Investigation of α-synuclein fibril structure by site-directed spin labeling
Investigation of α-synuclein fibril structure by site-directed spin labeling
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DOI：
10.1074/jbc.m700368200
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发表时间：
2007-08-24
影响因子：
4.8
通讯作者：
Langen, Ralf
中科院分区：
文献类型：
--
作者：
Chen, Min;Margittai, Martin;Langen, Ralf
α-突触核蛋白的错误折叠和原纤维形成在神经退行性疾病如帕金森病中起重要作用。在这里，我们使用电子顺磁共振光谱，结合定点自旋标记，研究α-突触核蛋白原纤维的结构特征。我们从总共83种不同的自旋标记衍生物产生原纤维，并观察到位于α-突触核蛋白原纤维核心区域内的所有位点中的大多数的单线交换窄化EPR谱。这种交换窄化需要紧密接触的多个自旋标记之间的轨道重叠。因此，α-突触核蛋白原纤维的核心区域必须排列成平行的对齐结构，其中来自不同分子的相同残基彼此堆叠。这个平行的、对齐的核心区域从残基36延伸到残基98，并且被紧密地封装。只有核心区域内的少数位点，例如位于NAC区域起始处的残基62-67，以及核心区域外的N-和C-末端区域，是明显较不有序的。与可接近性测量一起，表明原纤维内潜在α-折叠区域的位置，数据为生成三维模型提供了重要的结构约束。此外，数据支持新出现的观点，即平行的，在寄存器结构是一个共同的特点，由一些自然发生的淀粉样蛋白原纤维。
The misfolding and fibril formation of alpha- synuclein plays an important role in neurodegenerative diseases such as Parkinson disease. Here we used electron paramagnetic resonance spectroscopy, together with site-directed spin labeling, to investigate the structural features of alpha- synuclein fibrils. We generated fibrils from a total of 83 different spin- labeled derivatives and observed single-line, exchange-narrowed EPR spectra for the majority of all sites located within the core region of alpha- synuclein fibrils. Such exchange narrowing requires the orbital overlap between multiple spin labels in close contact. The core region of alpha- synuclein fibrils must therefore be arranged in a parallel, inregister structure wherein same residues from different molecules are stacked on top of each other. This parallel, in-register core region extends from residue 36 to residue 98 and is tightly packed. Only a few sites within the core region, such as residues 62-67 located at the beginning of the NAC region, as well as the N- and C- terminal regions outside the core region, are significantly less ordered. Together with the accessibility measurements that suggest the location of potential alpha- sheet regions within the fibril, the data provide significant structural constraints for generating three-dimensional models. Furthermore, the data support the emerging view that parallel, in-register structure is a common feature shared by a number of naturally occurring amyloid fibrils.