β及其组成片段的溶液结构:与粉样沉积的关系
1Suntory Institute for Bioorganic Research, Osaka, Japan.
Science (New York, N.Y.)
|July 12, 1991
概括
阿尔茨海默病的粉样 (1-42) 和 (1-39) 在不同的pH值下形成阿尔法螺旋结构. 介质pH会诱导β结构,这表明pH的变化是粉样斑块形成和β自组合的关键.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 神经科学是一个神经科学.
背景情况:
- 阿尔茨海默病的特点是粉样蛋白斑块,主要由粉样蛋白β (Aβ) 组成.
- 甲β (1-42) 存在于斑块核中,而更容易溶解的甲β (1-39) 存在于脑血管粉样蛋白中.
- 溶液中的Aβ的结构性质对于理解粉样蛋白形成至关重要.
研究的目的:
- 为了研究合成和自然存在的粉样β (Aβ) 和溶液中的碎片的二次结构.
- 阐明pH和特定片段在Aβ的自我组装和结构转变中的作用.
主要方法:
- 循环二元化 (CD) 光谱分析二次结构.
- 二维核磁共振 (2D NMR) 光谱仪用于详细的结构分析.
- 通过各种pH值,溶剂和温度进行的研究.
主要成果:
- 在低和高pH下,Aβ (1-28),Aβ (1-39) 和Aβ (1-42) 采用单体α-螺旋结构.
- 在中间pH (4-7),这些主要形成寡合β结构,类似于粉样斑块中发现的结构.
- 疏水性炭基末端段,Aβ (29-42),只形成寡合β片,表明其在指导Aβ (1-42) 折叠中的作用.
结论:
- 粉样β并不是固有的不溶性; pH 值的变化对其自我组装和沉积至关重要.
- 局部或与年龄相关的pH值变化可能会引发粉样斑块的形成.
- Aβ (29-42) 分段是粉样斑块特征的β折叠板结构的关键决定因素.
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