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Wang S, Duo J, Wufuer R, Li W, Pan X. The Binding Ability of Mercury (Hg) to Photosystem I and II Explained the Difference in Its Toxicity on the Two Photosystems of Chlorella pyrenoidosa. TOXICS 2022; 10:455. [PMID: 36006134 PMCID: PMC9416214 DOI: 10.3390/toxics10080455] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Mercury (Hg) poses high toxicity to organisms including algae. Studies showed that the growth and photosynthesis of green algae such as Chlorella are vulnerable to Hg stress. However, the differences between the activities and tolerance of photosystem I and II (PSI and PSII) of green microalgae under Hg exposure are still little known. Responses of quantum yields and electron transport rates (ETRs) of PSI and PSII of Chlorella pyrenoidosa to 0.05−1 mg/L Hg2+ were simultaneously measured for the first time by using the Dual-PAM-100 system. The photosystems were isolated to analyze the characteristics of toxicity of Hg during the binding process. The inhibition of Hg2+ on growth and photosystems was found. PSII was more seriously affected by Hg2+ than PSI. After Hg2+ exposure, the photochemical quantum yield of PSII [Y(II)] decreased with the increase in non-photochemical fluorescence quenching [Y(NO) and Y(NPQ)]. The toxic effects of Hg on the photochemical quantum yield and ETR in PSI were lower than those of PSII. The stimulation of cyclic electron yield (CEF) was essential for the stability and protection of PSI under Hg stress and played an important role in the induction of non-photochemical quenching (NPQ). The results showed a strong combination ability of Hg ions and photosystem particles. The number of the binding sites (n) of Hg on PSII was more than that of PSI, which may explain the different toxicity of Hg on PSII and PSI.
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Affiliation(s)
- Shuzhi Wang
- National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi 830011, China
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
| | - Jia Duo
- National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi 830011, China
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
| | - Rehemanjiang Wufuer
- National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi 830011, China
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
| | - Wenfeng Li
- National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi 830011, China
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
| | - Xiangliang Pan
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
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2
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Macromolecular conformational changes in photosystem II: interaction between structure and function. Biophys Rev 2022; 14:871-886. [DOI: 10.1007/s12551-022-00979-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 07/02/2022] [Indexed: 01/08/2023] Open
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Chiu YF, Chu HA. New Structural and Mechanistic Insights Into Functional Roles of Cytochrome b 559 in Photosystem II. FRONTIERS IN PLANT SCIENCE 2022; 13:914922. [PMID: 35755639 PMCID: PMC9214863 DOI: 10.3389/fpls.2022.914922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 04/27/2022] [Indexed: 06/15/2023]
Abstract
Cytochrome (Cyt) b 559 is a key component of the photosystem II (PSII) complex for its assembly and proper function. Previous studies have suggested that Cytb 559 has functional roles in early assembly of PSII and in secondary electron transfer pathways that protect PSII against photoinhibition. In addition, the Cytb 559 in various PSII preparations exhibited multiple different redox potential forms. However, the precise functional roles of Cytb 559 in PSII remain unclear. Recent site-directed mutagenesis studies combined with functional genomics and biochemical analysis, as well as high-resolution x-ray crystallography and cryo-electron microscopy studies on native, inactive, and assembly intermediates of PSII have provided important new structural and mechanistic insights into the functional roles of Cytb 559. This mini-review gives an overview of new exciting results and their significance for understanding the structural and functional roles of Cytb 559 in PSII.
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Chiu Y, Fu H, Skotnicová P, Lin K, Komenda J, Chu H. Tandem gene amplification restores photosystem II accumulation in cytochrome b 559 mutants of cyanobacteria. THE NEW PHYTOLOGIST 2022; 233:766-780. [PMID: 34625967 PMCID: PMC9297868 DOI: 10.1111/nph.17785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/30/2021] [Indexed: 05/11/2023]
Abstract
Cytochrome (Cyt) b559 is a key component of the photosystem II complex (PSII) that is essential for its proper functioning and assembly. Site-directed mutants of the model cyanobacterium Synechocystis sp. PCC6803 with mutated heme axial ligands of Cyt b559 have little PSII and are therefore unable to grow photoautotrophically. Here we describe two types of Synechocystis autotrophic transformants that retained the same mutations in Cyt b559 but are able to accumulate PSII and grow photoautotrophically. Whole-genome sequencing revealed that all of these autotrophic transformants carried a variable number of tandem repeats (from 5 to 15) of chromosomal segments containing the psbEFLJ operon. RNA-seq analysis showed greatly increased transcript levels of the psbEFLJ operon in these autotrophic transformants. Multiple copies of the psbEFLJ operon in these transformants were only maintained during autotrophic growth, while its copy numbers gradually decreased under photoheterotrophic conditions. Two-dimensional PAGE analysis of membrane proteins revealed a strong deficiency in PSII complexes in the Cyt b559 mutants that was reversed in the autotrophic transformants. These results illustrate how tandem gene amplification restores PSII accumulation and photoautotrophic growth in Cyt b559 mutants of cyanobacteria, and may serve as an important adaptive mechanism for cyanobacterial survival.
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Affiliation(s)
- Yi‐Fang Chiu
- Institute of Plant and Microbial BiologyAcademia SinicaTaipei11529Taiwan
| | - Han‐Yi Fu
- Institute of Plant and Microbial BiologyAcademia SinicaTaipei11529Taiwan
| | - Petra Skotnicová
- Laboratory of PhotosynthesisCentre AlgatechInstitute of Microbiology of the Czech Academy of SciencesTřeboň379 01Czech Republic
| | - Keng‐Min Lin
- Institute of Plant and Microbial BiologyAcademia SinicaTaipei11529Taiwan
| | - Josef Komenda
- Laboratory of PhotosynthesisCentre AlgatechInstitute of Microbiology of the Czech Academy of SciencesTřeboň379 01Czech Republic
| | - Hsiu‐An Chu
- Institute of Plant and Microbial BiologyAcademia SinicaTaipei11529Taiwan
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Endo K, Kobayashi K, Wang HT, Chu HA, Shen JR, Wada H. Site-directed mutagenesis of two amino acid residues in cytochrome b 559 α subunit that interact with a phosphatidylglycerol molecule (PG772) induces quinone-dependent inhibition of photosystem II activity. PHOTOSYNTHESIS RESEARCH 2019; 139:267-279. [PMID: 30039358 DOI: 10.1007/s11120-018-0555-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 07/07/2018] [Indexed: 06/08/2023]
Abstract
X-ray crystallographic analysis (1.9-Å resolution) of the cyanobacterial photosystem II (PSII) dimer showed the presence of five phosphatidylglycerol (PG) molecules per reaction center. One of the PG molecules, PG772, is located in the vicinity of the QB-binding site. To investigate the role of PG772 in PSII, we performed site-directed mutagenesis in the cytochrome (Cyt) b559 α subunit of Synechocystis sp. PCC 6803 to change two amino acids, Thr-5 and Ser-11, which interact with PG772. The photosynthetic activity of intact cells was slightly lower in all mutants than that of cells in the control strain; however, the oxygen-evolving PSII activity was decreased markedly in cells of mutants, as measured using artificial quinones (such as p-benzoquinone). Furthermore, electron transport from QA to QB was inhibited in mutants incubated with quinones, particularly under high-intensity light conditions. Lipid analysis of purified PSII showed approximately one PG molecule per reaction center, presumably PG772, was lost in the PSII dimer from the T5A and S11A mutants compared with that in the PSII dimer from the control strain. In addition, protein analysis of monomer and dimer showed decreased levels of PsbV and PsbU extrinsic proteins in the PSII monomer purified from T5A and S11A mutants. These results suggest that site-directed mutagenesis of Thr-5 and Ser-11, which presumably causes the loss of PG772, induces quinone-dependent inhibition of PSII activity under high-intensity light conditions and destabilizes the binding of extrinsic proteins to PSII.
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Affiliation(s)
- Kaichiro Endo
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8902, Japan
| | - Koichi Kobayashi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8902, Japan
| | - Hsing-Ting Wang
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei, 11529, Taiwan, Republic of China
| | - Hsiu-An Chu
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei, 11529, Taiwan, Republic of China
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka, Okayama, 700-8530, Japan
| | - Hajime Wada
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
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6
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Nakamura M, Boussac A, Sugiura M. Consequences of structural modifications in cytochrome b 559 on the electron acceptor side of Photosystem II. PHOTOSYNTHESIS RESEARCH 2019; 139:475-486. [PMID: 29779191 DOI: 10.1007/s11120-018-0521-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
Cytb559 in Photosystem II is a heterodimeric b-type cytochrome. The subunits, PsbE and PsbF, consist each in a membrane α-helix. Mutants were previously designed and studied in Thermosynechococcus elongatus (Sugiura et al., Biochim Biophys Acta 1847:276-285, 2015) either in which an axial histidine ligand of the haem-iron was substituted for a methionine, the PsbE/H23M mutant in which the haem was lacking, or in which the haem environment was modified, the PsbE/Y19F and PsbE/T26P mutants. All these mutants remained active showing that the haem has no structural role provided that PsbE and PsbF subunits are present. Here, we have carried on the characterization of these mutants. The following results were obtained: (i) the Y19F mutation hardly affect the Em of Cytb559, whereas the T26P mutation converts the haem into a form with a Em much below 0 mV (so low that it is likely not reducible by QB-) even in an active enzyme; (ii) in the PsbE/H23M mutant, and to a less extent in PsbE/T26P mutant, the electron transfer efficiency from QA- to QB is decreased; (iii) the lower Em of the QA/QA- couple in the PsbE/H23M mutant correlates with a higher production of singlet oxygen; (iv) the superoxide and/or hydroperoxide formation was not increased in the PsbE/H23M mutant lacking the haem, whereas it was significantly larger in the PsbE/T26P. These data are discussed in view of the literature to discriminate between structural and redox roles for the haem of Cytb559 in the production of reactive oxygen species.
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Affiliation(s)
- Makoto Nakamura
- Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Alain Boussac
- I2BC, CNRS UMR 9198, CEA Saclay, 91191, Gif-sur-Yvette, France
| | - Miwa Sugiura
- Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan.
- Proteo-Science Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan.
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7
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Tang C, Yang C, Yu H, Tian S, Huang X, Wang W, Cai P. Electromagnetic Radiation Disturbed the Photosynthesis of Microcystis aeruginosa at the Proteomics Level. Sci Rep 2018; 8:479. [PMID: 29323219 PMCID: PMC5764990 DOI: 10.1038/s41598-017-18953-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 12/19/2017] [Indexed: 11/09/2022] Open
Abstract
Photosynthesis of Microcystis aeruginosa under Electromagnetic Radiation (1.8 GHz, 40 V/m) was studied by using the proteomics. A total of 30 differentially expressed proteins, including 15 up-regulated and 15 down-regulated proteins, were obtained in this study. The differentially expressed proteins were significantly enriched in the photosynthesis pathway, in which the protein expression levels of photosystems II cytochrome b559 α subunit, cytochrome C550, PsbY, and F-type ATP synthase (a, b) decreased. Our results indicated that electromagnetic radiation altered the photosynthesis-related protein expression levels, and aimed at the function of photosynthetic pigments, photosystems II potential activity, photosynthetic electron transport process, and photosynthetic phosphorylation process of M. aeruginosa. Based on the above evidence, that photoreaction system may be deduced as a target of electromagnetic radiation on the photosynthesis in cyanobacteria; the photoreaction system of cyanobacteria is a hypothetical "shared target effector" that responds to light and electromagnetic radiation; moreover, electromagnetic radiation does not act on the functional proteins themselves but their expression processes.
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Affiliation(s)
- Chao Tang
- Physical Environment Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, P.R. China.,University of the Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, P.R. China.,Xiamen Key Laboratory of Physical Environment, 1799 Jimei Road, Xiamen, 361021, P.R. China
| | - Chuanjun Yang
- Physical Environment Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, P.R. China.,Xiamen Key Laboratory of Physical Environment, 1799 Jimei Road, Xiamen, 361021, P.R. China
| | - Hui Yu
- Physical Environment Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, P.R. China.,Xiamen Key Laboratory of Physical Environment, 1799 Jimei Road, Xiamen, 361021, P.R. China
| | - Shen Tian
- Physical Environment Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, P.R. China.,Xiamen Key Laboratory of Physical Environment, 1799 Jimei Road, Xiamen, 361021, P.R. China
| | - Xiaomei Huang
- Physical Environment Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, P.R. China.,University of the Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, P.R. China.,Xiamen Key Laboratory of Physical Environment, 1799 Jimei Road, Xiamen, 361021, P.R. China
| | - Weiyi Wang
- University of the Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, P.R. China.,Xiamen Key Laboratory of Physical Environment, 1799 Jimei Road, Xiamen, 361021, P.R. China
| | - Peng Cai
- Physical Environment Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, P.R. China. .,Xiamen Key Laboratory of Physical Environment, 1799 Jimei Road, Xiamen, 361021, P.R. China.
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8
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Yotsova EK, Stefanov MA, Dobrikova AG, Apostolova EL. Different sensitivities of photosystem II in green algae and cyanobacteria to phenylurea and phenol-type herbicides: effect on electron donor side. ACTA ACUST UNITED AC 2017; 72:315-324. [PMID: 28258977 DOI: 10.1515/znc-2016-0089] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 02/05/2017] [Indexed: 11/15/2022]
Abstract
Abstract
The effects of short-term treatment with phenylurea (DCMU, isoproturon) and phenol-type (ioxynil) herbicides on the green alga Chlorella kessleri and the cyanobacterium Synechocystis salina with different organizations of photosystem II (PSII) were investigated using pulse amplitude modulated (PAM) chlorophyll fluorescence and photosynthetic oxygen evolution measured by polarographic oxygen electrodes (Clark-type and Joliot-type). The photosynthetic oxygen evolution showed stronger inhibition than the PSII photochemistry. The effects of the studied herbicides on both algal and cyanobacterial cells decreased in the following order: DCMU>isoproturon>ioxynil. Furthermore, we observed that the number of blocked PSII centers increased significantly after DCMU treatment (204–250 times) and slightly after ioxynil treatment (19–35 times) in comparison with the control cells. This study suggests that the herbicides affect not only the acceptor side but also the donor side of PSII by modifications of the Mn cluster of the oxygen-evolving complex. We propose that one of the reasons for the different PSII inhibitions caused by herbicides is their influence, in different extents, on the kinetic parameters of the oxygen-evolving reactions (the initial S0−S1 state distribution, the number of blocked centers SB, the turnover time of Si states, misses and double hits). The relationship between the herbicide-induced inhibition and the changes in the kinetic parameters is discussed.
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Affiliation(s)
- Ekaterina K Yotsova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113, Bulgaria
| | - Martin A Stefanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113, Bulgaria
| | - Anelia G Dobrikova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113, Bulgaria
| | - Emilia L Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria, Tel: +359-2979-2621, Fax: +359-2971-2493
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Huang JY, Chiu YF, Ortega JM, Wang HT, Tseng TS, Ke SC, Roncel M, Chu HA. Mutations of Cytochrome b559 and PsbJ on and near the QC Site in Photosystem II Influence the Regulation of Short-Term Light Response and Photosynthetic Growth of the Cyanobacterium Synechocystis sp. PCC 6803. Biochemistry 2016; 55:2214-26. [DOI: 10.1021/acs.biochem.6b00133] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Jine-Yung Huang
- Institute
of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Fang Chiu
- Institute
of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - José M. Ortega
- Instituto
de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, 41092 Seville, Spain
| | - Hsing-Ting Wang
- Institute
of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Tien-Sheng Tseng
- Institute
of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Shyue-Chu Ke
- Department
of Physics, National Dong Hwa University, Hualien 97401, Taiwan
| | - Mercedes Roncel
- Instituto
de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, 41092 Seville, Spain
| | - Hsiu-An Chu
- Institute
of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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10
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Nishimura T, Nagao R, Noguchi T, Nield J, Sato F, Ifuku K. The N-terminal sequence of the extrinsic PsbP protein modulates the redox potential of Cyt b559 in photosystem II. Sci Rep 2016; 6:21490. [PMID: 26887804 PMCID: PMC4757834 DOI: 10.1038/srep21490] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/25/2016] [Indexed: 11/20/2022] Open
Abstract
The PsbP protein, an extrinsic subunit of photosystem II (PSII) in green plants, is known to induce a conformational change around the catalytic Mn4CaO5 cluster securing the binding of Ca2+ and Cl– in PSII. PsbP has multiple interactions with the membrane subunits of PSII, but how these affect the structure and function of PSII requires clarification. Here, we focus on the interactions between the N-terminal residues of PsbP and the α subunit of Cytochrome (Cyt) b559 (PsbE). A key observation was that a peptide fragment formed of the first N-terminal 15 residues of PsbP, ‘pN15’, was able to convert Cyt b559 into its HP form. Interestingly, addition of pN15 to NaCl-washed PSII membranes decreased PSII’s oxygen-evolving activity, even in the presence of saturating Ca2+ and Cl– ions. In fact, pN15 reversibly inhibited the S1 to S2 transition of the OEC in PSII. These data suggest that pN15 can modulate the redox property of Cyt b559 involved in the side-electron pathway in PSII. This potential change of Cyt b559, in the absence of the C-terminal domain of PsbP, however, would interfere with any electron donation from the Mn4CaO5 cluster, leading to the possibility that multiple interactions of PsbP, binding to PSII, have distinct roles in regulating electron transfer within PSII.
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Affiliation(s)
- Taishi Nishimura
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Ryo Nagao
- Graduate School of Science, Nagoya University, Aichi 464-8602, Japan
| | - Takumi Noguchi
- Graduate School of Science, Nagoya University, Aichi 464-8602, Japan
| | - Jon Nield
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Fumihiko Sato
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kentaro Ifuku
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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11
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Chu HA, Chiu YF. The Roles of Cytochrome b 559 in Assembly and Photoprotection of Photosystem II Revealed by Site-Directed Mutagenesis Studies. FRONTIERS IN PLANT SCIENCE 2015; 6:1261. [PMID: 26793230 PMCID: PMC4709441 DOI: 10.3389/fpls.2015.01261] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 12/24/2015] [Indexed: 05/05/2023]
Abstract
Cytochrome b 559 (Cyt b 559) is one of the essential components of the Photosystem II reaction center (PSII). Despite recent accomplishments in understanding the structure and function of PSII, the exact physiological function of Cyt b 559 remains unclear. Cyt b 559 is not involved in the primary electron transfer pathway in PSII but may participate in secondary electron transfer pathways that protect PSII against photoinhibition. Site-directed mutagenesis studies combined with spectroscopic and functional analysis have been used to characterize Cyt b 559 mutant strains and their mutant PSII complex in higher plants, green algae, and cyanobacteria. These integrated studies have provided important in vivo evidence for possible physiological roles of Cyt b 559 in the assembly and stability of PSII, protecting PSII against photoinhibition, and modulating photosynthetic light harvesting. This mini-review presents an overview of recent important progress in site-directed mutagenesis studies of Cyt b 559 and implications for revealing the physiological functions of Cyt b 559 in PSII.
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12
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Sugiura M, Nakamura M, Koyama K, Boussac A. Assembly of oxygen-evolving Photosystem II efficiently occurs with the apo-Cytb559 but the holo-Cytb559 accelerates the recovery of a functional enzyme upon photoinhibition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:276-285. [PMID: 25481108 DOI: 10.1016/j.bbabio.2014.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 11/17/2014] [Accepted: 11/26/2014] [Indexed: 10/24/2022]
Abstract
Cytb559 in Photosystem II is a heterodimeric b-type cytochrome. The subunits, PsbE and PsbF, consist each in a membrane α-helix. Roles for Cytb559 remain elusive. In Thermosynechococcus elongatus, taking advantage of the robustness of the PSII variant with PsbA3 as the D1 subunit (WT*3), 4 mutants were designed hoping to get mutants nevertheless the obligatory phototrophy of this cyanobacterium. In two of them, an axial histidine ligand of the haem-iron was substituted for either a methionine, PsbE/H23M, which could be potentially a ligand or for an alanine, PsbE/H23A, which cannot. In the other mutants, PsbE/Y19F and PsbE/T26P, the environment around PsbE/H23 was expected to be modified. From EPR, MALDI-TOF and O2 evolution activity measurements, the following results were obtained: Whereas the PsbE/H23M and PsbE/H23A mutants assemble only an apo-Cytb559 the steady-state level of active PSII was comparable to that in WT*3. The lack of the haem or, in PsbE/T26P, conversion of the high-potential into a lower potential form, slowed-down the recovery rate of the O2 activity after high-light illumination but did not affect the photoinhibition rate. This resulted in the following order for the steady-state level of active PSII centers under high-light conditions: PsbE/H23M≈PsbE/H23A<< PsbE/Y19F≤PsbE/T26P≤WT*3. These data show i) that the haem has no structural role provided that PsbE and PsbF are present, ii) a lack of correlation between the rate of photoinhibition and the Em of the haem and iii) that the holo-Cytb559 favors the recovery of a functional enzyme upon photoinhibition.
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Affiliation(s)
- Miwa Sugiura
- Proteo-Science Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; Department of Chemistry, Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; PRESTO, Japan Science and Technology Agency (JST), 4-1-8, Honcho, Kawauchi, Saitama 332-0012, Japan.
| | - Makoto Nakamura
- Department of Chemistry, Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Kazumi Koyama
- Proteo-Science Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Alain Boussac
- iBiTec-S, CNRS UMR 8221, CEA Saclay, 91191 Gif-sur-Yvette, France.
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Hamilton ML, Franco E, Deák Z, Schlodder E, Vass I, Nixon PJ. Investigating the photoprotective role of cytochrome b-559 in photosystem II in a mutant with altered ligation of the haem. PLANT & CELL PHYSIOLOGY 2014; 55:1276-85. [PMID: 24850839 DOI: 10.1093/pcp/pcu070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Despite many years of study, the physiological role of cytochrome b-559 (Cyt b-559) within the photosystem II (PSII) complex still remains unclear. Here we describe the analysis of a mutant of the green alga Chlamydomonas reinhardtii in which the His ligand to the haem, provided by the alpha subunit, has been replaced by a Cys residue. The mutant is unable to grow photoautotrophically but can assemble oxygen-evolving PSII supercomplexes to 15-20% of the levels found in the wild-type control. Haem is still detected in the isolated PSII supercomplexes but at sub-stoichiometric levels consistent with weaker binding to the mutated cytochrome. Analysis of PSII activity in cells indicates slowed electron transfer in the mutant between plastoquinones QA and QB. We show that PSII activity in the mutant is more sensitive to chronic photoinhibition than the WT control because of two effects: a faster rate of damage and an impaired PSII repair cycle at the level of synthesis and/or incorporation of D1 into PSII. We also demonstrate that Cyt b-559 plays a role during the critical stage of assembling the Mn4CaO5 cluster. Overall we conclude that Cyt b-559 optimises electron transfer on the acceptor side of PSII and plays physiologically important roles in the assembly, repair and maintenance of the complex.
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Affiliation(s)
- Mary L Hamilton
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington campus, London, SW7 2AZ, UKPresent address: Rothamsted Research, West Common, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Emanuel Franco
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington campus, London, SW7 2AZ, UK
| | - Zsuzsanna Deák
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - Eberhard Schlodder
- Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, D-10623 Berlin, Germany
| | - Imre Vass
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - Peter J Nixon
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington campus, London, SW7 2AZ, UK
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Guerrero F, Zurita JL, Roncel M, Kirilovsky D, Ortega JM. The role of the high potential form of the cytochrome b559: Study of Thermosynechococcus elongatus mutants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:908-19. [PMID: 24613347 DOI: 10.1016/j.bbabio.2014.02.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 02/21/2014] [Accepted: 02/26/2014] [Indexed: 10/25/2022]
Abstract
Cytochrome b559 is an essential component of the photosystem II reaction center in photosynthetic oxygen-evolving organisms, but its function still remains unclear. The use of photosystem II preparations from Thermosynechococcus elongatus of high integrity and activity allowed us to measure for the first time the influence of cytochrome b559 mutations on its midpoint redox potential and on the reduction of the cytochrome b559 by the plastoquinone pool (or QB). In this work, five mutants having a mutation in the α-subunit (I14A, I14S, R18S, I27A and I27T) and one in the β-subunit (F32Y) of cytochrome b559 have been investigated. All the mutations led to a destabilization of the high potential form of the cytochrome b559. The midpoint redox potential of the high potential form was significantly altered in the αR18S and αI27T mutant strains. The αR18S strain also showed a high sensitivity to photoinhibitory illumination and an altered oxidase activity. This was suggested by measurements of light induced oxidation and dark re-reduction of the cytochrome b559 showing that under conditions of a non-functional water oxidation system, once the cytochrome is oxidized by P680(+), the yield of its reduction by QB or the PQ pool was smaller and the kinetic slower in the αR18S mutant than in the wild-type strain. Thus, the extremely positive redox potential of the high potential form of cytochrome b559 could be necessary to ensure efficient oxidation of the PQ pool and to function as an electron reservoir replacing the water oxidation system when it is not operating.
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Affiliation(s)
- Fernando Guerrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Seville, Spain; Laboratoire de Bioénergétique Moléculaire et Photosynthèse, Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA Saclay, 91191 Gif-sur-Yvette cedex, France.
| | - Jorge L Zurita
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Seville, Spain; Laboratoire de Bioénergétique Moléculaire et Photosynthèse, Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA Saclay, 91191 Gif-sur-Yvette cedex, France.
| | - Mercedes Roncel
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Seville, Spain.
| | - Diana Kirilovsky
- Laboratoire de Bioénergétique Moléculaire et Photosynthèse, Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA Saclay, 91191 Gif-sur-Yvette cedex, France.
| | - José M Ortega
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Seville, Spain.
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