J Integr Plant Biol.

• Research Article •    

Assembly mechanism of PSII-LHCII array from higher plants

Jianghao Wu1†, Cang Wu2†, Shuaijiabin Chen2,3†, Chao Huang1, Quan Wen3, Weijun Lin1, Chao Wang1, Dexian Han1, Dandan Lu1, Xiumei Xu1, Jun Gao3*, Sen‐Fang Sui2,4* and Lixin Zhang1*   

  1. 1. State Key Laboratory of Crop Stress Adaptation and Improvement, The Zhongzhou Laboratory for Integrative Biology, Henan KeyLaboratory of Synthetic Biology and Biomanufacturing, School of Life Sciences, Henan University, Kaifeng 475004, China

    2. School of Life Science, Southern University of Science and Technology, Shenzhen 518055, China

    3. Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China

    4. State State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing FrontierResearch Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China

    These authors contributed equally to this work.

    *Correspondences: Jun Gao (gaojun@mail.hzau.edu.cn); Sen‐Fang Sui (suisf@mail.tsinghua.edu.cn); Lixin Zhang (zhanglixin@henu.edu.cn,Dr. Zhang is fully responsible for the distribution of all materials associated with this article)

  • Received:2025-05-19 Accepted:2025-08-19 Online:2025-10-16
  • Supported by:
    This work was supported by the National Key Research and Development Program of China (2020YFA0907600),the National Natural Science Foundation of China (U2004204,32271245, 32241030, and 21873034), the Central Plains Scholar (234000510005), the 111 Project (#D16014), and the Fundamental Research Funds for the Central Universities (2662024XXPY003 and 2662023XXPY006).

Abstract: Photosystem II (PSII) comprises reaction centers and light-harvesting complexes of the major and minor antennas, forming diverse supercomplexes with varying antenna sizes and are organized as PSII arrays in grana thylakoids to respond to fluctuating light. However, the assembly mechanism of PSII arrays, excitation energy transfer and its regulation mechanisms in vascular plants remain poorly understood. Here, we report the cryo-electron microscopy structures of a 1.4-MDa PSII-LHCII (light-harvesting complex II) dimer and a 2.8-MDa tetramer, and present an initial model of hexamer from Arabidopsis. Structural and genetic analyses reveals that the tetramer is formed by two C2S2M2 dimers arranged side by side through interactions between CP26/PsbZ and moderate (M)-LHCII within PSII arrays in the grana thylakoid. Furthermore, conformational changes of M-LHCII and CP24 facilitate the assembly transition from dimer to tetramer/hexamer. Chlorophyll rearrangement, supported by computational calculations and spectral analysis, suggests enhanced energy transfer efficiency in the tetramer compared to the dimer. Therefore, our findings provide new insights into the dynamic assembly and excitation energy redistribution within PSII arrays in higher plants.

Key words: assembly, light acclimation, photosynthesis, PSIIarray

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