Structures and organizations of PSI-AcpPCI supercomplexes from red tidal and coral symbiotic photosynthetic dinoflagellates

• 成果类型: Article
• 署名作者: Li, Xiaoyi; Li, Zhenhua; Wang, Fangfang; Zhao, Songhao; Xu, Caizhe; Mao, Zhiyuan; Duan, Jialin; Feng, Yue; Yang, Yang; Shen, Lili; Wang, Guanglei; Yang, Yanyan; Yu, Long-Jiang; Sang, Min; Han, Guangye; Wang, Xuchu; Kuang, Tingyun; Shen, Jian-Ren; Wang, Wenda
• 署名单位: Chinese Academy of Sciences; Institute of Botany, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Chinese Academy of Sciences; Tsinghua University; Hainan Normal University; Guizhou University; Okayama University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13516
• DOI: 10.1073/pnas.2315476121
• 发表日期: 2024-02-13
• 关键词: algal photosystem-i; fucoxanthin-chlorophyll-proteins; energy-transfer pathways; light; EVOLUTION; amphidinium; complex; genome

摘要

Marine photosynthetic dinoflagellates are a group of successful phytoplankton that can form red tides in the ocean and also symbiosis with corals. These features are closely related to the photosynthetic properties of dinoflagellates. We report here three structures of photosystem I (PSI)-chlorophylls (Chls) a/c- peridinin protein complex (PSI- AcpPCI) from two species of dinoflagellates by single- particle cryoelectron microscopy. The crucial PsaA/B subunits of a red tidal dinoflagellate Amphidinium carterae are remarkably smaller and hence losing over 20 pigment- binding sites, whereas its PsaD/ F/I/J/L/M/R subunits are larger and coordinate some additional pigment sites compared to other eukaryotic photosynthetic organisms, which may compensate for the smaller PsaA/B subunits. Similar modifications are observed in a coral symbiotic dinoflagellate Symbiodinium species, where two additional core proteins and fewer AcpPCIs are identified in the PSI-AcpPCI supercomplex. The antenna proteins AcpPCIs in dinoflagellates developed some loops and pigment sites as a result to accommodate the changed PSI core, therefore the structures of PSI-AcpPCI supercomplex of dinoflagellates reveal an unusual protein assembly pattern. A huge pigment network comprising Chls a and c and various carotenoids is revealed from the structural analysis, which provides the basis for our deeper understanding of the energy transfer and dissipation within the PSI-AcpPCI supercomplex, as well as the evolution of photosynthetic organisms.