School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371.
Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands.
Sci Adv. 2024 Feb 23;10(8):eadh0911. doi: 10.1126/sciadv.adh0911.
Photosystem II (PSII) is an integral part of the photosynthesis machinery, in which several light-harvesting complexes rely on inter-complex excitonic energy transfer (EET) processes to channel energy to the reaction center. In this paper, we report on a direct observation of the inter-complex EET in a minimal PSII supercomplex from plants, containing the trimeric light-harvesting complex II (LHCII), the monomeric light-harvesting complex CP26, and the monomeric PSII core complex. Using two-dimensional (2D) electronic spectroscopy, we measure an inter-complex EET timescale of 50 picoseconds for excitations from the LHCII-CP26 peripheral antenna to the PSII core. The 2D electronic spectra also reveal that the transfer timescale is nearly constant over the pump spectrum of 600 to 700 nanometers. Structure-based calculations reveal the contribution of each antenna complex to the measured inter-complex EET time. These results provide a step in elucidating the full inter-complex energy transfer network of the PSII machinery.
光系统 II（PSII）是光合作用机制的一个组成部分，其中几个光捕获复合物依赖于复合物间激子能量转移（EET）过程将能量传递到反应中心。在本文中，我们报告了来自植物的最小 PSII 超复合物中复合物间 EET 的直接观察结果，该超复合物包含三聚体光捕获复合物 II（LHCII）、单体光捕获复合物 CP26 和单体 PSII 核心复合物。我们使用二维（2D）电子光谱，测量了从 LHCII-CP26 外围天线到 PSII 核心的激发的复合物间 EET 时间尺度为 50 皮秒。2D 电子光谱还表明，转移时间尺度在 600 到 700 纳米的泵浦光谱范围内几乎是恒定的。基于结构的计算揭示了每个天线复合物对测量的复合物间 EET 时间的贡献。这些结果为阐明 PSII 机制的完整复合物间能量转移网络迈出了一步。
