蛋白酶的四面体中间体的初始QM/MM动态模拟:对活性位点结网络的洞察
Maya Topf1, Peter Várnai, W Graham Richards
1Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ, United Kingdom. graham.richards@chem.ox.ac.uk
Journal of the American Chemical Society
|December 6, 2002
概括
量子力学/分子力学模拟显示,蛋白酶四面体中间体是稳定的. 关键的键稳定了这种结构,这表明没有"环翻转机制"的解液的途径.
科学领域:
- 生物化学 生物化学
- 计算化学的计算化学
- 结构生物学 结构生物学
背景情况:
- 弹性酶通过涉及四面体中间体的脱氧化步骤催化水解.
- 了解这种中间体的稳定性和动态性对于阐明酶机制至关重要.
- 之前的研究提出了一个
- 环翻机械 环翻机械
- 基于NMR数据的数据.
研究的目的:
- 研究弹性酶催化水解中的四面体中间体的稳定性和结构动力学.
- 为了确定关键的稳定相互作用,并探索脱化途径.
- 检查质子转移和潜在产品释放机制的作用.
主要方法:
- 一开始的量子力学/分子力学 (QM/MM) 动力学模拟.
- 扩展的量子区域包括催化三位一体,四面体中间体和氧化离子孔.
- 对几何,动态和键特性进行分析.
主要成果:
- 四面体中间体在皮秒时间尺度上是一个稳定的物种.
- 在Asp-102/His-57和中间体的氧与Gly-193 (氧化离子孔) 之间确定了关键的稳定键.
- 观测到的伊米达环的移动性表明,与拟议的"环翻转机制"不同的脱基化途径,涉及与Thr-213的替代键.
结论:
- 蛋白酶中的四面体中间体在结构上稳定,并通过特定的键稳定.
- 提出了一种新的脱途径,绕过了"环翻转机制"的需要.
- 产品释放可能通过破坏氧离子孔相互作用和循环动力学来促进.
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