Orbital tuning of electron donor in photosystem II: A combined photo-CIDNP MAS NMR and theoretical study

植物光系统II （PS2）的光合反应中心（RC）允许光驱动电子转移（ET），量子效率接近单位。氧化电位高达1.4V，是水氧化所必需的，是生物自然界中最高的。PS2 RCs中的辅因子排列与紫色细菌的RCs有很强的相似性，但其作用机制却有明显的区别。异常高氧化还原电位的起源，轨道结构和蛋白质基质的作用仍未完全了解。这里我们的目的是了解控制轨道能量的因素。将采用先进的光化学诱导动态核极化（photocidnp）魔角自旋（MAS）核磁共振方法对辅助因子及其环境进行原子分辨率研究。将获得局部电子结构和局部迁移率。在Kohn-Sham和子系统DFT变体中，实验结果将与采用密度泛函理论（DFT）方法的理论建模密切合作进行解释。电子结构和控制的概念将启发人工光合作用。

The photosynthetic reaction center (RC) of Photosystem II (PS2) of plants allows for light-driven electron transfer (ET) with quantum efficiency close to unit. The oxidation potential of up to 1.4V, necessary for water oxidation, is the highest in living nature. The cofactor arrangement in the PS2 RC shows a strong similarity to that found in bacterial RCs of purple bacteria but the operational mechanism is clearly distinguished. The origin of the exceptional high redox potential, the orbital architecture and the role of the protein matrix are still not entirely understood. Here we aim to understand the factors controlling orbital energies. Advanced photochemically induced dynamic nuclear polarization (photo-CIDNP) magic-angle spinning (MAS) NMR methods will be applied to study the cofactors and their environment with atomic resolution. Local electronic structures and local mobility will be obtained. Experimental results will be interpreted in close collaboration with theoretical modelling by methods employing density functional theory (DFT), both in the Kohn-Sham and in the subsystem DFT variant. Concepts on the electronic architecture and control will inspire artificial photosynthesis.