通过多尺度模拟揭示光系统II中氨酸驱动的脱质的机制
Jinchan Liu1, Ke R Yang2, Julianne S Lampert3
1Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, United States.
Journal of the American Chemical Society
|February 23, 2026
概括
摄影系统II 摄影系统II
科学领域:
- 生物化学和生物物理学
- 光合作用研究研究 光合作用研究
- 水氧化的分子机制
背景情况:
- 光系统II (PSII) 在其氧进化复合体 (OEC) 中使用Mn4Ca集群,通过S状态过渡进行光驱动的水氧化.
- S2 → S3 过渡涉及氧化还原事件和质子释放,但精确的合机制尚不清楚.
- 来自TR-SFX,PBD,TR-XAS和EPR的现有实验数据显示电子和质子转移的动力学是相互矛盾的.
研究的目的:
- 为了协调PSII S2 → S3过渡的实验动力学数据中的差异.
- 为了阐明将氨酸YZ氧化与质子释放联系起来的原子化机制.
- 研究键动态和离子在氧化还原合质子运输中的作用.
主要方法:
- 量子力学/分子力学 (QM/MM) 模拟.
- 分子动力学 (MD) 模拟.分子动力学 (MD) 模拟.
- 在时间解析的连续秒晶体学 (TR-SFX) 中观察到的短暂电子密度转移的分析.
主要成果:
- 模拟显示,YZ氧化破坏了键对称性,取代了YZ并模仿了早期的TR-SFX信号.
- 一个通过键传播的静电信号通过Cl1通道触发了氧化还原合脱质.
- 恢复键对称度30μs解释了TR-SFX密度差异在没有YZ减小的情况下消失.
- O6*密度归因于水的重组,而不是与Ca结合的氧化物.
结论:
- 一个新的机制解释了PSII S2 → S3过渡,调和相互矛盾的实验数据.
- 键动态对于调解长距离质子运输与氧化还原事件相结合至关重要.
- 离子可能在促进OEC内的质子转移方面发挥着功能性作用.
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