Two-dimensional IR spectroscopy and isotope labeling defines the pathway of amyloid formation with residue-specific resolution
Two-dimensional IR spectroscopy and isotope labeling defines the pathway of amyloid formation with residue-specific resolution
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DOI：
10.1073/pnas.0805957106
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发表时间：
2009-04-21
影响因子：
11.1
通讯作者：
Zanni, Martin T.
中科院分区：
文献类型：
--
作者：
Shim, Sang-Hee;Gupta, Ruchi;Zanni, Martin T.
人们对揭示淀粉样蛋白形成的途径有相当大的兴趣，因为淀粉样蛋白的毒性特性可能来自前纤维中间体，而不是完全形成的纤维。利用最近发明的一种采集二维红外光谱和定点同位素标记的方法，我们测量了与2型糖尿病相关的37个残基多肽-人胰岛淀粉样多肽(HIAPP)在聚集过程中6个残基的二级结构的发展。通过对6个不同标记位点的动力学监测，我们发现这些多肽最初在靠近纤维有序环的链区形成了良好的有序结构，随后形成了2个平行的β-折叠，N-末端的β-折叠可能在C-末端折叠之前形成。这一实验方法提供了hIAPP纤维形成的聚集途径的详细视图，以及在不使用结构扰动标记的情况下研究其他淀粉样蛋白形成蛋白的一般方法。
There is considerable interest in uncovering the pathway of amyloid formation because the toxic properties of amyloid likely stems from prefibril intermediates and not the fully formed fibrils. Using a recently invented method of collecting 2-dimensional infrared spectra and site-specific isotope labeling, we have measured the development of secondary structures for 6 residues during the aggregation process of the 37-residue polypeptide associated with type 2 diabetes, the human islet amyloid polypeptide (hIAPP). By monitoring the kinetics at 6 different labeled sites, we find that the peptides initially develop well-ordered structure in the region of the chain that is close to the ordered loop of the fibrils, followed by formation of the 2 parallel beta-sheets with the N-terminal beta-sheet likely forming before the C-terminal sheet. This experimental approach provides a detailed view of the aggregation pathway of hIAPP fibril formation as well as a general methodology for studying other amyloid forming proteins without the use of structure-perturbing labels.