电核双共振光谱学证据表明,氧桥核参与了双核酶的催化
Stoyan K Smoukov1, Luca Quaroni, Xuedong Wang
1Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|March 14, 2002
概括
这项研究使用电子核双共振 (ENDOR) 光谱来研究紫酸酸酶. 这些发现揭示了一个桥梁氧化物,而不是终端氧化物,是子宫铁素催化的关键.
科学领域:
- 生物化学 生物化学
- 生物物理化学 生物物理化学
- 酶学 是一种酶学.
背景情况:
- 紫酸酸酶 (PAP) 是参与酸代谢的关键酶.
- 了解活性位点的溶剂协调对于阐明PAP催化机制至关重要.
- 之前的晶体结构缺乏活性酶中溶剂配体的直接证据.
研究的目的:
- 为了识别与子宫素 (Uf) 的活性二金属中心协调的溶剂分子.
- 调查溶剂衍生联体在UF的催化机制中的作用.
- 确定 Uf 中溶剂分子及其复合物与 MoO ((4), AsO ((4) 和 PO ((4) 的协调.
主要方法:
- 使用了 (2) H Q 波段 (35 GHz) 脉冲电子核双共振 (ENDOR) 光谱.
- 分析了子宫铁素二金属中心的活性混合价值 (Fe(3+) Fe(2+)) 形式.
- 在其原始状态和与酸盐,酸盐和酸盐离子复合体中检查了Uf.
主要成果:
- 在Uf的双核中心确定了一个桥接氧化物和一个与Fe ((2+) 结合的终端水/氧化物.
- 没有发现与Fe3+) 中心结合的终端水/氧化.
- 在离子结合时观察到终端水的损失,而桥接氧化物仍然存在.
结论:
- 结果排除了涉及终端Fe(3+) 结合核的水解机制.
- 这些发现支持一种催化机制,其中桥接氧化物充当核友的作用.
- 这项研究提供了直接的光谱证据,证明了溶剂衍生联体在PAP催化中的作用.
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