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Li Z, Li S, Chen L, Sun T, Zhang W. Fast-growing cyanobacterial chassis for synthetic biology application. Crit Rev Biotechnol 2024; 44:414-428. [PMID: 36842999 DOI: 10.1080/07388551.2023.2166455] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 11/19/2022] [Accepted: 12/28/2022] [Indexed: 02/28/2023]
Abstract
Carbon neutrality by 2050 has become one of the most urgent challenges the world faces today. To address the issue, it is necessary to develop and promote new technologies related with CO2 recycling. Cyanobacteria are the only prokaryotes performing oxygenic photosynthesis, capable of fixing CO2 into biomass under sunlight and serving as one of the most important primary producers on earth. Notably, recent progress on synthetic biology has led to utilizing model cyanobacteria such as Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 as chassis for "light-driven autotrophic cell factories" to produce several dozens of biofuels and various fine chemicals directly from CO2. However, due to the slow growth rate and low biomass accumulation in the current chassis, the productivity for most products is still lower than the threshold necessary for large-scale commercial application, raising the importance of developing high-efficiency cyanobacterial chassis with fast growth and/or higher biomass accumulation capabilities. In this article, we critically reviewed recent progresses on identification, systems biology analysis, and engineering of fast-growing cyanobacterial chassis. Specifically, fast-growing cyanobacteria identified in recent years, such as S. elongatus UTEX 2973, S. elongatus PCC 11801, S. elongatus PCC 11802 and Synechococcus sp. PCC 11901 was comparatively analyzed. In addition, the progresses on their recent application in converting CO2 into chemicals, and genetic toolboxes developed for these new cyanobacterial chassis were discussed. Finally, the article provides insights into future challenges and perspectives on the synthetic biology application of cyanobacterial chassis.
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Affiliation(s)
- Zhixiang Li
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, P.R. China
| | - Shubin Li
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, P.R. China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, P.R. China
| | - Tao Sun
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, P.R. China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin, P.R. China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, P.R. China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin, P.R. China
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Li W, Guo J, Han X, Da X, Wang K, Zhao H, Huang ST, Li B, He H, Jiang R, Zhou S, Yan P, Chen T, He Y, Xu J, Liu Y, Wu Y, Shou H, Wu Z, Mao C, Mo X. A novel protein domain is important for photosystem II complex assembly and photoautotrophic growth in angiosperms. MOLECULAR PLANT 2023; 16:374-392. [PMID: 36566350 DOI: 10.1016/j.molp.2022.12.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 11/24/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Photosystem II (PSII) is a multi-subunit protein complex of the photosynthetic electron transport chain that is vital to photosynthesis. Although the structure, composition, and function of PSII have been extensively studied, its biogenesis mechanism remains less understood. Thylakoid rhodanese-like (TROL) provides an anchor for leaf-type ferredoxin:NADP+ oxidoreductase. Here, we report the chacterizaton of a second type of TROL protein, TROL2, encoded by seed plant genomes whose function has not previously been reported. We show that TROL2 is a PSII assembly cofactor with essential roles in the establishment of photoautotrophy. TROL2 contains a 45-amino-acid domain, termed the chlorotic lethal seedling (CLS) domain, that is both necessary and sufficient for TROL2 function in PSII assembly and photoautotrophic growth. Phylogenetic analyses suggest that TROL2 may have arisen from ancestral TROL1 via gene duplication before the emergence of seed plants and acquired the CLS domain via evolution of the sequence encoding its N-terminal portion. We further reveal that TROL2 (or CLS) forms an assembly cofactor complex with the intrinsic thylakoid membrane protein LOW PSII ACCUMULATION2 and interacts with small PSII subunits to facilitate PSII complex assembly. Collectively, our study not only shows that TROL2 (CLS) is essential for photoautotrophy in angiosperms but also reveals its mechanistic role in PSII complex assembly, shedding light on the molecular and evolutionary mechanisms of photosynthetic complex assemblyin angiosperms.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Jiangfan Guo
- College of Life Science, Shaanxi Normal University, Xi'an, Shaanxi Province 710062, PR China
| | - Xue Han
- School of Advanced Agricultural Sciences and School of Life Sciences, State Key Laboratory of Protein and Plant Gene Research, Peking University, Beijing 100871, China; Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Weifang, Shandong 261000, China
| | - Xiaowen Da
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Kai Wang
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Hongfei Zhao
- College of Urban Construction, Zhejiang Shuren University, Hangzhou 310015, PR China
| | - Shi-Tang Huang
- School of Life Sciences, Peking University, Beijing 100871, PR China
| | - Bosheng Li
- Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Weifang, Shandong 261000, China
| | - Hang He
- School of Advanced Agricultural Sciences and School of Life Sciences, State Key Laboratory of Protein and Plant Gene Research, Peking University, Beijing 100871, China; Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Weifang, Shandong 261000, China
| | - Ruirui Jiang
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Shichen Zhou
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Peng Yan
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Tao Chen
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Yi He
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin'an, Hangzhou 311300, PR China
| | - Jiming Xu
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Yu Liu
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Yunrong Wu
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Huixia Shou
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Zhongchang Wu
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Chuanzao Mao
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China
| | - Xiaorong Mo
- State Key Laboratory of Plant Environmental Resilience, College of Life Science, Zhejiang University, Hangzhou 310058, PR China.
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Structure of a C 2S 2M 2N 2-type PSII-LHCII supercomplex from the green alga Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2019; 116:21246-21255. [PMID: 31570614 DOI: 10.1073/pnas.1912462116] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Photosystem II (PSII) in the thylakoid membranes of plants, algae, and cyanobacteria catalyzes light-induced oxidation of water by which light energy is converted to chemical energy and molecular oxygen is produced. In higher plants and most eukaryotic algae, the PSII core is surrounded by variable numbers of light-harvesting antenna complex II (LHCII), forming a PSII-LHCII supercomplex. In order to harvest energy efficiently at low-light-intensity conditions under water, a complete PSII-LHCII supercomplex (C2S2M2N2) of the green alga Chlamydomonas reinhardtii (Cr) contains more antenna subunits and pigments than the dominant PSII-LHCII supercomplex (C2S2M2) of plants. The detailed structure and energy transfer pathway of the Cr-PSII-LHCII remain unknown. Here we report a cryoelectron microscopy structure of a complete, C2S2M2N2-type PSII-LHCII supercomplex from C. reinhardtii at 3.37-Å resolution. The results show that the Cr-C2S2M2N2 supercomplex is organized as a dimer, with 3 LHCII trimers, 1 CP26, and 1 CP29 peripheral antenna subunits surrounding each PSII core. The N-LHCII trimer partially occupies the position of CP24, which is present in the higher-plant PSII-LHCII but absent in the green alga. The M trimer is rotated relative to the corresponding M trimer in plant PSII-LHCII. In addition, some unique features were found in the green algal PSII core. The arrangement of a huge number of pigments allowed us to deduce possible energy transfer pathways from the peripheral antennae to the PSII core.
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Burton-Smith RN, Watanabe A, Tokutsu R, Song C, Murata K, Minagawa J. Structural determination of the large photosystem II-light-harvesting complex II supercomplex of Chlamydomonas reinhardtii using nonionic amphipol. J Biol Chem 2019; 294:15003-15013. [PMID: 31420447 DOI: 10.1074/jbc.ra119.009341] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/14/2019] [Indexed: 02/01/2023] Open
Abstract
In photosynthetic organisms, photosystem II (PSII) is a large membrane protein complex, consisting of a pair of core complexes surrounded by an array of variable numbers of light-harvesting complex (LHC) II proteins. Previously reported structures of the PSII-LHCII supercomplex of the green alga Chlamydomonas reinhardtii exhibit significant structural heterogeneity, but recently improved purification methods employing ionic amphipol A8-35 have enhanced supercomplex stability, providing opportunities for determining a more intact structure. Herein, we present a 5.8 Å cryo-EM map of the C. reinhardtii PSII-LHCII supercomplex containing six LHCII trimers (C2S2M2L2). Utilizing a newly developed nonionic amphipol-based purification and stabilizing method, we purified the largest photosynthetic supercomplex to the highest percentage of the intact configuration reported to date. We found that the interprotein distances within the light-harvesting complex array in the green algal photosystem are larger than those previously observed in higher plants, indicating that the potential route of energy transfer in the PSII-LHCII supercomplex in green algae may be altered. Interestingly, we also observed an asymmetric PSII-LHCII supercomplex structure comprising C2S2M1L1 in the same sample. Moreover, we found a new density adjacent to the PSII core complex, attributable to a single-transmembrane helix. It was previously unreported in the cryo-EM maps of PSII-LHCII supercomplexes from land plants.
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Affiliation(s)
- Raymond N Burton-Smith
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
| | - Akimasa Watanabe
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan.,Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
| | - Ryutaro Tokutsu
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan.,Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
| | - Chihong Song
- National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | - Kazuyoshi Murata
- National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan .,Department of Physiological Sciences, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
| | - Jun Minagawa
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan .,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan.,Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
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Jaiswal D, Sengupta A, Sohoni S, Sengupta S, Phadnavis AG, Pakrasi HB, Wangikar PP. Genome Features and Biochemical Characteristics of a Robust, Fast Growing and Naturally Transformable Cyanobacterium Synechococcus elongatus PCC 11801 Isolated from India. Sci Rep 2018; 8:16632. [PMID: 30413737 PMCID: PMC6226537 DOI: 10.1038/s41598-018-34872-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/26/2018] [Indexed: 01/09/2023] Open
Abstract
Cyanobacteria provide an interesting platform for biotechnological applications due to their efficient photoautotrophic growth, amenability to genetic engineering and the ability to grow on non-arable land. An ideal industrial strain of cyanobacteria would need to be fast growing and tolerant to high levels of temperature, light, carbon dioxide, salt and be naturally transformable. In this study, we report Synechococcus elongatus PCC 11801, a strain isolated from India that fulfills these requirements. The physiological and biochemical characteristics of PCC 11801 under carbon and light-limiting conditions were investigated. PCC 11801 shows a doubling time of 2.3 h, that is the fastest growth for any cyanobacteria reported so far under ambient CO2 conditions. Genome sequence of PCC 11801 shows genome identity of ~83% with its closest neighbors Synechococcus elongatus PCC 7942 and Synechococcus elongatus UTEX 2973. The unique attributes of PCC 11801 genome are discussed in light of the physiological characteristics that are needed in an industrial strain. The genome of PCC 11801 shows several genes that do not have homologs in neighbor strains PCC 7942 and UTEX 2973, some of which may be responsible for adaptation to various abiotic stresses. The remarkably fast growth rate of PCC 11801 coupled with its robustness and ease of genetic transformation makes it an ideal candidate for the photosynthetic production of fuels and chemicals.
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Affiliation(s)
- Damini Jaiswal
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Annesha Sengupta
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Sujata Sohoni
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Shinjinee Sengupta
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.,DBT-PAN IIT Centre for Bioenergy, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Ambarish G Phadnavis
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO, 63130, USA.,Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, 63130, USA
| | - Pramod P Wangikar
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. .,DBT-PAN IIT Centre for Bioenergy, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. .,Wadhwani Research Centre for Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
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Shi LX, Hall M, Funk C, Schröder WP. Photosystem II, a growing complex: updates on newly discovered components and low molecular mass proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:13-25. [PMID: 21907181 DOI: 10.1016/j.bbabio.2011.08.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 08/19/2011] [Accepted: 08/23/2011] [Indexed: 12/12/2022]
Abstract
Photosystem II is a unique complex capable of absorbing light and splitting water. The complex has been thoroughly studied and to date there are more than 40 proteins identified, which bind to the complex either stably or transiently. Another special feature of this complex is the unusually high content of low molecular mass proteins that represent more than half of the proteins. In this review we summarize the recent findings on the low molecular mass proteins (<15kDa) and present an overview of the newly identified components as well. We have also performed co-expression analysis of the genes encoding PSII proteins to see if the low molecular mass proteins form a specific sub-group within the Photosystem II complex. Interestingly we found that the chloroplast-localized genes encoding PSII proteins display a different response to environmental and stress conditions compared to the nuclear localized genes. This article is part of a Special Issue entitled: Photosystem II.
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Affiliation(s)
- Lan-Xin Shi
- Department of Plant Biology, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
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Inoue-Kashino N, Kashino Y, Takahashi Y. Psb30 is a photosystem II reaction center subunit and is required for optimal growth in high light in Chlamydomonas reinhardtii. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:220-8. [DOI: 10.1016/j.jphotobiol.2011.01.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 01/26/2011] [Accepted: 01/31/2011] [Indexed: 11/26/2022]
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Inoue-Kashino N, Kashino Y, Orii H, Satoh K, Terashima I, Pakrasi HB. S4 protein Sll1252 is necessary for energy balancing in photosynthetic electron transport in Synechocystis sp. PCC 6803. Biochemistry 2010; 50:329-39. [PMID: 21141807 DOI: 10.1021/bi101077e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Sll1252 was identified as a novel protein in photosystem II complexes from Synechocystis sp. PCC 6803. To investigate the function of Sll1252, the corresponding gene, sll1252, was deleted in Synechocystis 6803. Despite the homology of Sll1252 to YlmH, which functions in the cell division machinery in Streptococcus, the growth rate and cell morphology of the mutant were not affected in normal growth medium. Instead, it seems that cells lacking this polypeptide have increased sensitivity to Cl(-) depletion. The growth and oxygen evolving activity of the mutant cells was highly suppressed compared with those of wild-type cells when Cl(-) and/or Ca(2+) was depleted from the medium. Recovery of photosystem II from photoinhibition was suppressed in the mutant. Despite the defects in photosystem II, in the light, the acceptor side of photosystem II was more reduced and the donor side of photosystem I was more oxidized compared with wild-type cells, suggesting that functional impairments were also present in cytochrome b(6)/f complexes. The amounts of cytochrome c(550) and cytochrome f were smaller in the mutant in the Ca(2+)- and Cl(-)-depleted medium. Furthermore, the amount of IsiA protein was increased in the mutant, especially in the Cl(-)-depleted medium, indicating that the mutant cells perceive environmental stress to be greater than it is. The amount of accompanying cytochrome c(550) in purified photosystem II complexes was also smaller in the mutant. Overall, the Sll1252 protein appears to be closely related to redox sensing of the plastoquinone pool to balance the photosynthetic electron flow and the ability to cope with global environmental stresses.
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Sugiura M, Harada S, Manabe T, Hayashi H, Kashino Y, Boussac A. Psb30 contributes to structurally stabilise the Photosystem II complex in the thermophilic cyanobacterium Thermosynechococcus elongatus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1546-54. [DOI: 10.1016/j.bbabio.2010.03.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 03/23/2010] [Accepted: 03/24/2010] [Indexed: 11/16/2022]
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Nixon PJ, Michoux F, Yu J, Boehm M, Komenda J. Recent advances in understanding the assembly and repair of photosystem II. ANNALS OF BOTANY 2010; 106:1-16. [PMID: 20338950 PMCID: PMC2889791 DOI: 10.1093/aob/mcq059] [Citation(s) in RCA: 390] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/01/2010] [Accepted: 02/09/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND Photosystem II (PSII) is the light-driven water:plastoquinone oxidoreductase of oxygenic photosynthesis and is found in the thylakoid membrane of chloroplasts and cyanobacteria. Considerable attention is focused on how PSII is assembled in vivo and how it is repaired following irreversible damage by visible light (so-called photoinhibition). Understanding these processes might lead to the development of plants with improved growth characteristics especially under conditions of abiotic stress. SCOPE Here we summarize recent results on the assembly and repair of PSII in cyanobacteria, which are excellent model organisms to study higher plant photosynthesis. CONCLUSIONS Assembly of PSII is highly co-ordinated and proceeds through a number of distinct assembly intermediates. Associated with these assembly complexes are proteins that are not found in the final functional PSII complex. Structural information and possible functions are beginning to emerge for several of these 'assembly' factors, notably Ycf48/Hcf136, Psb27 and Psb28. A number of other auxiliary proteins have been identified that appear to have evolved since the divergence of chloroplasts and cyanobacteria. The repair of PSII involves partial disassembly of the damaged complex, the selective replacement of the damaged sub-unit (predominantly the D1 sub-unit) by a newly synthesized copy, and reassembly. It is likely that chlorophyll released during the repair process is temporarily stored by small CAB-like proteins (SCPs). A model is proposed in which damaged D1 is removed in Synechocystis sp. PCC 6803 by a hetero-oligomeric complex composed of two different types of FtsH sub-unit (FtsH2 and FtsH3), with degradation proceeding from the N-terminus of D1 in a highly processive reaction. It is postulated that a similar mechanism of D1 degradation also operates in chloroplasts. Deg proteases are not required for D1 degradation in Synechocystis 6803 but members of this protease family might play a supplementary role in D1 degradation in chloroplasts under extreme conditions.
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Affiliation(s)
- Peter J Nixon
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
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Guskov A, Gabdulkhakov A, Broser M, Glöckner C, Hellmich J, Kern J, Frank J, Müh F, Saenger W, Zouni A. Recent Progress in the Crystallographic Studies of Photosystem II. Chemphyschem 2010; 11:1160-71. [DOI: 10.1002/cphc.200900901] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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12
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Takasaka K, Iwai M, Umena Y, Kawakami K, Ohmori Y, Ikeuchi M, Takahashi Y, Kamiya N, Shen JR. Structural and functional studies on Ycf12 (Psb30) and PsbZ-deletion mutants from a thermophilic cyanobacterium. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:278-84. [DOI: 10.1016/j.bbabio.2009.11.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 11/02/2009] [Accepted: 11/06/2009] [Indexed: 11/17/2022]
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