Department of Environmental Science and Technology , Cyprus University of Technology , 30 Archbishop Kyprianou Street , 3603 , Limassol , Cyprus.
Department of Physics & Earth Sciences , Jacobs University Bremen , Campus Ring 1 , 28759 Bremen , Germany.
J Phys Chem B. 2019 Nov 14;123(45):9609-9615. doi: 10.1021/acs.jpcb.9b09767. Epub 2019 Nov 1.
The allosteric regulation of protein function proves important in many life-sustaining processes. In plant photosynthesis, LHCII, the major antenna complex of Photosystem II, employs a delicate switch between light harvesting and photoprotective modes. The switch is triggered by an enlarged pH gradient (ΔpH) across the thylakoid membranes. Using molecular simulations and quantum calculations, we show that ΔpH can tune the light-harvesting potential of the antenna via allosteric regulation of the excitonic coupling in chlorophyll-carotenoid pairs. To this end, we propose how the LHCII excited state lifetime is coupled to the environmental conditions. In line with experimental findings, our theoretical model provides crucial evidence toward the elucidation of the photoprotective switch of higher plants at an all-atom resolution.
蛋白质功能的变构调节在许多维持生命的过程中证明是重要的。在植物光合作用中，LHCII 是光系统 II 的主要天线复合物，它在光捕获和光保护模式之间采用微妙的开关。该开关由类囊体膜上扩大的 pH 梯度（ΔpH）触发。我们使用分子模拟和量子计算表明，ΔpH 可以通过变构调节叶绿素-类胡萝卜素对中的激子耦合来调节天线的光捕获势。为此，我们提出了 LHCII 激发态寿命如何与环境条件耦合。与实验结果一致，我们的理论模型为阐明高等植物的光保护开关提供了至关重要的证据，达到了全原子分辨率。
