光系II的次单元之间的激发能量转移的动态
Yusuke Yoneda1, Tetsuro Katayama1, Yutaka Nagasawa1,2,3
1Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka560-8531, Japan.
Journal of the American Chemical Society
|August 20, 2016
概括
与单体相反,光系统II核心复合体 (PSII-CC) 在高光强度下表现出高效的激子-激子灭绝. 这一过程限制了二极管中的电荷分离,影响了能量传递动态.
科学领域:
- 光合作用研究
- 生物物理
- 摄影化学
背景情况:
- 光系统II对于光合作用中的光依赖反应至关重要.
- 了解光合作用II核心复合体 (PSII-CC) 中的能量转移是阐明光合作用效率的关键.
- 单体和二元形式的PSII-CC可能表现出不同的光物理行为.
研究的目的:
- 研究和比较光系统II核心复合体 (PSII-CC) 的单体和二元形式的能量转移动态.
- 探索激发强度对这些动态的影响,特别关注激发-激发灭绝.
- 模拟观察到的消灭动态及其对电荷分离的影响.
主要方法:
- 使用Femtosecond暂时吸收 (TA) 光谱探测超快速的能量传递过程.
- 在不同激发强度下进行实验,以观察强度依赖的效应.
- 基于二项定理的数学模型被用来分析消灭动力学.
主要成果:
- 在低激发强度 (≤21nJ) 时,没有观察到单体和二元PSII-CC之间的TA动态显著差异.
- 在较高的强度下,加速的地面状态漂白回收,表明激子-激子消灭,在二次体中更为明显.
- 与单体相比,二元体的动态更依赖激发强度,这表明由于单体间的能量转移而导致有效的消灭.
结论:
- 在PSII-CC二次体中,高激发强度发生有效的激发-激发灭绝.
- 这种由单体单位之间的能量转移驱动的消灭过程极大地影响了能量动态.
- 尽管有两个反应中心,PSII-CC二极管似乎只支持单个电荷分离状态的消灭后,影响整体效率.
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