Department of Biochemistry, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Nat Plants. 2017 Mar 1;3:17014. doi: 10.1038/nplants.2017.14.
Four elaborate membrane complexes carry out the light reaction of oxygenic photosynthesis. Photosystem I (PSI) is one of two large reaction centres responsible for converting light photons into the chemical energy needed to sustain life. In the thylakoid membranes of plants, PSI is found together with its integral light-harvesting antenna, light-harvesting complex I (LHCI), in a membrane supercomplex containing hundreds of light-harvesting pigments. Here, we report the crystal structure of plant PSI-LHCI at 2.6 Å resolution. The structure reveals the configuration of PsaK, a core subunit important for state transitions in plants, a conserved network of water molecules surrounding the electron transfer centres and an elaborate structure of lipids bridging PSI and its LHCI antenna. We discuss the implications of the structure for energy transfer and the evolution of PSI.
四个精心设计的膜复合物执行产氧光合作用的光反应。光系统 I（PSI）是两个负责将光量子转化为维持生命所需的化学能量的大型反应中心之一。在植物的类囊体膜中，PSI 与它的完整的光捕获天线——光捕获复合物 I（LHCI）一起存在于一个包含数百个光捕获色素的膜超复合物中。在这里，我们报告了植物 PSI-LHCI 在 2.6Å 分辨率下的晶体结构。该结构揭示了 PsaK 的构象，PsaK 是植物状态转变中重要的核心亚基，一个围绕电子转移中心的水分子保守网络，以及一个精心设计的将 PSI 和它的 LHCI 天线桥接的脂类结构。我们讨论了结构对能量转移和 PSI 进化的影响。
