A bioinspired redox relay that mimics radical interactions of the Tyr-His pairs of photosystem II
A bioinspired redox relay that mimics radical interactions of the Tyr-His pairs of photosystem II
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DOI：
10.1038/nchem.1862
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发表时间：
2014-05-01
期刊：
影响因子：
21.8
通讯作者：
Moore, Ana L.
中科院分区：
文献类型：
--
作者：
Megiatto, Jackson D., Jr.;Mendez-Hernandez, Dalvin D.;Moore, Ana L.
在氧化水的光合生物中，光吸收在光系统II反应中心产生一种强氧化叶绿素复合物（P680（中心点+））。这通过来自含锰水氧化催化剂的电子转移途径被还原，所述含锰水氧化催化剂包括电子转移中继，所述电子转移中继包含酪氨酸（Tyr）-组氨酸（His）对，其特征在于酚基和咪唑基之间的氢键。通过快速还原P680（中心点+），继电器被认为可以减轻复合反应，从而确保水氧化的高量子产率。在这里，我们表明，一个人工反应中心，具有苯并咪唑-苯酚模型的Tyr-His对模仿短的内部氢键在光系统II和，使用电子顺磁共振光谱，伴随质子耦合电子转移的热弛豫。虽然这个人工系统比自然系统简单得多，但理论表明，它抓住了继电器功能中重要的基本特征。
In water-oxidizing photosynthetic organisms, light absorption generates a powerfully oxidizing chlorophyll complex (P680(center dot+)) in the photosystem II reaction centre. This is reduced via an electron transfer pathway from the manganese-containing water-oxidizing catalyst, which includes an electron transfer relay comprising a tyrosine (Tyr)-histidine (His) pair that features a hydrogen bond between a phenol group and an imidazole group. By rapidly reducing P680(center dot+), the relay is thought to mitigate recombination reactions, thereby ensuring a high quantum yield of water oxidation. Here, we show that an artificial reaction centre that features a benzimidazole-phenol model of the Tyr-His pair mimics both the short-internal hydrogen bond in photosystem II and, using electron paramagnetic resonance spectroscopy, the thermal relaxation that accompanies proton-coupled electron transfer. Although this artificial system is much less complex than the natural one, theory suggests that it captures the essential features that are important in the function of the relay.