Assembly of τ protein into Alzheimer paired helical filaments depends on a local sequence motif (306VQIVYK311) forming β structure
Assembly of τ protein into Alzheimer paired helical filaments depends on a local sequence motif (306VQIVYK311) forming β structure
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DOI：
10.1073/pnas.97.10.5129
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发表时间：
2000-05-09
影响因子：
11.1
通讯作者：
Mandelkow, E
中科院分区：
文献类型：
--
作者：
von Bergen, M;Friedhoff, P;Mandelkow, E
我们已经在tau蛋白中寻找了一个最小的相互作用基序，该基序支持聚集成阿尔茨海默氏症样的成对螺旋丝。用不同的蛋白酶消化重复结构域产生包含43个残基的GluC诱导的片段（称为PHF43），其代表tau的第三重复加上一些侧翼残基。该片段容易自组装成细丝而没有成对的螺旋外观，但是这些细丝高度胜任从全长tau使真正的PHF成核。探测PHF 43与来自完整tau序列的重叠肽的相互作用，在第三个内部重复序列的开始处产生最小的六肽相互作用基序（306）VQIVYK（311）。该基序与tau中预测的最高β结构潜力相一致。CD和傅里叶变换红外光谱表明，PHF 43获得明显的自组装条件下的β结构。通过脯氨酸扫描诱变在六肽区域中的点突变防止聚集。这些数据表明，PHF组装是由一个短片段，含有最小的相互作用基序形成一个本地β结构嵌入在一个很大的随机卷曲蛋白质。
We have searched for a minimal interaction motif in tau protein that supports the aggregation into Alzheimer-like paired helical filaments. Digestion of the repeat domain with different proteases yields a GluC-induced fragment comprising 43 residues (termed PHF43), which represents the third repeat of tau plus some flanking residues. This fragment self assembles readily into thin filaments without a paired helical appearance, but these filaments are highly competent to nucleate bona fide PHFs from full-length tau. Probing the interactions of PHF43 with overlapping peptides derived from the full tau sequence yields a minimal hexapeptide interaction motif of (306)VQIVYK(311) at the beginning of the third internal repeat. This motif coincides with the highest predicted beta-structure potential in tau. CD and Fourier transform infrared spectroscopy shows that PHF43 acquires pronounced beta structure in conditions of self assembly. Point mutations in the hexapeptide region by proline-scanning mutagenesis prevent the aggregation. The data indicate that PHF assembly is initiated by a short fragment containing the minimal interaction motif forming a local beta structure embedded in a largely random-coil protein.