Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Aichi, Japan.
Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
J Phys Chem Lett. 2020 Oct 15;11(20):8908-8913. doi: 10.1021/acs.jpclett.0c02411. Epub 2020 Oct 6.
The high-spin S state was investigated with photosystem II (PSII) from spinach, , and . In extrinsic protein-depleted PSII, high-spin electron paramagnetic resonance (EPR) signals were not detected in either species, whereas all species showed ∼ 5 signals in the presence of a high concentration of Ca instead of the multiline signal. In the intact and PsbP/Q-depleted PSII from spinach, the = 4.1 EPR signal was detected. These results show that formation of the high-spin S state of the manganese cluster is regulated by the extrinsic proteins through a charge located near the Mn4 atom in the MnCaO cluster but is independent of the intrinsic proteins. The shift to the ∼ 5 state is caused by tilting of the -axis in the Mn4 coordinates through hydrogen bonds or external divalent cations. The structural modification may allow insertion of an oxygen atom during the S-to-S transition.
采用菠菜、 和 中的光系统 II（PSII）研究了高自旋 S 态。在 PSII 中除去外向蛋白后，在这两种物质中均未检测到高自旋电子顺磁共振（EPR）信号，而在高浓度 Ca 的存在下，所有物质均显示出约 5 个信号，而不是多线信号。在完整的 PSII 和菠菜的 PsbP/Q 耗尽 PSII 中，检测到 = 4.1 EPR 信号。这些结果表明，锰簇的高自旋 S 态的形成受到通过 Mn4 原子附近的电荷调节，通过外向蛋白位于 MnCaO 簇中，但与内在蛋白无关。通过氢键或外部二价阳离子，向 ～ 5 态的转变是由于 Mn4 坐标中的 -轴倾斜引起的。这种结构修饰可能允许在 S 到 S 转变期间插入一个氧原子。
