超交换电子转移和蛋白质矩阵在光合作用反应中心的电荷分离过程中
Keisuke Saito1,2, Hiroyuki Tamura1,2, Hiroshi Ishikita1,2
1Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan.
The journal of physical chemistry letters
|August 30, 2024
概括
通过D2-Trp253的超交换合显著增强了光系统II中从酸到酸的电子转移. 当地蛋白质相互作用,如H键,进一步促进这个过程,对于光合作用至关重要.
科学领域:
- 生物化学 生物化学
- 光合作用研究研究光合作用.
- 分子生物物理学的分子生物物理学.
背景情况:
- 类型II反应中心,包括光系统II (PSII) 和紫色细菌反应中心 (PbRC),利用光诱导的电荷分离.
- 电子从丁 (PheoD1) 转移到 (QA) 是一个关键的步骤,发生在保存的三甲残留物附近.
研究的目的:
- 在PSII蛋白环境中研究PheoD1和QA之间的电子转移途径.
- 量化超交换合 (dakdakH_PheoD1···QAdak) 和其对电子转移效率的贡献.
主要方法:
- 超交换合路径的计算分析.
- 研究保存的D2-Trp253残留物的作用.
- 评估蛋白质环境和突变 (D2-W253F) 对电子转移速率的影响.
主要成果:
- 通过D2-Trp253 ([Trp]•−类中间体) 的超交换合比直接电子转移 (0.13 meV) 大得多 (0.73 meV),这表明超交换占主导地位.
- 局部蛋白质相互作用,特别是键,通过移位分子轨道来增强超级交换.
- D2-W253F突变大大降低了电子转移速率.
结论:
- 通过D2-Trp253进行超交换合是PSII中PheoD1-QA电子转移的主要机制.
- 蛋白质环境,特别是H键,在调节超交换效率方面发挥着关键作用.
- 保存的残留物分化了超交换合,影响了电子转移分支的活性.
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