单一域金属氨酸:人类MT 1a的超金属化
Duncan E K Sutherland1, Mathew J Willans, Martin J Stillman
1Department of Chemistry, University of Western Ontario, London, Ontario N6A 5B7, Canada.
Journal of the American Chemical Society
|January 17, 2012
概括
人类金属胺1a与第八个离子结合,形成了一个新的单域结构. 这种"超金属化"物种表明其双域结构崩,影响和铜的平衡.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 金属蛋白化学 金属蛋白化学
背景情况:
- 金属氨酸 (MTs) 是富含氨酸的蛋白质,参与金属排毒,氧化应激防御和必需金属 (,铜) 恒温.
- 人类金属氨酸1a (hMT1a) 已知可以结合多达七个Zn2+或Cd2+离子.
研究的目的:
- 研究过多的 (Cd(2+)) 与人类金属胺1a (hMT1a) 结合的结构后果.
- 描述"超金属化"Cd(2+) -hMT1a物种的形成和结构.
主要方法:
- 电子喷雾电离质谱仪 (ESI-MS) 用于确定化状态.
- 循环二重化 (CD) 光谱法用于分析结构变化.
- (113) 核磁共振 (NMR) 光谱 (直接和间接) 来阐明结构细节.
主要成果:
- 形成了一种新的Cd(8) -βα-rhMT 1a物种,表明第八个Cd(2+) 离子的结合超出了已知的容量.
- 在Cd(8) 结合时CD光谱的显著变化,表明集群对称性丧失和两域结构的潜在崩.
- (113) Cd NMR 数据表明,与Cd(8) -βα-rhMT 1a相比,Cd(8) -βα-rhMT 1a的光谱形状简化,支持结构凝聚.
结论:
- 第八个Cd2+) 离子坐标通过两个MT域的协调作用,导致潜在的单域"超域"结构.
- 这种结构转变代表了哺乳动物金属氨酸中的新型金属结合方式.
- 这些发现为金属离子度的反应中metallothioneins的动态结构可塑性提供了洞察力.
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