高层植物的氧化水是否有不同的机制?
Yu-Tian Song1, Xi-Chen Li1, Per E M Siegbahn2
1College of Chemistry, Beijing Normal University, Beijing 100875, China.
The journal of physical chemistry. B
|July 19, 2023
概括
光系II中氧气进化的无水结合机制在能量上是不利的. 添加水将系统恢复到已建立的氧-氧机制,这表明它仍然是氧气形成的主要途径.
科学领域:
- 生物化学 生物化学
- 光合作用研究研究光合作用.
- 量子化学是一种量子化学.
背景情况:
- 十多年来,氧-氧机制一直是光系II (PSII) 中氧 (O2) 演变的公认模型.
- 最近的批评提出了一种无水结合 (WU) 机制,涉及对Mn{\displaystyle V} O组的核友性攻击.
研究的目的:
- 调查在PSII中O2形成的拟议的无水系 (WU) 机制的能源可行性.
- 为了比较WU机制与以前建立的途径.
主要方法:
- 对反应路径的计算研究.
- 对反应物和过渡状态的能量计算.
主要成果:
- 发现WU机制是先前提出的路径的高能变体.
- 将一个水分子添加到Mn(V) O中心的过程具有极高的运动性.
- 该系统在添加水后恢复到氧基-氧基机制.
结论:
- 与氧基-基机制相比,无水结合机制在能量方面处于不利地位.
- 氧基-氧基机制仍然是高层植物O2进化最合理的途径.
- 水与Mn(V) O中心结合,将反应带回已建立的氧基-氧基通路.
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