, Mengting, Wang, Kang, Lin, Jiake, Wang, Liqun, Wei, Feng, Zhu, Jintao, Zheng, Wanquan, Shen, Lei
Source:
Langmuir 2018 v.34 no.28 pp. 8408-8414
ISSN:
1520-5827
Subject:
Alzheimer disease, amyloid beta-peptides, brain, fluorescence microscopy, gels, humans, lipid bilayers, lipids, liquids, neurotoxicity, pathogenesis, plasma membrane, spectroscopy
Abstract:
Plasma membranes in the human brain can interact with amyloid β-peptide (1–42; Aβ₄₂) and induce Aβ₄₂ fibrillation, which is considered to be a crucial process underlying the neurotoxicity of Aβ₄₂ and the pathogenesis of Alzheimer’s disease (AD). However, the mechanism of membrane-mediated Aβ₄₂ fibrillation at the molecular level remains elusive. Here we study the role of adsorbed Aβ₄₂ peptides on membrane-mediated fibrillation using supported lipid bilayers of varying phase structures (gel and fluid). Using total internal reflection fluorescence microscopy and interfacial specific second-order nonlinear optical spectroscopy, we show that the dynamics of 2D-mobile Aβ₄₂ molecules, facilitated by the highly mobile lipids underneath the peptides, are critical to Aβ₄₂ fibrillation on liquid phase membranes. This growth mechanism is retarded on gel phase membranes where the dynamics of 2D-mobile peptides are restricted by the “frozen” lipids with less mobility.
Agid:
6072080