光谱和计算证据表明[FeFe]化酶仅使用CO桥接中间体
James A Birrell1, Vladimir Pelmenschikov2, Nakul Mishra3
1Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany.
Journal of the American Chemical Society
|December 11, 2019
概括
[FeFe]酶在它们的催化循环中使用过桥式碳基 (CO),而不是过桥式化物,在关键的中间状态中. 这一发现澄清了这些高活性转化酶的机制.
科学领域:
- 生物化学
- 酵素学
- 生物有机化学
背景情况:
- [FeFe]酶是转化 (H2) 的关键酶.
- 正确的催化机制,特别是减少的中间体 (HredH+和HsredH+) 的身份,是有争议的.
- 现有的模型建议在这些状态中使用半桥式CO或桥式化物.
研究的目的:
- 阐明[FeFe]酶中间体的结构和机制细节.
- 解决有关HredH+和HsredH+状态中的桥接CO与桥接的争议.
- 提供这些中间体的催化能力的实验证据.
主要方法:
- 低温红外 (IR) 光谱.
- 核共振振光谱 (NRVS) 的使用.
- 密度函数理论 (DFT) 的计算.
主要成果:
- 实验证据证实在HsredH+和HredH+状态中保留了一个桥梁碳 (CO).
- 在任何中间状态中都没有发现过桥化物的证据.
- 这些发现支持一种催化循环模型,其中这些状态是不可分割的和活跃的.
结论:
- 桥梁CO,而不是桥梁化物,存在于关键的[FeFe]酶中间体中.
- 在子集群之间进行质子合电子转移对于酶的效率和可逆性至关重要.
- 这项研究阐明了高活性H2转化酶的机制.
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