Amyloid β-Protein C-Terminal Fragments: Formation of Cylindrins and β-Barrels
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- 作者：Thanh D. Do ; Nichole E. LaPointe ; Rebecca Nelson ; Pascal Krotee ; Eric Y. Hayden ; Brittany Ulrich ; Sarah Quan ; Stuart C. Feinstein ; David B. Teplow ; David Eisenberg ; Joan-Emma Shea ; Michael T. Bowers
- 刊名：Journal of the American Chemical Society
- 出版年：2016
- 出版时间：January 20, 2016
- 年：2016
- 卷：138
- 期：2
- 页码：549-557
- 全文大小：604K
- ISSN：1520-5126
文摘
In order to evaluate potential therapeutic targets for treatment of amyloidoses such as Alzheimer’s disease (AD), it is essential to determine the structures of toxic amyloid oligomers. However, for the amyloid β-protein peptide (Aβ), thought to be the seminal neuropathogenetic agent in AD, its fast aggregation kinetics and the rapid equilibrium dynamics among oligomers of different size pose significant experimental challenges. Here we use ion-mobility mass spectrometry, in combination with electron microscopy, atomic force microscopy, and computational modeling, to test the hypothesis that Aβ peptides can form oligomeric structures resembling cylindrins and β-barrels. These structures are hypothesized to cause neuronal injury and death through perturbation of plasma membrane integrity. We show that hexamers of C-terminal Aβ fragments, including Aβ(24–34), Aβ(25–35) and Aβ(26–36), have collision cross sections similar to those of cylindrins. We also show that linking two identical fragments head-to-tail using diglycine increases the proportion of cylindrin-sized oligomers. In addition, we find that larger oligomers of these fragments may adopt β-barrel structures and that β-barrels can be formed by folding an out-of-register β-sheet, a common type of structure found in amyloid proteins.