在 (III) 氨酸上进行水交换. 有关氧气演变复合体和超氧化物变异催化剂的机制见解
Dominik Lieb1, Achim Zahl, Tatyana E Shubina
1Friedrich-Alexander-Universität Erlangen-Nürnberg, Department Chemie und Pharmazie, Egerlandstr. 1, 91058 Erlangen, Germany.
Journal of the American Chemical Society
|May 14, 2010
概括
(III) 氨酸的水交换是一个快速的过程,对于理解生物系统如光系统II和超氧化物变异的催化机制至关重要.
科学领域:
- 无机化学 无机化学
- 生物有机化学 生物有机化学
- 物理化学 物理化学
背景情况:
- (III) 中心在生物过程中至关重要,包括光系统II.
- 了解Mn (III) 上的水交换动力学是阐明反应机制的关键.
研究的目的:
- 通过实验确定Mn (III) 氨酸复合物的水交换速率常数和激活参数.
- 为了研究氨酸电荷和转链体对水交换动态的影响.
主要方法:
- 使用了取决于温度和压力的 (17) O核磁共振 (NMR) 技术.
- 用人密度函数理论 (DFT) 计算用于理论支持.
主要成果:
- 在Mn (III) 氨酸上建立了水交换,作为一个快速的过程 (k (ex) ≈ 10^7 s (-1)) 与I (d) 到I机制.
- 证明了汇率对氨酸电荷和转链体的最小依赖,归因于Jahn-Teller效应和对的有效电荷.
- DFT的计算证实了Mn(III) -OH(2) 债券长度的轻微变化,并表明Mn中心的有效负荷较低.
结论:
- 在Mn(III) 氨酸上快速的水交换为我们提供了关于光系统II中基质结合的见解.
- 这些发现支持Mn中心在超氧化物变异的内球催化通路中的潜在作用.
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