Huraskin D, Horn A (2019)
Publication Type: Journal article
Publication year: 2019
Book Volume: 25
Article Number: 37
Journal Issue: 2
DOI: 10.1007/s00894-018-3920-4
Alzheimer's disease is characterized by the aggregation of Amyloid-beta (A beta) peptide into oligomers, fibrils and plaques. Many factors influencing this process as well as the stability of the various A beta aggregates are known to date, and include the concentration and type of metal ions. Most experimental and theoretical studies have concentrated on heavy metal ions, like Fe2+, Zn2+, or Cu2+, while the smaller alkali ions Li+, Na+, and K+ have not gained much attention notwithstanding their role and ubiquity in physiological environments. In this work, we applied atomistic molecular dynamics simulations to investigate the potential role of these alkali ions in stabilizing fibrillar A beta oligomers of different size and topology, i.e., single and double filament systems comprising 3-24 peptide chains per filament. We find a pronounced difference on the molecular level in the interaction behavior with free carboxylate groups of the A beta oligomer: Li+ forms stable bridged interactions, whereas K+ interacts more transiently and lacks bridging. The behavior of Na+ is in between, so that this ion-protein interaction obeys the renowned Hofmeister series. These differences are also reflected in the ability of the alkali ions to stabilize the oligomer secondary structure. The stabilizing effect is most pronounced for the smaller fibrillar oligomers, suggesting that the type of alkali ion critically affects the initial stages of fibril formation. Our findings thus offer a molecular explanation for the observation that the polymorphisms of A beta fibril structures are caused by differences in the surrounding ionic environment.
APA:
Huraskin, D., & Horn, A. (2019). Alkali ion influence on structure and stability of fibrillar amyloid-beta oligomers. Journal of Molecular Modeling, 25(2). https://dx.doi.org/10.1007/s00894-018-3920-4
MLA:
Huraskin, Danyil, and Anselm Horn. "Alkali ion influence on structure and stability of fibrillar amyloid-beta oligomers." Journal of Molecular Modeling 25.2 (2019).
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