Rapid α-oligomer formation mediated by the Aβ C terminus initiates an amyloid assembly pathway.
Rapid α-oligomer formation mediated by the Aβ C terminus initiates an amyloid assembly pathway.
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DOI：
10.1038/ncomms12419
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发表时间：
2016-08-22
影响因子：
16.6
通讯作者：
Wetzel R
中科院分区：
文献类型：
--
作者：
Misra P;Kodali R;Chemuru S;Kar K;Wetzel R
Since early oligomeric intermediates in amyloid assembly are often transient and difficult to distinguish, characterize and quantify, the mechanistic basis of the initiation of spontaneous amyloid growth is often opaque. We describe here an approach to the analysis of the Aβ aggregation mechanism that uses Aβ-polyglutamine hybrid peptides designed to retard amyloid maturation and an adjusted thioflavin intensity scale that reveals structural features of aggregation intermediates. The results support an aggregation initiation mechanism for Aβ-polyQ hybrids, and by extension for full-length Aβ peptides, in which a modular Aβ C-terminal segment mediates rapid, non-nucleated formation of α-helical oligomers. The resulting high local concentration of tethered amyloidogenic segments within these α-oligomers facilitates transition to a β-oligomer population that, via further remodelling and/or elongation steps, ultimately generates mature amyloid. Consistent with this mechanism, an engineered Aβ C-terminal fragment delays aggregation onset by Aβ-polyglutamine peptides and redirects assembly of Aβ42 fibrils. The elucidation of amyloid nucleation mechanisms remains challenging as early oligomeric intermediates are transient and difficult to distinguish. Here the authors use Aβ- polyglutamine hybrid peptides designed to slow and limit amyloid maturation to provide insights into the structures of Aβ self-assembly intermediates.
