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Li A, You T, Pang X, Wang Y, Tian L, Li X, Liu Z. Structural basis for an early stage of the photosystem II repair cycle in Chlamydomonas reinhardtii. Nat Commun 2024; 15:5211. [PMID: 38890314 PMCID: PMC11189392 DOI: 10.1038/s41467-024-49532-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 06/10/2024] [Indexed: 06/20/2024] Open
Abstract
Photosystem II (PSII) catalyzes water oxidation and plastoquinone reduction by utilizing light energy. It is highly susceptible to photodamage under high-light conditions and the damaged PSII needs to be restored through a process known as the PSII repair cycle. The detailed molecular mechanism underlying the PSII repair process remains mostly elusive. Here, we report biochemical and structural features of a PSII-repair intermediate complex, likely arrested at an early stage of the PSII repair process in the green alga Chlamydomonas reinhardtii. The complex contains three protein factors associated with a damaged PSII core, namely Thylakoid Enriched Factor 14 (TEF14), Photosystem II Repair Factor 1 (PRF1), and Photosystem II Repair Factor 2 (PRF2). TEF14, PRF1 and PRF2 may facilitate the release of the manganese-stabilizing protein PsbO, disassembly of peripheral light-harvesting complexes from PSII and blockage of the QB site, respectively. Moreover, an α-tocopherol quinone molecule is located adjacent to the heme group of cytochrome b559, potentially fulfilling a photoprotective role by preventing the generation of reactive oxygen species.
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Affiliation(s)
- Anjie Li
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Tingting You
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, 310024, China
| | - Xiaojie Pang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Yidi Wang
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Lijin Tian
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xiaobo Li
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, 310024, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, 310024, China.
| | - Zhenfeng Liu
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China.
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STN7 Kinase Is Essential for Arabidopsis thaliana Fitness under Prolonged Darkness but Not under Dark-Chilling Conditions. Int J Mol Sci 2022; 23:ijms23094531. [PMID: 35562922 PMCID: PMC9100030 DOI: 10.3390/ijms23094531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/11/2022] [Accepted: 04/17/2022] [Indexed: 02/04/2023] Open
Abstract
Reversible phosphorylation of photosystem II light harvesting complexes (LHCII) is a well-established protective mechanism enabling efficient response to changing light conditions. However, changes in LHCII phosphorylation were also observed in response to abiotic stress regardless of photoperiod. This study aimed to investigate the impact of dark-chilling on LHCII phosphorylation pattern in chilling-tolerant Arabidopsis thaliana and to check whether the disturbed LHCII phosphorylation process will impact the response of Arabidopsis to the dark-chilling conditions. We analyzed the pattern of LHCII phosphorylation, the organization of chlorophyll–protein complexes, and the level of chilling tolerance by combining biochemical and spectroscopy techniques under dark-chilling and dark conditions in Arabidopsis mutants with disrupted LHCII phosphorylation. Our results show that during dark-chilling, LHCII phosphorylation decreased in all examined plant lines and that no significant differences in dark-chilling response were registered in tested lines. Interestingly, after 24 h of darkness, a high increase in LHCII phosphorylation was observed, co-occurring with a significant FV/FM parameter decrease. The highest drop of FV/FM was detected in the stn7-1 line–mutant, where the LHCII is not phosphorylated, due to the lack of STN7 kinase. Our results imply that STN7 kinase activity is important for mitigating the adverse effects of prolonged darkness.
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Zhang AO, Cui ZH, Yu JL, Hu ZL, Ding R, Ren DM, Zhang LJ. Dissipation of excess excitation energy of the needle leaves in Pinus trees during cold winters. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2016; 60:1953-1960. [PMID: 27192998 PMCID: PMC5127873 DOI: 10.1007/s00484-016-1182-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 04/19/2016] [Accepted: 04/30/2016] [Indexed: 06/05/2023]
Abstract
Photooxidative damage to the needle leaves of evergreen trees results from the absorption of excess excitation energy. Efficient dissipation of this energy is essential to prevent photodamage. In this study, we determined the fluorescence transients, absorption spectra, chlorophyll contents, chlorophyll a/b ratios, and relative membrane permeabilities of needle leaves of Pinus koraiensis, Pinus tabulaeformis, and Pinus armandi in both cold winter and summer. We observed a dramatic decrease in the maximum fluorescence (F m) and substantial absorption of light energy in winter leaves of all three species. The F m decline was not correlated with a decrease in light absorption or with changes in chlorophyll content and chlorophyll a/b ratio. The results suggested that the winter leaves dissipated a large amount of excess energy as heat. Because the cold winter leaves had lost normal physiological function, the heat dissipation depended solely on changes in the photosystem II supercomplex rather than the xanthophyll cycle. These findings imply that more attention should be paid to heat dissipation via changes in the photosystem complex structure during the growing season.
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Affiliation(s)
- A O Zhang
- College of Biological Sciences and Technology, Shenyang Agricultural University, Shenyang, 110866, China
- College of Agronomy, Shenyang Agricultural University, Shenyang, 110866, China
| | - Zhen-Hai Cui
- College of Biological Sciences and Technology, Shenyang Agricultural University, Shenyang, 110866, China
- Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang, 110866, China
| | - Jia-Lin Yu
- College of Biological Sciences and Technology, Shenyang Agricultural University, Shenyang, 110866, China
| | - Zi-Ling Hu
- College of Biological Sciences and Technology, Shenyang Agricultural University, Shenyang, 110866, China
| | - Rui Ding
- College of Biological Sciences and Technology, Shenyang Agricultural University, Shenyang, 110866, China
- College of Agronomy, Shenyang Agricultural University, Shenyang, 110866, China
| | - Da-Ming Ren
- College of Biological Sciences and Technology, Shenyang Agricultural University, Shenyang, 110866, China.
| | - Li-Jun Zhang
- College of Biological Sciences and Technology, Shenyang Agricultural University, Shenyang, 110866, China.
- College of Agronomy, Shenyang Agricultural University, Shenyang, 110866, China.
- Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang, 110866, China.
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Long-term and short-term responses of the photosynthetic electron transport to fluctuating light. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 137:89-99. [PMID: 24776379 DOI: 10.1016/j.jphotobiol.2014.02.016] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 02/19/2014] [Accepted: 02/22/2014] [Indexed: 12/26/2022]
Abstract
Light energy absorbed by chloroplasts drives photosynthesis. When absorbed light is in excess, the thermal dissipation systems of excess energy are induced and the photosynthetic electron flow is regulated, both contributing to suppression of reactive oxygen species production and photodamages. Various regulation mechanisms of the photosynthetic electron flow and energy dissipation systems have been revealed. However, most of such knowledge has been obtained by the experiments conducted under controlled conditions with constant light, whereas natural light condition is drastically fluctuated. To understand photosynthesis in nature, we need to clarify not only the mechanisms that raise photosynthetic efficiency but those for photoprotection in fluctuating light. Although these mechanisms appear to be well balanced, regulatory mechanisms achieving the balance is little understood. Recently, some pioneering studies have provided new insight into the regulatory mechanisms in fluctuating light. In this review, firstly, the possible mechanisms involved in regulation of the photosynthetic electron flow in fluctuating light are presented. Next, we introduce some recent studies focusing on the photosynthetic electron flow in fluctuating light. Finally, we discuss how plants effectively cope with fluctuating light showing our recent results.
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