Dataset Information

Identification of a Novel Parallel β-Strand Conformation within Molecular Monolayer of Amyloid Peptide.

ABSTRACT: The differentiation of protein properties and biological functions arises from the variation in the primary and secondary structure. Specifically, in abnormal assemblies of protein, such as amyloid peptide, the secondary structure is closely correlated with the stable ensemble and the cytotoxicity. In this work, the early Aβ_33-42 aggregates forming the molecular monolayer at hydrophobic interface are investigated. The molecular monolayer of amyloid peptide Aβ_33-42 consisting of novel parallel β-strand-like structure is further revealed by means of a quantitative nanomechanical spectroscopy technique with force controlled in pico-Newton range, combining with molecular dynamic simulation. The identified parallel β-strand-like structure of molecular monolayer is distinct from the antiparallel β-strand structure of Aβ_33-42 amyloid fibril. This finding enriches the molecular structures of amyloid peptide aggregation, which could be closely related to the pathogenesis of amyloid disease.

SUBMITTER: Liu L

PROVIDER: S-EPMC5071675 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature

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Identification of a Novel Parallel β-Strand Conformation within Molecular Monolayer of Amyloid Peptide.

Liu Lei L Li Qiang Q Zhang Shuai S Wang Xiaofeng X Hoffmann Søren Vrønning SV Li Jingyuan J Liu Zheng Z Besenbacher Flemming F Dong Mingdong M

Advanced science (Weinheim, Baden-Wurttemberg, Germany) 20160408 6

The differentiation of protein properties and biological functions arises from the variation in the primary and secondary structure. Specifically, in abnormal assemblies of protein, such as amyloid peptide, the secondary structure is closely correlated with the stable ensemble and the cytotoxicity. In this work, the early Aβ<sub>33-42</sub> aggregates forming the molecular monolayer at hydrophobic interface are investigated. The molecular monolayer of amyloid peptide Aβ<sub>33-42</sub> consistin ...[more]

PMID: 27818898

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Project description:Membrane lipids play a pivotal role in the pathogenesis of Alzheimer's disease, which is associated with conformational changes, oligomerization and/or aggregation of Alzheimer's beta-amyloid (Abeta) peptides. Yet conflicting data have been reported on the respective effect of cholesterol and glycosphingolipids (GSLs) on the supramolecular assembly of Abeta peptides. The aim of the present study was to unravel the molecular mechanisms by which cholesterol modulates the interaction between Abeta(1-40) and chemically defined GSLs (GalCer, LacCer, GM1, GM3). Using the Langmuir monolayer technique, we show that Abeta(1-40) selectively binds to GSLs containing a 2-OH group in the acyl chain of the ceramide backbone (HFA-GSLs). In contrast, Abeta(1-40) did not interact with GSLs containing a nonhydroxylated fatty acid (NFA-GSLs). Cholesterol inhibited the interaction of Abeta(1-40) with HFA-GSLs, through dilution of the GSL in the monolayer, but rendered the initially inactive NFA-GSLs competent for Abeta(1-40) binding. Both crystallographic data and molecular dynamics simulations suggested that the active conformation of HFA-GSL involves a H-bond network that restricts the orientation of the sugar group of GSLs in a parallel orientation with respect to the membrane. This particular conformation is stabilized by the 2-OH group of the GSL. Correspondingly, the interaction of Abeta(1-40) with HFA-GSLs is strongly inhibited by NaF, an efficient competitor of H-bond formation. For NFA-GSLs, this is the OH group of cholesterol that constrains the glycolipid to adopt the active L-shape conformation compatible with sugar-aromatic CH-pi stacking interactions involving residue Y10 of Abeta(1-40). We conclude that cholesterol can either inhibit or facilitate membrane-Abeta interactions through fine tuning of glycosphingolipid conformation. These data shed some light on the complex molecular interplay between cell surface GSLs, cholesterol and Abeta peptides, and on the influence of this molecular ballet on Abeta-membrane interactions.

Dataset Information

Identification of a Novel Parallel β-Strand Conformation within Molecular Monolayer of Amyloid Peptide.

Publications

Identification of a Novel Parallel β-Strand Conformation within Molecular Monolayer of Amyloid Peptide.

Similar Datasets

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