Probing the kinetics of β-amyloid self-association
Probing the kinetics of β-amyloid self-association
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DOI：
10.1006/jsbi.2000.4253
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发表时间：
2000-06-01
影响因子：
3
通讯作者：
Pallitto, MR
中科院分区：
文献类型：
--
作者：
Murphy, RM;Pallitto, MR
β-淀粉样肽（A β）从可溶性单体自发转化为不溶性纤维状沉淀物可能是与阿尔茨海默病相关的神经变性的基础。A β自缔合动力学的完整描述需要鉴定存在的低聚物种类和缔合途径，以及定量速率常数和反应级数。以前发表的工作描绘发展定量动力学模型的进展进行了简要回顾。描述了使用光散射来探测A β原纤维的大小和形状作为时间和浓度的函数，呈现了描述从尿素变性状态开始在生理pH下的A β自缔合的数据。高分子量物质在稀释后几分钟内迅速形成。在70亩M，主要的纤维物种的大小几乎是恒定的，而在280亩M两个人口被检测到，其中每个随时间的大小增加。在出现可见固相之前，通过动态光散射可靠地检测到初始沉淀。令人惊讶的是，沉淀物在最低浓度下最早出现，并且沉淀物的物理状态随浓度显著变化。凝胶扩散试验表明，单体A β从预形成的原纤维中解离，表明可逆的异质缔合必须被纳入任何现实的A β缔合模型中。(C)北京大学出版社.
Spontaneous conversion of beta-amyloid peptide (A beta) from soluble monomer to insoluble fibrillar precipitate may underlie the neurodegeneration associated with Alzheimer's disease. A complete description of A beta self-association kinetics requires identification of the oligomeric species present and the pathway of association, as well as quantitation of rate constants and reaction order. Previously published work delineating progress in developing quantitative kinetic models is reviewed briefly. The use of light scattering to probe A beta fibril size and shape as a function of time and concentration is described, Data describing A beta self-association at physiological pH starting from the urea-denatured state are presented. High-molecular-weight species formed rapidly, within minutes of dilution. At 70 mu M, the size of the major fibrillar species was virtually constant with time, whereas at 280 mu M two populations were detected, each of which increased in size with time. Incipient precipitation, prior to the appearance of a visible solid phase, was detected reliably by dynamic light scattering, Surprisingly, precipitates appeared earliest at the lowest concentration, and the physical state of the precipitate changed markedly with concentration. A gel diffusion assay showed that monomer A beta dissociates from preformed fibrils, indicating that reversible heterogeneous association must be incorporated into any realistic model of A beta association. (C) 2000 Academic Press.