Fourier Transform Infrared Analysis of the S-State Cycle of Water Oxidation in the Microcrystals of Photosystem II
Fourier Transform Infrared Analysis of the S-State Cycle of Water Oxidation in the Microcrystals of Photosystem II
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DOI：
10.1021/acs.jpclett.8b00638
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发表时间：
2018-05-03
影响因子：
5.7
通讯作者：
Noguchi, Takumi
中科院分区：
文献类型：
--
作者：
Kato, Yuki;Akita, Fusamichi;Noguchi, Takumi
在光系统II中，光合作用的水氧化是通过水氧化中心的称为S态(S-0-S-4)的中间产物的光驱动循环来进行的。时间分辨连续飞秒结晶学(SFX)最近被应用于PSII的微晶，以获得这些中间体的结构信息。然而，这些反应是否在整个S态循环中有效地进行，保持了PSII晶体中中间体的天然结构，目前还没有答案。我们用闪光诱导傅里叶变换红外(FTIR)差分光谱研究了PSII微晶中的水氧化反应。与溶液中的红外光谱相比，微晶中的所有亚稳态中间体都保持了原有的结构，S态的跃迁效率仍然较高，但S-2->；S-3和S-3->；S-0的跃迁效率略有降低，可能是由于晶体中水的运动的限制。
Photosynthetic water oxidation is performed in photosystem II (PSII) through a light-driven cycle of intermediates called S states (S-0-S-4) at the water oxidizing center. Time-resolved serial femtosecond crystallography (SFX) has recently been applied to the microcrystals of PSII to obtain the structural information on these intermediates. However, it remains unanswered whether the reactions efficiently proceed throughout the S-state cycle retaining the native structures of the intermediates in PSII crystals. We investigated the water oxidation reactions in the PSII microcrystals using flash-induced Fourier transform infrared (FTIR) difference spectroscopy. In comparison with the FTIR spectra in solution, it was shown that all of the metastable intermediates in the microcrystals retained their native structures, and the efficiencies of the S-state transitions remained relatively high, although those of the S-2 -> S-3 and S-3 -> S-0 transitions were slightly lowered possibly due to some restriction of water movement in the crystals.