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Lv Q, Li S, Du X, Fan Y, Wang M, Song C, Sui F, Liu Y. Transcriptomic response analysis of ultraviolet mutagenesis combined with high carbon acclimation to promote photosynthetic carbon assimilation in Euglena gracilis. Front Microbiol 2024; 15:1444420. [PMID: 39268527 PMCID: PMC11390635 DOI: 10.3389/fmicb.2024.1444420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Accepted: 08/15/2024] [Indexed: 09/15/2024] Open
Abstract
The potential of Euglena gracilis for carbon sequestration offers significant opportunities in the capture and utilization of carbon dioxide (CO2). In this study, a mutant LE-ZW of E. gracilis, capable of efficient growth and carbon sequestration, was obtained through ultraviolet mutagenesis combined with high carbon acclimation. Subsequently, the potential of LE-ZW for carbon assimilation was systematically analyzed. The results demonstrated that the cell density of the LE-ZW was 1.33 times that of the wild type and its carbon sequestration efficiency was 6.67 times that of the wild type when cultured at an optimal CO2 concentration of 5% until day 10. At this time, most key enzyme genes associated with the photosystem membrane protein complex, photosynthetic electron transport chain, antenna protein, and carbon fixation were up-regulated in mutant LE-ZW. Furthermore, after 10 days of culture under 10% CO2, the cell density and carbon sequestration efficiency of LE-ZW reached 1.10 times and 1.54 times of that under 5% CO2, respectively. Transcriptome analysis revealed significant up-regulation of key enzyme genes associated with carbon fixation, central carbon metabolism, and photosynthesis in LE-ZW under a 10% CO2 concentration. Physiological indices such as the amount of oxygen evolution, the values of Fv/Fm, the expression levels of photosynthetic protein genes and the enzyme activity of key enzymes related to photosynthetic carbon assimilation were corroborated by transcriptome data, elucidating that the mutant LE-ZW exhibited augmented photosynthetic carbon sequestration capacity and metabolic activity, thereby demonstrating robust adaptability to a high-carbon environment. This research contributes to a deeper understanding of the carbon assimilation mechanism in photosynthetic protists under elevated CO2 concentrations.
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Affiliation(s)
- Qi Lv
- College of Life Sciences and Technology, Harbin Normal University, Harbin, China
| | - Siping Li
- College of Life Sciences and Technology, Harbin Normal University, Harbin, China
| | - Xinxin Du
- College of Life Sciences and Technology, Harbin Normal University, Harbin, China
| | - Yawen Fan
- College of Life Sciences and Technology, Harbin Normal University, Harbin, China
- Key Laboratory of Biodiversity of Aquatic Organisms, Harbin Normal University, Harbin, China
| | - Mingshuo Wang
- College of Life Sciences and Technology, Harbin Normal University, Harbin, China
| | - Chunhua Song
- College of Life Sciences and Technology, Harbin Normal University, Harbin, China
| | - Fengyang Sui
- College of Life Sciences and Technology, Harbin Normal University, Harbin, China
- Key Laboratory of Biodiversity of Aquatic Organisms, Harbin Normal University, Harbin, China
| | - Yan Liu
- College of Life Sciences and Technology, Harbin Normal University, Harbin, China
- Key Laboratory of Biodiversity of Aquatic Organisms, Harbin Normal University, Harbin, China
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Maekawa S, Ohnishi M, Wada S, Ifuku K, Miyake C. Enhanced Reduction of Ferredoxin in PGR5-Deficient Mutant of Arabidopsis thaliana Stimulated Ferredoxin-Dependent Cyclic Electron Flow around Photosystem I. Int J Mol Sci 2024; 25:2677. [PMID: 38473924 DOI: 10.3390/ijms25052677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 02/12/2024] [Accepted: 02/25/2024] [Indexed: 03/14/2024] Open
Abstract
The molecular entity responsible for catalyzing ferredoxin (Fd)-dependent cyclic electron flow around photosystem I (Fd-CEF) remains unidentified. To reveal the in vivo molecular mechanism of Fd-CEF, evaluating ferredoxin reduction-oxidation kinetics proves to be a reliable indicator of Fd-CEF activity. Recent research has demonstrated that the expression of Fd-CEF activity is contingent upon the oxidation of plastoquinone. Moreover, chloroplast NAD(P)H dehydrogenase does not catalyze Fd-CEF in Arabidopsis thaliana. In this study, we analyzed the impact of reduced Fd on Fd-CEF activity by comparing wild-type and pgr5-deficient mutants (pgr5hope1). PGR5 has been proposed as the mediator of Fd-CEF, and pgr5hope1 exhibited a comparable CO2 assimilation rate and the same reduction-oxidation level of PQ as the wild type. However, P700 oxidation was suppressed with highly reduced Fd in pgr5hope1, unlike in the wild type. As anticipated, the Fd-CEF activity was enhanced in pgr5hope1 compared to the wild type, and its activity further increased with the oxidation of PQ due to the elevated CO2 assimilation rate. This in vivo research clearly demonstrates that the expression of Fd-CEF activity requires not only reduced Fd but also oxidized PQ. Importantly, PGR5 was found to not catalyze Fd-CEF, challenging previous assumptions about its role in this process.
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Affiliation(s)
- Shu Maekawa
- Graduate School for Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-Ku, Kobe 657-8501, Japan
| | - Miho Ohnishi
- Graduate School for Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-Ku, Kobe 657-8501, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Gobancho, Kyoto 606-8502, Japan
| | - Shinya Wada
- Graduate School for Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-Ku, Kobe 657-8501, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Gobancho, Kyoto 606-8502, Japan
| | - Kentaro Ifuku
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Gobancho, Kyoto 606-8502, Japan
- Graduate School for Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Chikahiro Miyake
- Graduate School for Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-Ku, Kobe 657-8501, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Gobancho, Kyoto 606-8502, Japan
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Melicher P, Dvořák P, Řehák J, Šamajová O, Pechan T, Šamaj J, Takáč T. Methyl viologen-induced changes in the Arabidopsis proteome implicate PATELLIN 4 in oxidative stress responses. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:405-421. [PMID: 37728561 PMCID: PMC10735431 DOI: 10.1093/jxb/erad363] [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: 06/21/2023] [Accepted: 09/12/2023] [Indexed: 09/21/2023]
Abstract
The photosynthesis-induced accumulation of reactive oxygen species in chloroplasts can lead to oxidative stress, triggering changes in protein synthesis, degradation, and the assembly/disassembly of protein complexes. Using shot-gun proteomics, we identified methyl viologen-induced changes in protein abundance in wild-type Arabidopsis and oxidative stress-hypersensitive fsd1-1 and fsd1-2 knockout mutants, which are deficient in IRON SUPEROXIDE DISMUTASE 1 (FSD1). The levels of proteins that are localized in chloroplasts and the cytoplasm were modified in all lines treated with methyl viologen. Compared with the wild-type, fsd1 mutants showed significant changes in metabolic protein and chloroplast chaperone levels, together with increased ratio of cytoplasmic, peroxisomal, and mitochondrial proteins. Different responses in proteins involved in the disassembly of photosystem II-light harvesting chlorophyll a/b binding proteins were observed. Moreover, the abundance of PATELLIN 4, a phospholipid-binding protein enriched in stomatal lineage, was decreased in response to methyl viologen. Reverse genetic studies using patl4 knockout mutants and a PATELLIN 4 complemented line indicate that PATELLIN 4 affects plant responses to oxidative stress by effects on stomatal closure.
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Affiliation(s)
- Pavol Melicher
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Petr Dvořák
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Jan Řehák
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Olga Šamajová
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Tibor Pechan
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi Agricultural and Forestry Experiment Station, Mississippi State University, Starkville, MS, USA
| | - Jozef Šamaj
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Tomáš Takáč
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
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Szwalec M, Bujnowicz Ł, Sarewicz M, Osyczka A. Unexpected Heme Redox Potential Values Implicate an Uphill Step in Cytochrome b6f. J Phys Chem B 2022; 126:9771-9780. [PMID: 36399615 PMCID: PMC9720722 DOI: 10.1021/acs.jpcb.2c05729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cytochromes bc, key enzymes of respiration and photosynthesis, contain a highly conserved two-heme motif supporting cross-membrane electron transport (ET) that connects the two catalytic quinone-binding sites (Qn and Qp). Typically, this ET occurs from the low- to high-potential heme b, but in photosynthetic cytochrome b6f, the redox midpoint potentials (Ems) of these hemes remain uncertain. Our systematic redox titration analysis based on three independent and comprehensive low-temperature spectroscopies (continuous wave and pulse electron paramagnetic resonance (EPR) and optical spectroscopies) allowed for unambiguous assignment of spectral components of hemes in cytochrome b6f and revealed that Em of heme bn is unexpectedly low. Consequently, the cross-membrane ET occurs from the high- to low-potential heme introducing an uphill step in the energy landscape for the catalytic reaction. This slows down the ET through a low-potential chain, which can influence the mechanisms of reactions taking place at both Qp and Qn sites and modulate the efficiency of cyclic and linear ET in photosynthesis.
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Hussain S, Ulhassan Z, Brestic M, Zivcak M, Allakhverdiev SI, Yang X, Safdar ME, Yang W, Liu W. Photosynthesis research under climate change. PHOTOSYNTHESIS RESEARCH 2021; 150:5-19. [PMID: 34235625 DOI: 10.1007/s11120-021-00861-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/28/2021] [Indexed: 05/13/2023]
Abstract
Increasing global population and climate change uncertainties have compelled increased photosynthetic efficiency and yields to ensure food security over the coming decades. Potentially, genetic manipulation and minimization of carbon or energy losses can be ideal to boost photosynthetic efficiency or crop productivity. Despite significant efforts, limited success has been achieved. There is a need for thorough improvement in key photosynthetic limiting factors, such as stomatal conductance, mesophyll conductance, biochemical capacity combined with Rubisco, the Calvin-Benson cycle, thylakoid membrane electron transport, nonphotochemical quenching, and carbon metabolism or fixation pathways. In addition, the mechanistic basis for the enhancement in photosynthetic adaptation to environmental variables such as light intensity, temperature and elevated CO2 requires further investigation. This review sheds light on strategies to improve plant photosynthesis by targeting these intrinsic photosynthetic limitations and external environmental factors.
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Affiliation(s)
- Sajad Hussain
- College of Agronomy, Sichuan Agricultural University, 211-Huimin Road, Wenjiang District, Chengdu, 611130, People's Republic of China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China (Ministry of Agriculture), Sichuan Engineering Research Center for Crop Strip Intercropping System, Sichuan Agricultural University, Chengdu, People's Republic of China
| | - Zaid Ulhassan
- Institute of Crop Science, Ministry of Agriculture and Rural Affairs Laboratory of Spectroscopy Sensing, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Marian Brestic
- Department of Plant Physiology, Slovak University of Agriculture, 94976, Nitra, Slovakia
| | - Marek Zivcak
- Department of Plant Physiology, Slovak University of Agriculture, 94976, Nitra, Slovakia
| | - Suleyman I Allakhverdiev
- К.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St. 35, Moscow, Russia, 127276
| | - Xinghong Yang
- Department of Plant Physiology, College of Life Sciences, Shandong Agricultural University, Daizong Road No. 61, 271018, Taian, People's Republic of China
| | | | - Wenyu Yang
- College of Agronomy, Sichuan Agricultural University, 211-Huimin Road, Wenjiang District, Chengdu, 611130, People's Republic of China.
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China (Ministry of Agriculture), Sichuan Engineering Research Center for Crop Strip Intercropping System, Sichuan Agricultural University, Chengdu, People's Republic of China.
| | - Weiguo Liu
- College of Agronomy, Sichuan Agricultural University, 211-Huimin Road, Wenjiang District, Chengdu, 611130, People's Republic of China.
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China (Ministry of Agriculture), Sichuan Engineering Research Center for Crop Strip Intercropping System, Sichuan Agricultural University, Chengdu, People's Republic of China.
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Balaji S. The transferred translocases: An old wine in a new bottle. Biotechnol Appl Biochem 2021; 69:1587-1610. [PMID: 34324237 DOI: 10.1002/bab.2230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/23/2021] [Indexed: 11/12/2022]
Abstract
The role of translocases was underappreciated and was not included as a separate class in the enzyme commission until August 2018. The recent research interests in proteomics of orphan enzymes, ionomics, and metallomics along with high-throughput sequencing technologies generated overwhelming data and revamped this enzyme into a separate class. This offers a great opportunity to understand the role of new or orphan enzymes in general and specifically translocases. The enzymes belonging to translocases regulate/permeate the transfer of ions or molecules across the membranes. These enzyme entries were previously associated with other enzyme classes, which are now transferred to a new enzyme class 7 (EC 7). The entries that are reclassified are important to extend the enzyme list, and it is the need of the hour. Accordingly, there is an upgradation of entries of this class of enzymes in several databases. This review is a concise compilation of translocases with reference to the number of entries currently available in the databases. This review also focuses on function as well as dysfunction of translocases during normal and disordered states, respectively.
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Affiliation(s)
- S Balaji
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, 576 104, India
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Vermot A, Petit-Härtlein I, Smith SME, Fieschi F. NADPH Oxidases (NOX): An Overview from Discovery, Molecular Mechanisms to Physiology and Pathology. Antioxidants (Basel) 2021; 10:890. [PMID: 34205998 PMCID: PMC8228183 DOI: 10.3390/antiox10060890] [Citation(s) in RCA: 260] [Impact Index Per Article: 86.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/21/2021] [Accepted: 05/26/2021] [Indexed: 01/17/2023] Open
Abstract
The reactive oxygen species (ROS)-producing enzyme NADPH oxidase (NOX) was first identified in the membrane of phagocytic cells. For many years, its only known role was in immune defense, where its ROS production leads to the destruction of pathogens by the immune cells. NOX from phagocytes catalyzes, via one-electron trans-membrane transfer to molecular oxygen, the production of the superoxide anion. Over the years, six human homologs of the catalytic subunit of the phagocyte NADPH oxidase were found: NOX1, NOX3, NOX4, NOX5, DUOX1, and DUOX2. Together with the NOX2/gp91phox component present in the phagocyte NADPH oxidase assembly itself, the homologs are now referred to as the NOX family of NADPH oxidases. NOX are complex multidomain proteins with varying requirements for assembly with combinations of other proteins for activity. The recent structural insights acquired on both prokaryotic and eukaryotic NOX open new perspectives for the understanding of the molecular mechanisms inherent to NOX regulation and ROS production (superoxide or hydrogen peroxide). This new structural information will certainly inform new investigations of human disease. As specialized ROS producers, NOX enzymes participate in numerous crucial physiological processes, including host defense, the post-translational processing of proteins, cellular signaling, regulation of gene expression, and cell differentiation. These diversities of physiological context will be discussed in this review. We also discuss NOX misregulation, which can contribute to a wide range of severe pathologies, such as atherosclerosis, hypertension, diabetic nephropathy, lung fibrosis, cancer, or neurodegenerative diseases, giving this family of membrane proteins a strong therapeutic interest.
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Affiliation(s)
- Annelise Vermot
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 38000 Grenoble, France; (A.V.); (I.P.-H.)
| | - Isabelle Petit-Härtlein
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 38000 Grenoble, France; (A.V.); (I.P.-H.)
| | - Susan M. E. Smith
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144, USA;
| | - Franck Fieschi
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 38000 Grenoble, France; (A.V.); (I.P.-H.)
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Zhang C, Wang H, Xu Y, Zhang S, Wang J, Hu B, Hou X, Li Y, Liu T. Enhanced Relative Electron Transport Rate Contributes to Increased Photosynthetic Capacity in Autotetraploid Pak Choi. PLANT & CELL PHYSIOLOGY 2020; 61:761-774. [PMID: 31904850 DOI: 10.1093/pcp/pcz238] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/26/2019] [Indexed: 06/10/2023]
Abstract
Autopolyploids often show growth advantages over their diploid progenitors because of their increased photosynthetic activity; however, the underlying molecular basis of such mechanism remains elusive. In this study, we aimed to characterize autotetraploid pak choi (Brassica rapa ssp. chinensis) at the physiological, cellular and molecular levels. Autotetraploid pak choi has thicker leaves than its diploid counterparts, with relatively larger intercellular spaces and cell size and greater grana thylakoid height. Photosynthetic data showed that the relative electron transport rate (rETR) was markedly higher in autotetraploid than in diploid pak choi. Transcriptomic data revealed that the expressions of genes involved in 'photosynthesis' biological process and 'thylakoids' cellular component were mainly regulated in autotetraploids. Overall, our findings suggested that the increased rETR in the thylakoids contributed to the increased photosynthetic capacity of autotetraploid leaves. Furthermore, we found that the enhanced rETR is associated with increased BrPetC expression, which is likely altered by histone modification. The ectopic expression of BrPetC in Arabidopsis thaliana led to increased rETR and biomass, which were decreased in BrPetC-silenced pak choi. Autotetraploid pak choi also shows altered hormone levels, which was likely responsible for the increased drought resistance and the impaired powdery mildew resistance of this lineage. Our findings further our understanding on how autotetraploidy provides growth advantages to plants.
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Affiliation(s)
- Changwei Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture, Department of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Huiyu Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture, Department of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuanyuan Xu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture, Department of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Shuning Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture, Department of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Jianjun Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture, Department of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Bing Hu
- Department of Life Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Xilin Hou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture, Department of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Ying Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture, Department of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Tongkun Liu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture, Department of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
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Singer SD, Soolanayakanahally RY, Foroud NA, Kroebel R. Biotechnological strategies for improved photosynthesis in a future of elevated atmospheric CO 2. PLANTA 2019; 251:24. [PMID: 31784816 DOI: 10.1007/s00425-019-03301-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
The improvement of photosynthesis using biotechnological approaches has been the focus of much research. It is now vital that these strategies be assessed under future atmospheric conditions. The demand for crop products is expanding at an alarming rate due to population growth, enhanced affluence, increased per capita calorie consumption, and an escalating need for plant-based bioproducts. While solving this issue will undoubtedly involve a multifaceted approach, improving crop productivity will almost certainly provide one piece of the puzzle. The improvement of photosynthetic efficiency has been a long-standing goal of plant biotechnologists as possibly one of the last remaining means of achieving higher yielding crops. However, the vast majority of these studies have not taken into consideration possible outcomes when these plants are grown long-term under the elevated CO2 concentrations (e[CO2]) that will be evident in the not too distant future. Due to the considerable effect that CO2 levels have on the photosynthetic process, these assessments should become commonplace as a means of ensuring that research in this field focuses on the most effective approaches for our future climate scenarios. In this review, we discuss the main biotechnological research strategies that are currently underway with the aim of improving photosynthetic efficiency and biomass production/yields in the context of a future of e[CO2], as well as alternative approaches that may provide further photosynthetic benefits under these conditions.
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Affiliation(s)
- Stacy D Singer
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada.
| | - Raju Y Soolanayakanahally
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, SK, S7N 0X2, Canada
| | - Nora A Foroud
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada
| | - Roland Kroebel
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada
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Tacchino F, Succurro A, Ebenhöh O, Gerace D. Optimal efficiency of the Q-cycle mechanism around physiological temperatures from an open quantum systems approach. Sci Rep 2019; 9:16657. [PMID: 31723177 PMCID: PMC6853958 DOI: 10.1038/s41598-019-52842-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 10/14/2019] [Indexed: 01/17/2023] Open
Abstract
The Q-cycle mechanism entering the electron and proton transport chain in oxygenic photosynthesis is an example of how biological processes can be efficiently investigated with elementary microscopic models. Here we address the problem of energy transport across the cellular membrane from an open quantum system theoretical perspective. We model the cytochrome \documentclass[12pt]{minimal}
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\begin{document}$${b}_{6}\,f$$\end{document}b6f protein complex under cyclic electron flow conditions starting from a simplified kinetic model, which is hereby revisited in terms of a Markovian quantum master equation formulation and spin-boson Hamiltonian treatment. We apply this model to theoretically demonstrate an optimal thermodynamic efficiency of the Q-cycle around ambient and physiologically relevant temperature conditions. Furthermore, we determine the quantum yield of this complex biochemical process after setting the electrochemical potentials to values well established in the literature. The present work suggests that the theory of quantum open systems can successfully push forward our theoretical understanding of complex biological systems working close to the quantum/classical boundary.
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Affiliation(s)
| | - Antonella Succurro
- Institute of Quantitative and Theoretical Biology, Heinrich Heine University, 40225, Düsseldorf, Germany.,Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, 40225, Düsseldorf, Germany.,Life and Medical Sciences (LIMES) Institute and West German Genome Center, University of Bonn, Bonn, Germany
| | - Oliver Ebenhöh
- Institute of Quantitative and Theoretical Biology, Heinrich Heine University, 40225, Düsseldorf, Germany.,Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Dario Gerace
- Department of Physics, University of Pavia, I-27100, Pavia, Italy.
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Binding of ferredoxin NADP + oxidoreductase (FNR) to plant photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:689-698. [PMID: 31336103 DOI: 10.1016/j.bbabio.2019.07.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/11/2019] [Accepted: 07/18/2019] [Indexed: 12/17/2022]
Abstract
The binding of FNR to PSI has been postulated long ago, however, a clear evidence is still missing. In this work, using isothermal titration calorimetry (ITC), we found that FNR binds to photosystem I with its light harvesting complex I (PSI-LHCI) from C. reinhardtii with a 1:1 stoichiometry, a Kd of ~0.8 μM and ∆H of -20.7 kcal/mol. Titrations at different temperatures were used to determine the heat capacity change, ∆CP, of the binding, through which the size of the interface area between the proteins was assessed as ~3000 Å2. In a different set of ITC experiments, introduction of various sucrose concentrations was used to estimate that ~95 water molecules are released to the solvent. These observations support the notion of a binding site shared by few of the photosystem I - light harvesting complex I (PSI-LHCI) subunits in addition to PsaE. Based on these results, a hypothetical model was built for the binding site of FNR at PSI, using known crystallographic structures of: cyanobacterial PSI in complex with ferredoxin (Fd), plant PSI-LHCI and Fd:FNR complex from cyanobacteria. FNR binding site location is proposed to be at the foot of the stromal ridge and above the inner LHCI belt. It is expected to form contacts with PsaE, PsaB, PsaF and at least one of the LHCI. In addition, a ~4.5-fold increased affinity between FNR and PSI-LHCI under crowded 1 M sucrose environment led us to conclude that in C. reinhardtii FNR also functions as a subunit of PSI-LHCI.
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Simkin AJ, López-Calcagno PE, Raines CA. Feeding the world: improving photosynthetic efficiency for sustainable crop production. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:1119-1140. [PMID: 30772919 PMCID: PMC6395887 DOI: 10.1093/jxb/ery445] [Citation(s) in RCA: 224] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/27/2018] [Indexed: 05/18/2023]
Abstract
A number of recent studies have provided strong support demonstrating that improving the photosynthetic processes through genetic engineering can provide an avenue to improve yield potential. The major focus of this review is on improvement of the Calvin-Benson cycle and electron transport. Consideration is also given to how altering regulatory process may provide an additional route to increase photosynthetic efficiency. Here we summarize some of the recent successes that have been observed through genetic manipulation of photosynthesis, showing that, in both the glasshouse and the field, yield can be increased by >40%. These results provide a clear demonstration of the potential for increasing yield through improvements in photosynthesis. In the final section, we consider the need to stack improvement in photosynthetic traits with traits that target the yield gap in order to provide robust germplasm for different crops across the globe.
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Affiliation(s)
- Andrew J Simkin
- NIAB EMR, New Road, East Malling, Kent, UK
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester, UK
| | | | - Christine A Raines
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester, UK
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Tortosa M, Cartea ME, Rodríguez VM, Velasco P. Unraveling the metabolic response of Brassica oleracea exposed to Xanthomonas campestris pv. campestris. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2018; 98:3675-3683. [PMID: 29315593 DOI: 10.1002/jsfa.8876] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/29/2017] [Accepted: 01/02/2018] [Indexed: 06/07/2023]
Abstract
BACKGROUND Brassica crops together with cereals represent the basis of world supplies. Due to their importance, the production losses caused by Xanthomonas campestris pv. campestris (Xcc) infection represent a high economic impact. Understanding molecular and biochemical mechanisms of plants is essential to develop resistant crops with durable protection against diseases. In this regard, metabolomics has emerged as a valuable technology to provide an overview of the biological status of a plant exposed to a disease. This study investigated the dynamic changes in the metabolic profile of Brassica oleracea plants during an Xcc infection from leaves collected at five different days post infection using a mass spectrometry approach. RESULTS Results showed that Xcc infection causes dynamic changes in the metabolome of B. oleracea. Moreover, induction/repression pattern of the metabolites implicated in the response follows a complex dynamics during infection progression, indicating a complex temporal response. Specific metabolic pathways such as alkaloids, coumarins or sphingolipids are postulated as promising key role candidates in the infection response. CONCLUSION This work tries to decipher the changes produced on Brassica crops metabolome under Xcc infection and represents a step forward in the understanding of B. oleracea-Xcc interaction. © 2018 Society of Chemical Industry.
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Affiliation(s)
- María Tortosa
- Group of Genetics, Breeding and Biochemistry of Brassicas, Misión Biológica de Galicia (CSIC), Pontevedra, Spain
| | - María E Cartea
- Group of Genetics, Breeding and Biochemistry of Brassicas, Misión Biológica de Galicia (CSIC), Pontevedra, Spain
| | - Víctor M Rodríguez
- Group of Genetics, Breeding and Biochemistry of Brassicas, Misión Biológica de Galicia (CSIC), Pontevedra, Spain
| | - Pablo Velasco
- Group of Genetics, Breeding and Biochemistry of Brassicas, Misión Biológica de Galicia (CSIC), Pontevedra, Spain
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Li L, Aro EM, Millar AH. Mechanisms of Photodamage and Protein Turnover in Photoinhibition. TRENDS IN PLANT SCIENCE 2018; 23:667-676. [PMID: 29887276 DOI: 10.1016/j.tplants.2018.05.004] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/05/2018] [Accepted: 05/08/2018] [Indexed: 05/05/2023]
Abstract
Rapid protein degradation and replacement is an important response to photodamage and a means of photoprotection by recovering proteostasis. Protein turnover and translation efficiency studies have discovered fast turnover subunits in cytochrome b6f and the NAD(P)H dehydrogenase (NDH) complex, in addition to PSII subunit D1. Mutations of these complexes have been linked to enhanced photodamage at least partially via cyclic electron flow. Photodamage and photoprotection involving cytochrome b6f, NDH complex, cyclic electron flow, PSI, and nonphotochemical quenching proteins have been reported. Here, we propose that the rapid turnover of specific proteins in cytochrome b6f and the NDH complex need to be characterised and compared with the inhibition of PSII by excess excitation energy and PSI by excess electron flux to expand our understanding of photoinhibition mechanisms.
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Affiliation(s)
- Lei Li
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, 35 Stirling Hwy, 6009, Perth, WA, Australia
| | - Eva-Mari Aro
- Finnish Centre of Excellence in Molecular Biology of Primary Producers, Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - A Harvey Millar
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, 35 Stirling Hwy, 6009, Perth, WA, Australia.
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15
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Putative model based on iTRAQ proteomics for Spirulina morphogenesis mechanisms. J Proteomics 2018; 171:73-80. [DOI: 10.1016/j.jprot.2017.03.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/13/2017] [Accepted: 03/19/2017] [Indexed: 11/21/2022]
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16
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Simkin AJ, McAusland L, Lawson T, Raines CA. Overexpression of the RieskeFeS Protein Increases Electron Transport Rates and Biomass Yield. PLANT PHYSIOLOGY 2017; 175:134-145. [PMID: 28754840 DOI: 10.1101/133702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/27/2017] [Indexed: 05/22/2023]
Abstract
In this study, we generated transgenic Arabidopsis (Arabidopsis thaliana) plants overexpressing the Rieske FeS protein (PetC), a component of the cytochrome b6f (cyt b6f) complex. Increasing the levels of this protein resulted in concomitant increases in the levels of cyt f (PetA) and cyt b6 (PetB), core proteins of the cyt b6f complex. Interestingly, an increase in the levels of proteins in both the photosystem I (PSI) and PSII complexes also was seen in the Rieske FeS overexpression plants. Although the mechanisms leading to these changes remain to be identified, the transgenic plants presented here provide novel tools to explore this. Importantly, overexpression of the Rieske FeS protein resulted in substantial and significant impacts on the quantum efficiency of PSI and PSII, electron transport, biomass, and seed yield in Arabidopsis plants. These results demonstrate the potential for manipulating electron transport processes to increase crop productivity.
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Affiliation(s)
- Andrew J Simkin
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Lorna McAusland
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Tracy Lawson
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Christine A Raines
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
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The competition between chemistry and biology in assembling iron–sulfur derivatives. Molecular structures and electrochemistry. Part III. {[Fe2S2](Cys)3(X)} (X=Asp, Arg, His) and {[Fe2S2](Cys)2(His)2} proteins. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2015.07.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Heme c i or c n of the Cytochrome b 6 f Complex, A Short Retrospective. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2016. [DOI: 10.1007/978-94-017-7481-9_15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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Schöttler MA, Tóth SZ, Boulouis A, Kahlau S. Photosynthetic complex stoichiometry dynamics in higher plants: biogenesis, function, and turnover of ATP synthase and the cytochrome b6f complex. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2373-400. [PMID: 25540437 DOI: 10.1093/jxb/eru495] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
During plant development and in response to fluctuating environmental conditions, large changes in leaf assimilation capacity and in the metabolic consumption of ATP and NADPH produced by the photosynthetic apparatus can occur. To minimize cytotoxic side reactions, such as the production of reactive oxygen species, photosynthetic electron transport needs to be adjusted to the metabolic demand. The cytochrome b6f complex and chloroplast ATP synthase form the predominant sites of photosynthetic flux control. Accordingly, both respond strongly to changing environmental conditions and metabolic states. Usually, their contents are strictly co-regulated. Thereby, the capacity for proton influx into the lumen, which is controlled by electron flux through the cytochrome b6f complex, is balanced with proton efflux through ATP synthase, which drives ATP synthesis. We discuss the environmental, systemic, and metabolic signals triggering the stoichiometry adjustments of ATP synthase and the cytochrome b6f complex. The contribution of transcriptional and post-transcriptional regulation of subunit synthesis, and the importance of auxiliary proteins required for complex assembly in achieving the stoichiometry adjustments is described. Finally, current knowledge on the stability and turnover of both complexes is summarized.
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Affiliation(s)
- Mark Aurel Schöttler
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Szilvia Z Tóth
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Alix Boulouis
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Sabine Kahlau
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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Fristedt R, Martins NF, Strenkert D, Clarke CA, Suchoszek M, Thiele W, Schöttler MA, Merchant SS. The thylakoid membrane protein CGL160 supports CF1CF0 ATP synthase accumulation in Arabidopsis thaliana. PLoS One 2015; 10:e0121658. [PMID: 25835989 PMCID: PMC4383579 DOI: 10.1371/journal.pone.0121658] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/11/2015] [Indexed: 11/18/2022] Open
Abstract
The biogenesis of the major thylakoid protein complexes of the photosynthetic apparatus requires auxiliary proteins supporting individual assembly steps. Here, we identify a plant lineage specific gene, CGL160, whose homolog, atp1, co-occurs with ATP synthase subunits in an operon-like arrangement in many cyanobacteria. Arabidopsis thaliana T-DNA insertion mutants, which no longer accumulate the nucleus-encoded CGL160 protein, accumulate less than 25% of wild-type levels of the chloroplast ATP synthase. Severe cosmetic or growth phenotypes result under either short day or fluctuating light growth conditions, respectively, but this is ameliorated under long day constant light growth conditions where the growth, ATP synthase activity and photosynthetic electron transport of the mutants are less affected. Accumulation of other photosynthetic complexes is largely unaffected in cgl160 mutants, suggesting that CGL160 is a specific assembly or stability factor for the CF1CF0 complex. CGL160 is not found in the mature assembled complex but it does interact specifically with subunits of ATP synthase, predominantly those in the extrinsic CF1 sub-complex. We suggest therefore that it may facilitate the assembly of CF1 into the holocomplex.
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Affiliation(s)
- Rikard Fristedt
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California, United States of America
- Institute for Genomics and Proteomics UCLA, Los Angeles, California, United States of America
| | | | - Daniela Strenkert
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California, United States of America
| | - Cornelia A. Clarke
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California, United States of America
| | - Monika Suchoszek
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Wolfram Thiele
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | | | - Sabeeha S. Merchant
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California, United States of America
- Institute for Genomics and Proteomics UCLA, Los Angeles, California, United States of America
- * E-mail:
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Transmembrane signaling and assembly of the cytochrome b6f-lipidic charge transfer complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:1295-308. [PMID: 23507619 DOI: 10.1016/j.bbabio.2013.03.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/27/2013] [Accepted: 03/06/2013] [Indexed: 12/30/2022]
Abstract
Structure-function properties of the cytochrome b6f complex are sufficiently unique compared to those of the cytochrome bc1 complex that b6f should not be considered a trivially modified bc1 complex. A unique property of the dimeric b6f complex is its involvement in transmembrane signaling associated with the p-side oxidation of plastoquinol. Structure analysis of lipid binding sites in the cyanobacterial b6f complex prepared by hydrophobic chromatography shows that the space occupied by the H transmembrane helix in the cytochrome b subunit of the bc1 complex is mostly filled by a lipid in the b6f crystal structure. It is suggested that this space can be filled by the domain of a transmembrane signaling protein. The identification of lipid sites and likely function defines the intra-membrane conserved central core of the b6f complex, consisting of the seven trans-membrane helices of the cytochrome b and subunit IV polypeptides. The other six TM helices, contributed by cytochrome f, the iron-sulfur protein, and the four peripheral single span subunits, define a peripheral less conserved domain of the complex. The distribution of conserved and non-conserved domains of each monomer of the complex, and the position and inferred function of a number of the lipids, suggests a model for the sequential assembly in the membrane of the eight subunits of the b6f complex, in which the assembly is initiated by formation of the cytochrome b6-subunit IV core sub-complex in a monomer unit. Two conformations of the unique lipidic chlorophyll a, defined in crystal structures, are described, and functions of the outlying β-carotene, a possible 'latch' in supercomplex formation, are discussed. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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22
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Stirbet A. Chlorophyll a fluorescence induction: a personal perspective of the thermal phase, the J-I-P rise. PHOTOSYNTHESIS RESEARCH 2012; 113:15-61. [PMID: 22810945 DOI: 10.1007/s11120-012-9754-5] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 05/29/2012] [Indexed: 05/03/2023]
Abstract
The fast (up to 1 s) chlorophyll (Chl) a fluorescence induction (FI) curve, measured under saturating continuous light, has a photochemical phase, the O-J rise, related mainly to the reduction of Q(A), the primary electron acceptor plastoquinone of Photosystem II (PSII); here, the fluorescence rise depends strongly on the number of photons absorbed. This is followed by a thermal phase, the J-I-P rise, which disappears at subfreezing temperatures. According to the mainstream interpretation of the fast FI, the variable fluorescence originates from PSII antenna, and the oxidized Q(A) is the most important quencher influencing the O-J-I-P curve. As the reaction centers of PSII are gradually closed by the photochemical reduction of Q(A), Chl fluorescence, F, rises from the O level (the minimal level) to the P level (the peak); yet, the relationship between F and [Q(A) (-)] is not linear, due to the presence of other quenchers and modifiers. Several alternative theories have been proposed, which give different interpretations of the O-J-I-P transient. The main idea in these alternative theories is that in saturating light, Q(A) is almost completely reduced already at the end of the photochemical phase O-J, but the fluorescence yield is lower than its maximum value due to the presence of either a second quencher besides Q(A), or there is an another process quenching the fluorescence; in the second quencher hypothesis, this quencher is consumed (or the process of quenching the fluorescence is reversed) during the thermal phase J-I-P. In this review, we discuss these theories. Based on our critical examination, that includes pros and cons of each theory, as well mathematical modeling, we conclude that the mainstream interpretation of the O-J-I-P transient is the most credible one, as none of the alternative ideas provide adequate explanation or experimental proof for the almost complete reduction of Q(A) at the end of the O-J phase, and for the origin of the fluorescence rise during the thermal phase. However, we suggest that some of the factors influencing the fluorescence yield that have been proposed in these newer theories, as e.g., the membrane potential ΔΨ, as suggested by Vredenberg and his associates, can potentially contribute to modulate the O-J-I-P transient in parallel with the reduction of Q(A), through changes at the PSII antenna and/or at the reaction center, or, possibly, through the control of the oxidation-reduction of the PQ-pool, including proton transfer into the lumen, as suggested by Rubin and his associates. We present in this review our personal perspective mainly on our understanding of the thermal phase, the J-I-P rise during Chl a FI in plants and algae.
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23
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Wang QJ, Singh A, Li H, Nedbal L, Sherman LA, Govindjee, Whitmarsh J. Net light-induced oxygen evolution in photosystem I deletion mutants of the cyanobacterium Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:792-801. [DOI: 10.1016/j.bbabio.2012.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 12/29/2011] [Accepted: 01/03/2012] [Indexed: 10/14/2022]
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Kallas T. Cytochrome b 6 f Complex at the Heart of Energy Transduction and Redox Signaling. PHOTOSYNTHESIS 2012. [DOI: 10.1007/978-94-007-1579-0_21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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25
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Garcia Costas AM, Liu Z, Tomsho LP, Schuster SC, Ward DM, Bryant DA. Complete genome of Candidatus Chloracidobacterium thermophilum, a chlorophyll-based photoheterotroph belonging to the phylum Acidobacteria. Environ Microbiol 2011; 14:177-90. [DOI: 10.1111/j.1462-2920.2011.02592.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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26
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Cramer WA, Hasan SS, Yamashita E. The Q cycle of cytochrome bc complexes: a structure perspective. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:788-802. [PMID: 21352799 DOI: 10.1016/j.bbabio.2011.02.006] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 02/08/2011] [Accepted: 02/13/2011] [Indexed: 12/01/2022]
Abstract
Aspects of the crystal structures of the hetero-oligomeric cytochrome bc(1) and b(6)f ("bc") complexes relevant to their electron/proton transfer function and the associated redox reactions of the lipophilic quinones are discussed. Differences between the b(6)f and bc(1) complexes are emphasized. The cytochrome bc(1) and b(6)f dimeric complexes diverge in structure from a core of subunits that coordinate redox groups consisting of two bis-histidine coordinated hemes, a heme b(n) and b(p) on the electrochemically negative (n) and positive (p) sides of the complex, the high potential [2Fe-2S] cluster and c-type heme at the p-side aqueous interface and aqueous phase, respectively, and quinone/quinol binding sites on the n- and p-sides of the complex. The bc(1) and b(6)f complexes diverge in subunit composition and structure away from this core. b(6)f Also contains additional prosthetic groups including a c-type heme c(n) on the n-side, and a chlorophyll a and β-carotene. Common structure aspects; functions of the symmetric dimer. (I) Quinone exchange with the bilayer. An inter-monomer protein-free cavity of approximately 30Å along the membrane normal×25Å (central inter-monomer distance)×15Å (depth in the center), is common to both bc(1) and b(6)f complexes, providing a niche in which the lipophilic quinone/quinol (Q/QH(2)) can be exchanged with the membrane bilayer. (II) Electron transfer. The dimeric structure and the proximity of the two hemes b(p) on the electrochemically positive side of the complex in the two monomer units allow the possibility of two alternate routes of electron transfer across the complex from heme b(p) to b(n): intra-monomer and inter-monomer involving electron cross-over between the two hemes b(p). A structure-based summary of inter-heme distances in seven bc complexes, representing mitochondrial, chromatophore, cyanobacterial, and algal sources, indicates that, based on the distance parameter, the intra-monomer pathway would be favored kinetically. (III) Separation of quinone binding sites. A consequence of the dimer structure and the position of the Q/QH(2) binding sites is that the p-side QH(2) oxidation and n-side Q reduction sites are each well separated. Therefore, in the event of an overlap in residence time by QH(2) or Q molecules at the two oxidation or reduction sites, their spatial separation would result in minimal steric interference between extended Q or QH(2) isoprenoid chains. (IV) Trans-membrane QH(2)/Q transfer. (i) n/p-side QH(2)/Q transfer may be hindered by lipid acyl chains; (ii) the shorter less hindered inter-monomer pathway across the complex would not pass through the center of the cavity, as inferred from the n-side antimycin site on one monomer and the p-side stigmatellin site on the other residing on the same surface of the complex. (V) Narrow p-side portal for QH(2)/Q passage. The [2Fe-2S] cluster that serves as oxidant, and whose histidine ligand serves as a H(+) acceptor in the oxidation of QH(2), is connected to the inter-monomer cavity by a narrow extended portal, which is also occupied in the b(6)f complex by the 20 carbon phytyl chain of the bound chlorophyll.
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Affiliation(s)
- William A Cramer
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.
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On the relation between the Kautsky effect (chlorophyll a fluorescence induction) and Photosystem II: basics and applications of the OJIP fluorescence transient. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:236-57. [PMID: 21295993 DOI: 10.1016/j.jphotobiol.2010.12.010] [Citation(s) in RCA: 485] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 12/20/2010] [Accepted: 12/22/2010] [Indexed: 11/23/2022]
Abstract
Chlorophyll a fluorescence is a highly sensitive, non-destructive, and reliable tool for measuring, rather quickly, photosynthetic efficiency, particularly of Photosystem II (PSII), the water-plastoquinone oxidoreductase. We briefly review here the connection between the fast (up to 2 s) chlorophyll fluorescence rise and PSII, as well as the empirical use of the fluorescence rise kinetics in understanding photosynthetic reactions, particularly of PSII. When dark-adapted photosynthetic samples are exposed to light, a fluorescence induction is observed, known as the Kautsky effect, after Hans Kautsky, the discoverer of the phenomenon showing the existence of variable fluorescence. The chlorophyll fluorescence intensity rises from a minimum level (the O level), in less than 1 s, to a maximum level (the P-level) via two intermediate steps labeled J and I. This is followed by a decline to a lower semi-steady state level, the S level, which is reached in about one minute. We provide here an educational review on how this phenomenon has been exploited through analysis of the fast OJIP fluorescence transient, by discussing basic assumptions, derivation of equations, as well as application to PSII-related questions.
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28
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Li Y, Wang Z, Xu T, Tu W, Liu C, Zhang Y, Yang C. Reorganization of photosystem II is involved in the rapid photosynthetic recovery of desert moss Syntrichia caninervis upon rehydration. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:1390-7. [PMID: 20719403 DOI: 10.1016/j.jplph.2010.05.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 05/07/2010] [Accepted: 05/17/2010] [Indexed: 05/12/2023]
Abstract
The moss Syntrichia caninervis (S. caninervis) is one of the dominant species in biological soil crusts of deserts. It has long been the focus of scientific research because of its ecological value. Moreover, S. caninervis has a special significance in biogenesis research because it is characterized by its fast restoration of photosynthesis upon onset of rehydration of the desiccated organism. In order to study the mechanisms of rapid photosynthetic recovery in mosses upon rewatering, we investigated the kinetics of the recovery process of photosynthetic activity in photosystem (PS) II, with an indirect assessment of the photochemical processes based on chlorophyll (Chl) fluorescence measurements. Our results showed that recovery can be divided into two phases. The fast initial phase, completed within 3 min, was characterized by a quick increase in maximal quantum efficiency of PSII (F(v)/F(m)). Over 50% of the PSII activities, including excitation energy transfer, oxygen evolution, charge separation, and electron transport, recovered within 0.5 min after rehydration. The second, slow phase was dominated by the increase of plastoquinone (PQ) reduction and the equilibrium of the energy transport from the inner antenna to the reaction center (RC) of PSII. Analysis of the recovery process in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU) revealed that blocking the electron transport from Q(A) to Q(B) did not hamper Chl synthesis or Chl organization in thylakoid membranes under light conditions. A de novo chloroplast protein synthesis was not necessary for the initial recovery of photochemical activity in PSII. In conclusion, the moss's ability for rapid recovery upon rehydration is related to Chl synthesis, quick structural reorganization of PSII, and fast restoration of PSII activity without de novo chloroplast protein synthesis.
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Affiliation(s)
- Yang Li
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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Baymann F, Nitschke W. Heliobacterial Rieske/cytb complex. PHOTOSYNTHESIS RESEARCH 2010; 104:177-187. [PMID: 20091229 DOI: 10.1007/s11120-009-9524-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 12/21/2009] [Indexed: 05/28/2023]
Abstract
Data on structure and function of the Rieske/cytb complex from Heliobacteria are scarce. They indicate that the complex is related to the b (6) f complex in agreement with the phylogenetic position of the organism. It is composed of a diheme cytochrome c, and a Rieske iron-sulfur protein, together with transmembrane cytochrome b (6) and subunit IV. Additional small subunits may be part of the complex. The cofactor content comprises heme c (i), first discovered in the Q(i) binding pocket of b (6) f complexes. The redox midpoint potentials are more negative than in b (6) f complex in agreement with the lower redox midpoint potentials (by about 150 mV) of its reaction partners, menaquinone, and cytochrome c (553). The enzyme is implicated in cyclic electron transfer around the RCI. Functional studies are favored by the absence of antennae and the simple photosynthetic reaction chain but are hampered by the high oxygen sensitivity of the organism, its chlorophyll, and lipids.
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Affiliation(s)
- F Baymann
- BIP, Centre National de la Recherche Scientifique, UPR9036, IFR88, 31 Chemin Joseph Aiguier, Marseille, France.
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30
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Characterization of two cytochrome b 6 proteins from the cyanobacterium Gloeobacter violaceus PCC 7421. J Bioenerg Biomembr 2010; 42:517-26. [DOI: 10.1007/s10863-010-9279-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 01/22/2010] [Indexed: 11/29/2022]
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31
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Twigg AI, Baniulis D, Cramer WA, Hendrich MP. EPR detection of an O(2) surrogate bound to heme c(n) of the cytochrome b(6)f complex. J Am Chem Soc 2009; 131:12536-7. [PMID: 19689132 DOI: 10.1021/ja905171c] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ligand-binding properties of the unique heme c(n) of the cyt b(6)f complex, which is bridged to the heme b(n), are studied with EPR spectroscopy. Despite an open coordination site, high-spin heme c(n) in the oxidized state does not bind typical heme ligands such as cyanide, indicating their inaccessibility to the heme. In the reduced state, heme c(n) binds the O(2) surrogate NO to give a five-coordinate S = (1)/(2) [FeNO](7) complex, indicating that the site is accessible in the reduced state of the protein. The binding of NO implies that the heme c(n) can also bind O(2). Given the significant number of experimentally documented pathways for which a plastoquinol oxidase has been proposed, but the actual oxidase not identified, it is proposed that one of the functions of heme c(n), the only prosthetic group in the electron transport chain with oxidase-like properties, is the putative oxidase.
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Affiliation(s)
- Anna I Twigg
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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Tsunoyama Y, Bernát G, Dyczmons NG, Schneider D, Rögner M. Multiple Rieske proteins enable short- and long-term light adaptation of Synechocystis sp. PCC 6803. J Biol Chem 2009; 284:27875-27883. [PMID: 19674969 PMCID: PMC2788838 DOI: 10.1074/jbc.m109.011189] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 08/12/2009] [Indexed: 11/06/2022] Open
Abstract
In contrast to eukaryotes, most cyanobacteria contain several isoforms of the Rieske iron-sulfur protein, PetC, resulting in heterogeneity in the composition of the cytochrome b(6)f complexes. Of three isoforms in the mesophilic cyanobacterium Synechocystis PCC 6803, PetC1 is the major Rieske protein in the cytochrome b(6)f complex, whereas the physiological function of PetC2 and PetC3 is still uncertain. Comparison of wild type and various petC-deficient strains under selected light conditions revealed distinct functional differences: high-light exposure of wild type cells resulted in a significantly enhanced petC2 transcript level, whereas a Delta petC1 mutant showed a low cytochrome b(6)f content, low electron flux, and a considerably increased accumulation of cytochrome-bd oxidase. In contrast to wild type and Delta petC1, Delta petC2 and Delta petC3 strains still grew fast under high-light conditions although all three Rieske proteins are required for maximal electron transport rates. Although the presence of PetC3 appears to be required for activation of the cyclic electron transport, state transitions were more effective in the absence of PetC2 and/or PetC3. In summary, our data suggest defined roles of the various PetC proteins in short- and long-term light adaptation.
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Affiliation(s)
- Yuichi Tsunoyama
- Department of Plant Biochemistry, Ruhr-University Bochum, 44780 Bochum, Germany; Division of Biology, Radioisotope Research Center, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Gábor Bernát
- Department of Plant Biochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Nina G Dyczmons
- Department of Plant Biochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Dirk Schneider
- Department of Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Matthias Rögner
- Department of Plant Biochemistry, Ruhr-University Bochum, 44780 Bochum, Germany.
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33
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Sang M, Ma F, Xie J, Chen XB, Wang KB, Qin XC, Wang WD, Zhao JQ, Li LB, Zhang JP, Kuang TY. High-light induced singlet oxygen formation in cytochrome b(6)f complex from Bryopsis corticulans as detected by EPR spectroscopy. Biophys Chem 2009; 146:7-12. [PMID: 19861232 DOI: 10.1016/j.bpc.2009.09.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 09/24/2009] [Accepted: 09/26/2009] [Indexed: 11/16/2022]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy was used to detect the light-induced formation of singlet oxygen ((1)O(2)*) in the intact and the Rieske-depleted cytochrome b(6)f complexes (Cyt b(6)f) from Bryopsis corticulans, as well as in the isolated Rieske Fe-S protein. It is shown that, under white-light illumination and aerobic conditions, chlorophyll a (Chl a) bound in the intact Cyt b(6)f can be bleached by light-induced (1)O(2)*, and that the (1)O(2)* production can be promoted by D(2)O or scavenged by extraneous antioxidants such as l-histidine, ascorbate, beta-carotene and glutathione. Under similar experimental conditions, (1)O(2)* was also detected in the Rieske-depleted Cyt b(6)f complex, but not in the isolated Rieske Fe-S protein. The results prove that Chl a cofactor, rather than Rieske Fe-S protein, is the specific site of (1)O(2)* formation, a conclusion which draws further support from the generation of (1)O(2)* with selective excitation of Chl a using monocolor red light.
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Affiliation(s)
- Min Sang
- Institute of Botany, Chinese Academy of Sciences, Beijing, PR China
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34
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Laganowsky A, Gómez SM, Whitelegge JP, Nishio JN. Hydroponics on a chip: Analysis of the Fe deficient Arabidopsis thylakoid membrane proteome. J Proteomics 2009; 72:397-415. [DOI: 10.1016/j.jprot.2009.01.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Abstract
Despite recent elucidation of the three-dimensional structure of major photosynthetic complexes, our understanding of light energy conversion in plant chloroplasts and microalgae under physiological conditions requires exploring the dynamics of photosynthesis. The photosynthetic apparatus is a flexible molecular machine that can acclimate to metabolic and light fluctuations in a matter of seconds and minutes. On a longer time scale, changes in environmental cues trigger acclimation responses that elicit intracellular signaling between the nucleo-cytosol and chloroplast resulting in modification of the biogenesis of the photosynthetic machinery. Here we attempt to integrate well-established knowledge on the functional flexibility of light-harvesting and electron transfer processes, which has greatly benefited from genetic approaches, with data derived from the wealth of recent transcriptomic and proteomic studies of acclimation responses in photosynthetic eukaroytes.
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Affiliation(s)
- Stephan Eberhard
- Université Pierre et Marie Curie, Institut de Biologie Physico-Chimique, F-75005 Paris, France
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36
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Baniulis D, Yamashita E, Zhang H, Hasan SS, Cramer WA. Structure-function of the cytochrome b6f complex. Photochem Photobiol 2009; 84:1349-58. [PMID: 19067956 DOI: 10.1111/j.1751-1097.2008.00444.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The structure and function of the cytochrome b6f complex is considered in the context of recent crystal structures of the complex as an eight subunit, 220 kDa symmetric dimeric complex obtained from the thermophilic cyanobacterium, Mastigocladus laminosus, and the green alga, Chlamydomonas reinhardtii. A major problem confronted in crystallization of the cyanobacterial complex, proteolysis of three of the subunits, is discussed along with initial efforts to identify the protease. The evolution of these cytochrome complexes is illustrated by conservation of the hydrophobic heme-binding transmembrane domain of the cyt b polypeptide between b6f and bc1 complexes, and the rubredoxin-like membrane proximal domain of the Rieske [2Fe-2S] protein. Pathways of coupled electron and proton transfer are discussed in the framework of a modified Q cycle, in which the heme c(n), not found in the bc1 complex, but electronically tightly coupled to the heme b(n) of the b6f complex, is included. Crystal structures of the cyanobacterial complex with the quinone analogue inhibitors, NQNO or tridecyl-stigmatellin, show the latter to be ligands of heme c(n), implicating heme c(n) as an n-side plastoquinone reductase. Existing questions include (a) the details of the shuttle of: (i) the [2Fe-2S] protein between the membrane-bound PQH2 electron/H+ donor and the cytochrome f acceptor to complete the p-side electron transfer circuit; (ii) PQ/PQH2 between n- and p-sides of the complex across the intermonomer quinone exchange cavity, through the narrow portal connecting the cavity with the p-side [2Fe-2S] niche; (b) the role of the n-side of the b6f complex and heme c(n) in regulation of the relative rates of noncyclic and cyclic electron transfer. The likely presence of cyclic electron transport in the b6f complex, and of heme c(n) in the firmicute bc complex suggests the concept that hemes b(n)-c(n) define a branch point in bc complexes that can support electron transport pathways that differ in detail from the Q cycle supported by the bc1 complex.
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Affiliation(s)
- D Baniulis
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
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The Cytochrome bc 1 and Related bc Complexes: The Rieske/Cytochrome b Complex as the Functional Core of a Central Electron/Proton Transfer Complex. THE PURPLE PHOTOTROPHIC BACTERIA 2009. [DOI: 10.1007/978-1-4020-8815-5_23] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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38
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Sumimoto H. Structure, regulation and evolution of Nox-family NADPH oxidases that produce reactive oxygen species. FEBS J 2008; 275:3249-77. [PMID: 18513324 DOI: 10.1111/j.1742-4658.2008.06488.x] [Citation(s) in RCA: 516] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
NADPH oxidases of the Nox family exist in various supergroups of eukaryotes but not in prokaryotes, and play crucial roles in a variety of biological processes, such as host defense, signal transduction, and hormone synthesis. In conjunction with NADPH oxidation, Nox enzymes reduce molecular oxygen to superoxide as a primary product, and this is further converted to various reactive oxygen species. The electron-transferring system in Nox is composed of the C-terminal cytoplasmic region homologous to the prokaryotic (and organelle) enzyme ferredoxin reductase and the N-terminal six transmembrane segments containing two hemes, a structure similar to that of cytochrome b of the mitochondrial bc(1) complex. During the course of eukaryote evolution, Nox enzymes have developed regulatory mechanisms, depending on their functions, by inserting a regulatory domain (or motif) into their own sequences or by obtaining a tightly associated protein as a regulatory subunit. For example, one to four Ca(2+)-binding EF-hand motifs are present at the N-termini in several subfamilies, such as the respiratory burst oxidase homolog (Rboh) subfamily in land plants (the supergroup Plantae), the NoxC subfamily in social amoebae (the Amoebozoa), and the Nox5 and dual oxidase (Duox) subfamilies in animals (the Opisthokonta), whereas an SH3 domain is inserted into the ferredoxin-NADP(+) reductase region of two Nox enzymes in Naegleria gruberi, a unicellular organism that belongs to the supergroup Excavata. Members of the Nox1-4 subfamily in animals form a stable heterodimer with the membrane protein p22(phox), which functions as a docking site for the SH3 domain-containing regulatory proteins p47(phox), p67(phox), and p40(phox); the small GTPase Rac binds to p67(phox) (or its homologous protein), which serves as a switch for Nox activation. Similarly, Rac activates the fungal NoxA via binding to the p67(phox)-like protein Nox regulator (NoxR). In plants, on the other hand, this GTPase directly interacts with the N-terminus of Rboh, leading to superoxide production. Here I describe the regulation of Nox-family oxidases on the basis of three-dimensional structures and evolutionary conservation.
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Affiliation(s)
- Hideki Sumimoto
- Medical Institute of Bioregulation, Kyushu University, Fukuoka CREST, Japan Science and Technology Agency, Tokyo, Japan.
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Kanervo E, Singh M, Suorsa M, Paakkarinen V, Aro E, Battchikova N, Aro EM. Expression of protein complexes and individual proteins upon transition of etioplasts to chloroplasts in pea (Pisum sativum). PLANT & CELL PHYSIOLOGY 2008; 49:396-410. [PMID: 18263621 DOI: 10.1093/pcp/pcn016] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The protein complexes of pea (Pisum sativum L.) etioplasts, etio-chloroplasts and chloroplasts were examined using 2D Blue Native/SDS-PAGE. The most prominent protein complexes in etioplasts were the ATPase and the Clp and FtsH protease complexes which probably have a crucial role in the biogenesis of etioplasts and chloroplasts. Also the cytochrome b(6)f (Cyt b(6)f) complex was assembled in the etioplast membrane, as well as Rubisco, at least partially, in the stroma. These complexes are composed of proteins encoded by both the plastid and nuclear genomes, indicating that a functional cross-talk exists between pea etioplasts and the nucleus. In contrast, the proteins and protein complexes that bind chlorophyll, with the PetD subunit and the entire Cyt b(6)f complex as an exception, did not accumulate in etioplasts. Nevertheless, some PSII core components such as PsbE and the luminal oxygen-evolvong complex (OEC) proteins PsbO and PsbP accumulated efficiently in etioplasts. After 6 h de-etiolation, a complete PSII core complex appeared with 40% of the maximal photochemical efficiency, but a fully functional PSII was recorded only after 24 h illumination. Similarly, the core complex of PSI was assembled after 6 h illumination, whereas the PSI-light-harvesting complex I was stably assembled only in chloroplasts illuminated for 24 h. Moreover, a battery of proteins responsible for defense against oxidative stress accumulated particularly in etioplasts, including the stromal and thylakoidal forms of ascorbate peroxidase, glutathione reductase and PsbS.
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Affiliation(s)
- Eira Kanervo
- Department of Biology, University of Turku, FIN-20014 Turku, Finland
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Lyska D, Paradies S, Meierhoff K, Westhoff P. HCF208, a Homolog of Chlamydomonas CCB2, is Required for Accumulation of Native Cytochrome b6 in Arabidopsis thaliana. ACTA ACUST UNITED AC 2007; 48:1737-46. [DOI: 10.1093/pcp/pcm146] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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41
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Lenaz G, Fato R, Formiggini G, Genova ML. The role of Coenzyme Q in mitochondrial electron transport. Mitochondrion 2007; 7 Suppl:S8-33. [PMID: 17485246 DOI: 10.1016/j.mito.2007.03.009] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Revised: 03/20/2007] [Accepted: 03/22/2007] [Indexed: 12/21/2022]
Abstract
In mitochondria, most Coenzyme Q is free in the lipid bilayer; the question as to whether tightly bound, non-exchangeable Coenzyme Q molecules exist in mitochondrial complexes is still an open question. We review the mechanism of inter-complex electron transfer mediated by ubiquinone and discuss the kinetic consequences of the supramolecular organization of the respiratory complexes (randomly dispersed vs. super-complexes) in terms of Coenzyme Q pool behavior vs. metabolic channeling, respectively, both in physiological and in some pathological conditions. As an example of intra-complex electron transfer, we discuss in particular Complex I, a topic that is still under active investigation.
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Affiliation(s)
- Giorgio Lenaz
- Dipartimento di Biochimica, Università di Bologna, Via Irnerio 48, 40126 Bologna, Italy.
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