Clarification of amyloid fibrillation mechanism by modulating intraproteinaceous structure

通过调节蛋白质内结构阐明淀粉样纤维颤动机制

基本信息

批准号：
17570132
负责人：
TACHIBANA Hideki
金额：
$ 1.66万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17570132/
关键词：
Protein Amyloid Disulfide Lysozyme Nucleation beta-structure Hydrogen deuterium-exchange

项目摘要

1. The amyloid-fibrillation reaction of a lysozyme all-disulfide-deficient variant, 0SS, depends on salt-concentration and pH in such a way that the screening of the protein positive charge facilitates the fibrillation. It conforms to a nucleation-elongation reaction scheme and there exists critical monomer concentrations. A nucleus size varies with varying salt-concentration and pH. The absolute value of the dissociation rate constant of monomeric unit from the end of fibrillar polymer was obtained using a theoretical equation derived for the purpose by taking the length-distribution of fibrils into account. There exists a large, as much as three-orders of magnitude, variation in the fibrillation rate among the four 1SS variants, which collectively have a various kinds of tertiary constraints and intramolecular structures, implying that the N- and C-terminal regions should be apart from each other for efficient protofibril formation. The fibril diameter as obtained from SAXS measureme … More nt differs significantly among the 1SS variants. Moreover, the fibril of a 4SS molecule differs markedly in both morphology and diameter from the fibrils of 0SS and 1SS. Thus, the reaction rate and mechanism of fibrillation are strongly modulated by the kinds and amount of intraprotein structures.2. By using NMR-detected H/D-exchange the peptide regions protected from the exchange by virtue of structure formation were identified : in the 0SS fibril they are four peptide regions, each spanning seven to nine residues, which coincide with the regions of both high hydrophobicity and beta-propensity While the fibrils of two 1SS species show protected regions similar to those of 0SS fibril, the fibrils of the other 1SS species show different protected regions. Moreover, these protected regions altogether differ from the core region of WT lysozyme fibril. Thus, the kinds and amount of intraprotein structure modulate the peptide regions involved in nucleation and elongation of amyloid fibrillation. Less

1。溶菌酶全丝虫缺乏型变体的淀粉样蛋白 - 原纤维反应0SS，取决于盐分光度和pH，以筛选蛋白质阳性电荷功能的筛查。它符合核延长反应方案，并且存在关键的单体浓度。核大小的品种，具有不同的盐分浓度和pH。通过考虑原纤维的长度分布，使用为目的得出的理论方程获得了单体单位从原纤维聚合物末端的离解速率常数的绝对值。在四个1SS变体之间，纤维速率的变化很大，多达三个数量级，它们统称具有各种类型的第三级约束和分子内结构，这意味着N-和C-末端应彼此分开以获得有效的原始原状形成。从SAXS测量中获得的原纤维直径……在1SS变体之间显着差异。此外，4SS分子的原纤维在形态和直径上与0SS和1SS的原纤维明显不同。这是，纤颤的反应速率和机制受肾上蛋白结构的种类和量强烈调节。2。通过使用NMR检测的h/d-t-交换，确定了通过结构形成保护不受交换的胡椒区域：在0ss纤维中，它们是四个肽区域，每个肽区域均跨越了7至9个残留物，它们与高疏水性和beta抗性的区域相吻合，同时又显示了两种纤维的纤维，并显示了两种纤维的纤维群体，而这些区域均与两种纤维相似。其他1SS物种的原纤维显示出不同的受保护区域。此外，这些受保护的区域与WT溶菌酶原纤维的核心区域完全不同。这就是肾上蛋白结构的种类和量调节淀粉样蛋白纤维化的成核和伸长的肽区域。较少的