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Shen L, Gao Y, Tang K, Qi R, Fu L, Chen JH, Wang W, Ma X, Li P, Chen M, Kuang T, Zhang X, Shen JR, Wang P, Han G. Structure of a unique PSII-Pcb tetrameric megacomplex in a chlorophyll d-containing cyanobacterium. SCIENCE ADVANCES 2024; 10:eadk7140. [PMID: 38394197 PMCID: PMC10889353 DOI: 10.1126/sciadv.adk7140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/22/2024] [Indexed: 02/25/2024]
Abstract
Acaryochloris marina is a unique cyanobacterium using chlorophyll d (Chl d) as its major pigment and thus can use far-red light for photosynthesis. Photosystem II (PSII) of A. marina associates with a number of prochlorophyte Chl-binding (Pcb) proteins to act as the light-harvesting system. We report here the cryo-electron microscopic structure of a PSII-Pcb megacomplex from A. marina at a 3.6-angstrom overall resolution and a 3.3-angstrom local resolution. The megacomplex is organized as a tetramer consisting of two PSII core dimers flanked by sixteen symmetrically related Pcb proteins, with a total molecular weight of 1.9 megadaltons. The structure reveals the detailed organization of PSII core consisting of 15 known protein subunits and an unknown subunit, the assembly of 4 Pcb antennas within each PSII monomer, and possible pathways of energy transfer within the megacomplex, providing deep insights into energy transfer and dissipation mechanisms within the PSII-Pcb megacomplex involved in far-red light utilization.
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Affiliation(s)
- Liangliang Shen
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
| | - Yuanzhu Gao
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kailu Tang
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Ruxi Qi
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Lutang Fu
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jing-Hua Chen
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Wenda Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
| | - Xiaomin Ma
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Peiyao Li
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Min Chen
- School of Life and Environmental Science, Faculty of Science, University of Sydney, Sydney NSW 2006, Australia
| | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
| | - Xing Zhang
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Center of Cryo-Electron Microscopy, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Laboratory for System and Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou 311121, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
- Institute for Interdisciplinary Science, and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Peiyi Wang
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
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Hamaguchi T, Kawakami K, Shinzawa-Itoh K, Inoue-Kashino N, Itoh S, Ifuku K, Yamashita E, Maeda K, Yonekura K, Kashino Y. Structure of the far-red light utilizing photosystem I of Acaryochloris marina. Nat Commun 2021; 12:2333. [PMID: 33879791 PMCID: PMC8058080 DOI: 10.1038/s41467-021-22502-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 03/18/2021] [Indexed: 01/09/2023] Open
Abstract
Acaryochloris marina is one of the cyanobacterial species that can use far-red light to drive photochemical reactions for oxygenic photosynthesis. Here, we report the structure of A. marina photosystem I (PSI) reaction center, determined by cryo-electron microscopy at 2.58 Å resolution. The structure reveals an arrangement of electron carriers and light-harvesting pigments distinct from other type I reaction centers. The paired chlorophyll, or special pair (also referred to as P740 in this case), is a dimer of chlorophyll d and its epimer chlorophyll d'. The primary electron acceptor is pheophytin a, a metal-less chlorin. We show the architecture of this PSI reaction center is composed of 11 subunits and we identify key components that help explain how the low energy yield from far-red light is efficiently utilized for driving oxygenic photosynthesis.
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Affiliation(s)
- Tasuku Hamaguchi
- Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, Sayo, Hyogo, Japan
| | - Keisuke Kawakami
- Research Center for Artificial Photosynthesis (ReCAP), Osaka City University, Sumiyoshi-ku, Osaka, Japan.
- Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, Sayo, Hyogo, Japan.
| | | | | | - Shigeru Itoh
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Kentaro Ifuku
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Eiki Yamashita
- Laboratory of Supramolecular Crystallography, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Kou Maeda
- Graduate School of Life Science, University of Hyogo, Ako-gun, Hyogo, Japan
| | - Koji Yonekura
- Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, Sayo, Hyogo, Japan.
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aoba-ku, Sendai, Japan.
| | - Yasuhiro Kashino
- Graduate School of Life Science, University of Hyogo, Ako-gun, Hyogo, Japan.
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Sano Y, Endo K, Tomo T, Noguchi T. Modified molecular interactions of the pheophytin and plastoquinone electron acceptors in photosystem II of chlorophyll D-containing Acaryochloris marina as revealed by FTIR spectroscopy. PHOTOSYNTHESIS RESEARCH 2015; 125:105-114. [PMID: 25560630 DOI: 10.1007/s11120-014-0073-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/20/2014] [Indexed: 06/04/2023]
Abstract
Acaryochloris marina is a unique cyanobacterium that contains chlorophyll (Chl) d as a major pigment. Because Chl d has smaller excitation energy than Chl a used in ordinary photosynthetic organisms, the energetics of the photosystems of A. marina have been the subject of interest. It was previously shown that the redox potentials (E m's) of the redox-active pheophytin a (Pheo) and the primary plastoquinone electron acceptor (QA) in photosystem II (PSII) of A. marina are higher than those in Chl a-containing PSII, to compensate for the smaller excitation energy of Chl d (Allakhverdiev et al., Proc Natl Acad Sci USA 107: 3924-3929, 2010; ibid. 108: 8054-8058, 2011). To clarify the mechanisms of these E m increases, in this study, we have investigated the molecular interactions of Pheo and QA in PSII core complexes from A. marina using Fourier transform infrared (FTIR) spectroscopy. Light-induced FTIR difference spectra upon single reduction of Pheo and QA showed that spectral features in the regions of the keto and ester C=O stretches and the chlorin ring vibrations of Pheo and in the CO/CC stretching region of the Q A (-) semiquinone anion in A. marina are significantly different from those of the corresponding spectra in Chl a-containing cyanobacteria. These observations indicate that the molecular interactions, including the hydrogen bond interactions at the C=O groups, of these cofactors are modified in their binding sites of PSII proteins. From these results, along with the sequence information of the D1 and D2 proteins, it is suggested that A. marina tunes the E m's of Pheo and QA by altering nearby hydrogen bond networks to modify the structures of the binding pockets of these cofactors.
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Affiliation(s)
- Yuko Sano
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
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