对氨酸酸酶机制的密度功能研究:I. 中间阵容的形成
Dilipkumar Asthagiri1, Valerie Dillet, Tiqing Liu
1Department of Molecular Biology, TPC-15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Journal of the American Chemical Society
|August 22, 2002
概括
蛋白质氨酸酸酶通过转移酸盐组来催化反应. 这项研究支持一种涉及离子基质的分离途径,其能量屏障比以前提出的要低.
科学领域:
- 生物化学 生物化学
- 计算化学的计算化学
- 酶学 是一种酶学.
背景情况:
- 蛋白氨酸酸酶 (PTPs) 是调节细胞信号的关键酶.
- 最初的催化步骤涉及从基质到活性部位的素转移.
- 关于基质电荷 (单离子与二离子) 和反应途径 (结合式与离合式) 的机制含糊性存在.
研究的目的:
- 阐明蛋白质氨酸酸酶活性第一步的催化机制.
- 为了研究基质电荷对反应路径和能量屏障的影响.
- 在酶的活性部位环境中计算模拟光转移反应.
主要方法:
- 用连续电静态建模的活点集群的组合密度函数计算.
- 计算了单离子和二离子基板路径的能量障碍和几何结构.
- 将计算预测与现有实验证据进行比较.
主要成果:
- 预测Dianionic基板具有早期质子转移的分离途径,产生9kcal/mol的能量屏障.
- 预测对单离子基质有较晚的质子转移的关联途径,产生22kcal/mol的能量屏障.
- 迪亚尼子通路的预测屏障更好地与实验估计 (约. 14 kcal/mol) 的时间.
结论:
- 这些发现支持一种催化机制,涉及二基质和蛋白质氨酸酸酶的离散反应途径.
- 这种机制与经典有机化学反应路径原理一致.
- 计算建模为酶催化机制提供了宝贵的见解.
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