Infrared nanospectroscopy characterization of oligomeric and fibrillar aggregates during amyloid formation.
Infrared nanospectroscopy characterization of oligomeric and fibrillar aggregates during amyloid formation.
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DOI：
10.1038/ncomms8831
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发表时间：
2015-07-28
影响因子：
16.6
通讯作者：
Dietler G
中科院分区：
文献类型：
--
作者：
Ruggeri FS;Longo G;Faggiano S;Lipiec E;Pastore A;Dietler G
淀粉样蛋白是不溶性蛋白质纤维状聚集体。由于其与人类疾病和材料科学应用的联系，确定其聚集特征的重要性稳步增加。特别地，共济失调蛋白-3的Josephin结构域的错误折叠和聚集与脊髓小脑共济失调-3有关。红外纳米光谱，同时利用原子力显微镜和红外光谱，可以表征在纳米级的蛋白质的构象重排在其聚集。在这里，我们证明，我们可以单独表征低聚物和纤维状物质形成沿着淀粉样蛋白聚集。我们描述了它们的二级结构，在纳米尺度上监测α到β的转变，并将这些研究与其内在刚度演变的独立测量相结合。这些结果表明，Josephin的聚集收益从单体状态的球形中间体与天然结构的形成。这些中间体只是依次演变成错误折叠的聚集体和最终的原纤维。 神经退行性疾病的发作在分子水平上与称为淀粉样蛋白的不溶性蛋白质聚集体相关。在这里，作者通过红外纳米光谱和纳米力学研究表征了单个物种尺度上的淀粉样蛋白聚集。
Amyloids are insoluble protein fibrillar aggregates. The importance of characterizing their aggregation has steadily increased because of their link to human diseases and material science applications. In particular, misfolding and aggregation of the Josephin domain of ataxin-3 is implicated in spinocerebellar ataxia-3. Infrared nanospectroscopy, simultaneously exploiting atomic force microscopy and infrared spectroscopy, can characterize at the nanoscale the conformational rearrangements of proteins during their aggregation. Here we demonstrate that we can individually characterize the oligomeric and fibrillar species formed along the amyloid aggregation. We describe their secondary structure, monitoring at the nanoscale an α-to-β transition, and couple these studies with an independent measurement of the evolution of their intrinsic stiffness. These results suggest that the aggregation of Josephin proceeds from the monomer state to the formation of spheroidal intermediates with a native structure. Only successively, these intermediates evolve into misfolded aggregates and into the final fibrils. The onset of neurodegenerative disorders is associated at the molecular level with insoluble protein aggregates, named amyloids. Here, the authors characterize by infrared nanospectroscopy and nanomechanical studies, the amyloid aggregation at the individual species scale.