Three-/four-repeat-dependent aggregation profile of tau microtubule-binding domain clarified by dynamic light scattering analysis.
Three-/four-repeat-dependent aggregation profile of tau microtubule-binding domain clarified by dynamic light scattering analysis.
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DOI：
10.1016/j.bbrc.2009.05.047
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发表时间：
2009-07
影响因子：
3.1
通讯作者：
Etsuko Sugino;Chisato Nishiura;K. Minoura;Y. In;M. Sumida;T. Taniguchi;K. Tomoo;T. Ishida
中科院分区：
文献类型：
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作者：
Etsuko Sugino;Chisato Nishiura;K. Minoura;Y. In;M. Sumida;T. Taniguchi;K. Tomoo;T. Ishida
由于tau微管结合结构域（MBD）的核心区域是形成tau丝的区域，因此分析其自组装机制可以为开发有效抑制tau丝形成的方法提供所需的信息。生物体的MBD结构域由3个或4个类似的31- 32位重复序列组成，分别是3RMBD （R134）和4RMBD （R1234）。利用β-片结构结合信号传感器硫黄素，利用荧光光谱研究了MBD的灯丝形成过程。这种方法间接地观察聚合，并且不提供关于聚合大小或体积随时间变化的信息。因此，为了确定引发MBD自结合所需的结构，动态光散射（DLS）方法被应用于分析3RMBD、4RMBD及其组成单重复的聚集，并被证明是直接分析灯丝形成的有力工具。DLS分析清楚地表明，引发聚集的构建单元是分子间的R3-R3二硫键二聚体3RMBD和分子内的R2-R3二硫键单体4RMBD，它们在生理条件下的聚集过程是不同的，这是传统荧光法无法清楚揭示的。本文所报道的MBD的重复数依赖的聚集模型，以及每个重复的功能，应该有助于设计一种防止tau PHF形成的方法。
The analysis of the self-assembly mechanism of the tau microtubule-binding domain (MBD) could provide the information needed to develop an effective method for the inhibition of the tau filament formation because of its core region that forms the filament. The MBD domain in the living body consists of similar three or four 31- to 32-residue repeats, namely 3RMBD (R134) and 4RMBD (R1234), respectively. The filament formation of the MBD has been mainly investigated by fluorescence spectroscopy utilizing the β-sheet structure-binding signal sensor thioflavin. This method observes the aggregation indirectly, and provides no information on the time-dependent change in aggregation size or volume. Thus, to determine the structure necessary for initiating MBD self-association, the dynamic light scattering (DLS) method was applied to the analysis of the aggregations of 3RMBD, 4RMBD and their component single repeats and shown to be a powerful tool for directly analyzing filament formation. DLS analysis clearly showed that the building unit for initiating the aggregation is the intermolecular R3–R3 disulfide-bonded dimer for 3RMBD and the intramolecular R2–R3 disulfide-bonded monomer for 4RMBD, and their aggregation processes under physiological condition differ from each other, which has not been clearly revealed by the conventional fluorescence method. The repeat-number-dependent aggregation model of MBD, together with the function of each repeat, reported in this paper should help to devise a method of preventing tau PHF formation.