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Subramanyam R, Tomo T, Eaton-Rye JJ, Yilmaz G, Allakhverdiev SI. International conference on "Photosynthesis and Hydrogen Energy Research for Sustainability-2023": in honor of Robert Blankenship, Győző Garab, Michael Grätzel, Norman Hüner and Gunnar Öquist. PHOTOSYNTHESIS RESEARCH 2024; 161:141-150. [PMID: 38502256 DOI: 10.1007/s11120-024-01087-5] [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: 11/29/2023] [Accepted: 02/06/2024] [Indexed: 03/21/2024]
Abstract
The 11th International Photosynthesis Conference on Hydrogen Energy Research and Sustainability 2023 was organized in honor of Robert Blankenship, Győző Garab, Michael Grätzel, Norman Hüner, and Gunnar Öquist, in Istanbul, Türkiye at Bahçeşehir University Future Campus from 03 to 09 July 2023. It was jointly supported by the International Society of Photosynthesis Research (ISPR) and the International Association for Hydrogen Energy (IAHE). In this article we provide brief details of the conference, its events, keynote speakers, and the scientific contribution of scientists honored at this conference. Further, we also describe the participation of young researchers, their talks, and their awards.
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Affiliation(s)
- Rajagopal Subramanyam
- Department of Plant Science, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, 500046, India
| | - Tatsuya Tomo
- Department of Physics, Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Julian J Eaton-Rye
- Department of Biochemistry, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand
| | - Girayhan Yilmaz
- Faculty of Engineering and Natural Sciences, Bahcesehir University, Istanbul, Turkey
| | - Suleyman I Allakhverdiev
- Faculty of Engineering and Natural Sciences, Bahcesehir University, Istanbul, Turkey.
- К.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St. 35, Moscow, Russia, 127276.
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Krynická V, Komenda J. The Role of FtsH Complexes in the Response to Abiotic Stress in Cyanobacteria. PLANT & CELL PHYSIOLOGY 2024; 65:1103-1114. [PMID: 38619128 PMCID: PMC11287208 DOI: 10.1093/pcp/pcae042] [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: 12/28/2023] [Revised: 03/24/2024] [Accepted: 04/12/2024] [Indexed: 04/16/2024]
Abstract
FtsH proteases (FtsHs) belong to intramembrane ATP-dependent metalloproteases which are widely distributed in eubacteria, mitochondria and chloroplasts. The best-studied roles of FtsH in Escherichia coli include quality control of membrane proteins, regulation of response to heat shock, superoxide stress and viral infection, and control of lipopolysaccharide biosynthesis. While heterotrophic bacteria mostly contain a single indispensable FtsH complex, photosynthetic cyanobacteria usually contain three FtsH complexes: two heterocomplexes and one homocomplex. The essential cytoplasmic FtsH1/3 most probably fulfills a role similar to other bacterial FtsHs, whereas the thylakoid FtsH2/3 heterocomplex and FtsH4 homocomplex appear to maintain the photosynthetic apparatus of cyanobacteria and optimize its functionality. Moreover, recent studies suggest the involvement of all FtsH proteases in a complex response to nutrient stresses. In this review, we aim to comprehensively evaluate the functions of the cyanobacterial FtsHs specifically under stress conditions with emphasis on nutrient deficiency and high irradiance. We also point to various unresolved issues concerning FtsH functions, which deserve further attention.
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Affiliation(s)
- Vendula Krynická
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Opatovický Mlýn, Novohradská 237, Třeboň 37901, The Czech Republic
| | - Josef Komenda
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Opatovický Mlýn, Novohradská 237, Třeboň 37901, The Czech Republic
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Li L, Liu Q, Li B, Zhao Y. The Effecting Mechanisms of 100 nm Sized Polystyrene Nanoplastics on the Typical Coastal Alexandrium tamarense. Int J Mol Sci 2024; 25:7297. [PMID: 39000403 PMCID: PMC11242399 DOI: 10.3390/ijms25137297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Revised: 06/14/2024] [Accepted: 06/30/2024] [Indexed: 07/16/2024] Open
Abstract
Due to the increase in nanoplastics (NPs) abundance in aquatic environments, their effects on phytoplankton have aroused large research attention. In this study, 100 nm sized polystyrene NPs were chosen to investigate their effecting performance and mechanisms on a typical dinoflagellates Alexandrium tamarense. The results indicated the population growth and photosynthetic efficiencies of A. tamarense were significantly inhibited by NPs exposure, as well as the increase in cellular total carotenoids and paralytic shellfish toxins (PSTs). Meanwhile, the cellar ROS levels increased, corresponding to the increased activities or contents of multiple antioxidant components, including SOD, CAT, GPX, GR, GSH and GSSG. The transcriptional results support the physiological-biochemical results and further revealed the down-regulation of genes encoding the light reaction centers (PSI and PSII) and up-regulation of genes encoding the antioxidant components. Up-regulation of genes encoding key enzymes of the Calvin cycle and glycolytic pathway together with the TCA cycle could accelerate organic carbon and ATP production for A. tamarense cells resistant to NPs stress. Finally, more Glu and acetyl-CoA produced by the enhanced GSH cycle and the glycolytic pathway, respectively, accompanied by the up-regulation of Glu and Arg biosynthesis genes supported the increase in the PST contents under NPs exposure. This study established a data set involving physiological-biochemical changes and gene information about marine dinoflagellates responding to NPs, providing a data basis for further evaluating the ecological risk of NPs in marine environments.
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Affiliation(s)
- Luying Li
- Marine Science and Technology College, Zhejiang Ocean University, Zhoushan 316022, China;
- Department of Marine Ecology, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China;
| | - Qian Liu
- Marine Science Research Institute of Shandong Province, Qingdao 266104, China;
- Qingdao Key Laboratory of Coastal Ecological Restoration and Security, Qingdao 266104, China
| | - Bo Li
- Marine Science and Technology College, Zhejiang Ocean University, Zhoushan 316022, China;
| | - Yan Zhao
- Department of Marine Ecology, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China;
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Penzler JF, Naranjo B, Walz S, Marino G, Kleine T, Leister D. A pgr5 suppressor screen uncovers two distinct suppression mechanisms and links cytochrome b6f complex stability to PGR5. THE PLANT CELL 2024:koae098. [PMID: 38781425 DOI: 10.1093/plcell/koae098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 03/13/2024] [Indexed: 05/25/2024]
Abstract
PROTON GRADIENT REGULATION5 (PGR5) is thought to promote cyclic electron flow, and its deficiency impairs photosynthetic control and increases photosensitivity of photosystem (PS) I, leading to seedling lethality under fluctuating light (FL). By screening for Arabidopsis (Arabidopsis thaliana) suppressor mutations that rescue the seedling lethality of pgr5 plants under FL, we identified a portfolio of mutations in 12 different genes. These mutations affect either PSII function, cytochrome b6f (cyt b6f) assembly, plastocyanin (PC) accumulation, the CHLOROPLAST FRUCTOSE-1,6-BISPHOSPHATASE1 (cFBP1), or its negative regulator ATYPICAL CYS HIS-RICH THIOREDOXIN2 (ACHT2). The characterization of the mutants indicates that the recovery of viability can in most cases be explained by the restoration of PSI donor side limitation, which is caused by reduced electron flow to PSI due to defects in PSII, cyt b6f, or PC. Inactivation of cFBP1 or its negative regulator ACHT2 results in increased levels of the NADH dehydrogenase-like complex. This increased activity may be responsible for suppressing the pgr5 phenotype under FL conditions. Plants that lack both PGR5 and DE-ETIOLATION-INDUCED PROTEIN1 (DEIP1)/NEW TINY ALBINO1 (NTA1), previously thought to be essential for cyt b6f assembly, are viable and accumulate cyt b6f. We suggest that PGR5 can have a negative effect on the cyt b6f complex and that DEIP1/NTA1 can ameliorate this negative effect.
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Affiliation(s)
- Jan-Ferdinand Penzler
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Belén Naranjo
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Sabrina Walz
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Giada Marino
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Tatjana Kleine
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
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Rasul F, You D, Jiang Y, Liu X, Daroch M. Thermophilic cyanobacteria-exciting, yet challenging biotechnological chassis. Appl Microbiol Biotechnol 2024; 108:270. [PMID: 38512481 PMCID: PMC10957709 DOI: 10.1007/s00253-024-13082-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/23/2024]
Abstract
Thermophilic cyanobacteria are prokaryotic photoautotrophic microorganisms capable of growth between 45 and 73 °C. They are typically found in hot springs where they serve as essential primary producers. Several key features make these robust photosynthetic microbes biotechnologically relevant. These are highly stable proteins and their complexes, the ability to actively transport and concentrate inorganic carbon and other nutrients, to serve as gene donors, microbial cell factories, and sources of bioactive metabolites. A thorough investigation of the recent progress in thermophilic cyanobacteria reveals a significant increase in the number of newly isolated and delineated organisms and wide application of thermophilic light-harvesting components in biohybrid devices. Yet despite these achievements, there are still deficiencies at the high-end of the biotechnological learning curve, notably in genetic engineering and gene editing. Thermostable proteins could be more widely employed, and an extensive pool of newly available genetic data could be better utilised. In this manuscript, we attempt to showcase the most important recent advances in thermophilic cyanobacterial biotechnology and provide an overview of the future direction of the field and challenges that need to be overcome before thermophilic cyanobacterial biotechnology can bridge the gap with highly advanced biotechnology of their mesophilic counterparts. KEY POINTS: • Increased interest in all aspects of thermophilic cyanobacteria in recent years • Light harvesting components remain the most biotechnologically relevant • Lack of reliable molecular biology tools hinders further development of the chassis.
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Affiliation(s)
- Faiz Rasul
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Dawei You
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Ying Jiang
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Xiangjian Liu
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Maurycy Daroch
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
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Tikhonov AN. The cytochrome b 6f complex: plastoquinol oxidation and regulation of electron transport in chloroplasts. PHOTOSYNTHESIS RESEARCH 2024; 159:203-227. [PMID: 37369875 DOI: 10.1007/s11120-023-01034-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
In oxygenic photosynthetic systems, the cytochrome b6f (Cytb6f) complex (plastoquinol:plastocyanin oxidoreductase) is a heart of the hub that provides connectivity between photosystems (PS) II and I. In this review, the structure and function of the Cytb6f complex are briefly outlined, being focused on the mechanisms of a bifurcated (two-electron) oxidation of plastoquinol (PQH2). In plant chloroplasts, under a wide range of experimental conditions (pH and temperature), a diffusion of PQH2 from PSII to the Cytb6f does not limit the intersystem electron transport. The overall rate of PQH2 turnover is determined mainly by the first step of the bifurcated oxidation of PQH2 at the catalytic site Qo, i.e., the reaction of electron transfer from PQH2 to the Fe2S2 cluster of the high-potential Rieske iron-sulfur protein (ISP). This point has been supported by the quantum chemical analysis of PQH2 oxidation within the framework of a model system including the Fe2S2 cluster of the ISP and surrounding amino acids, the low-potential heme b6L, Glu78 and 2,3,5-trimethylbenzoquinol (the tail-less analog of PQH2). Other structure-function relationships and mechanisms of electron transport regulation of oxygenic photosynthesis associated with the Cytb6f complex are briefly outlined: pH-dependent control of the intersystem electron transport and the regulatory balance between the operation of linear and cyclic electron transfer chains.
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Affiliation(s)
- Alexander N Tikhonov
- Department of Biophysics, Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russian Federation, 119991.
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Dai W, Wang X, Zhuang M, Sun J, Shen Y, Xia Z, Wu T, Jiang R, Li A, Bi F, Zhang J, He P. Responses of photosynthesis-related genes in Sargassum horneri to high temperature stress. MARINE POLLUTION BULLETIN 2024; 199:115944. [PMID: 38142666 DOI: 10.1016/j.marpolbul.2023.115944] [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: 07/28/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 12/26/2023]
Abstract
Golden tide outbreak threatened the marine ecological environment. Sargassum horneri is a single dominant species of the Yellow Sea golden tide, which growth and development are affected by changes in sea water temperature. This study investigated the photosynthetic physiology of copper algae and found that the growth rate, chlorophyll a content, carotenoid content, Fv/Fm, and maximum electron transfer efficiency were significantly reduced, indicating that Sargassum horneri was under stress under high temperature. In this study, high-throughput sequencing was used to analyze the response mechanisms of photosynthesis-related genes in S. horneri under high temperature stress. The results showed that most of the photosynthesis-related genes in S. horneri were downregulated and photosynthesis was inhibited under high temperature stress. However, the expression levels of ferredoxin, ferredoxin-NADP reductase, light-harvesting protein complexes, and oxygen-evolving complex genes were significantly upregulated (P ≤ 0.05) after five days of high temperature treatment. This study found that photosynthesis related genes play a crucial role in regulating the photosynthetic response of S. horneri to high temperature stress.
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Affiliation(s)
- Wei Dai
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Xiaoran Wang
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Minmin Zhuang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Jingyi Sun
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Yifei Shen
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Zhangyi Xia
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Tingjian Wu
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Ruitong Jiang
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Aiqin Li
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Fangling Bi
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Jianheng Zhang
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China.
| | - Peimin He
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China.
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Lan Y, Chen Q, Mi H. NdhS interacts with cytochrome b 6 f to form a complex in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:706-716. [PMID: 37493543 DOI: 10.1111/tpj.16398] [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: 02/14/2023] [Revised: 06/27/2023] [Accepted: 07/05/2023] [Indexed: 07/27/2023]
Abstract
Cyclic electron transport (CET) around photosystem I (PSI) is crucial for photosynthesis to perform photoprotection and sustain the balance of ATP and NADPH. However, the critical component of CET, cyt b6 f complex (cyt b6 f), functions in CET has yet to be understood entirely. In this study, we found that NdhS, a subunit of NADPH dehydrogenase-like (NDH) complex, interacted with cyt b6 f to form a complex in Arabidopsis. This interaction depended on the N-terminal extension of NdhS, which was conserved in eukaryotic plants but defective in prokaryotic algae. The migration of NdhS was much more in cyt b6 f than in PSI-NDH super-complex. Based on these results, we suggested that NdhS and NADP+ oxidoreductase provide a docking domain for the mobile electron carrier ferredoxin to transfer electrons to the plastoquinone pool via cyt b6 f in eukaryotic photosynthesis.
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Affiliation(s)
- Yixin Lan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences / Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai, 200032, P.R. China
| | - Qi Chen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences / Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai, 200032, P.R. China
| | - Hualing Mi
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences / Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai, 200032, P.R. China
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Telegina TA, Vechtomova YL, Aybush AV, Buglak AA, Kritsky MS. Isomerization of carotenoids in photosynthesis and metabolic adaptation. Biophys Rev 2023; 15:887-906. [PMID: 37974987 PMCID: PMC10643480 DOI: 10.1007/s12551-023-01156-4] [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: 07/01/2023] [Accepted: 09/22/2023] [Indexed: 11/19/2023] Open
Abstract
In nature, carotenoids are present as trans- and cis-isomers. Various physical and chemical factors like light, heat, acids, catalytic agents, and photosensitizers can contribute to the isomerization of carotenoids. Living organisms in the process of evolution have developed different mechanisms of adaptation to light stress, which can also involve isomeric forms of carotenoids. Particularly, light stress conditions can enhance isomerization processes. The purpose of this work is to review the recent studies on cis/trans isomerization of carotenoids as well as the role of carotenoid isomers for the light capture, energy transfer, photoprotection in light-harvesting complexes, and reaction centers of the photosynthetic apparatus of plants and other photosynthetic organisms. The review also presents recent studies of carotenoid isomers for the biomedical aspects, showing cis- and trans-isomers differ in bioavailability, antioxidant activity and biological activity, which can be used for therapeutic and prophylactic purposes.
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Affiliation(s)
- T. A. Telegina
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 2, 119071 Moscow, Russia
| | - Yuliya L. Vechtomova
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 2, 119071 Moscow, Russia
| | - A. V. Aybush
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 4 Kosygina Street, Building 1, 119991 Moscow, Russia
| | - A. A. Buglak
- Saint Petersburg State University, 7-9 Universitetskaya Emb., 199034 Saint Petersburg, Russia
| | - M. S. Kritsky
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 2, 119071 Moscow, Russia
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Ariga K. Liquid-Liquid Interfacial Nanoarchitectonics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2305636. [PMID: 37641176 DOI: 10.1002/smll.202305636] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/28/2023] [Indexed: 08/31/2023]
Abstract
Science in the small world has become a crucial key that has the potential to revolutionize materials technology. This trend is embodied in the postnanotechnology concept of nanoarchitectonics. The goal of nanoarchitectonics is to create bio-like functional structures, in which self-organized and hierarchical structures are working efficiently. Liquid-liquid interface like environments such as cell membrane surface are indispensable for the expression of biological functions through the accumulation and organization of functional materials. From this viewpoint, it is necessary to reconsider the liquid-liquid interface as a medium where nanoarchitectonics can play an active role. In this review, liquid-liquid interfacial nanoarchitectonics is classified by component materials such as organic, inorganic, carbon, and bio, and recent research examples are discussed. Examples discussed in this paper include molecular aggregates, supramolecular polymers, conductive polymers film, crystal-like capsules, block copolymer assemblies, covalent organic framework (COF) films, complex crystals, inorganic nanosheets, colloidosomes, fullerene assemblies, all-carbon π-conjugated graphite nanosheets, carbon nanoskins and fullerphene thin films at liquid-liquid interfaces. Furthermore, at the liquid-liquid interface using perfluorocarbons and aqueous phases, cell differentiation controls are discussed with the self-assembled structure of biomaterials. The significance of liquid-liquid interfacial nanoarchitectonics in the future development of materials will then be discussed.
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Affiliation(s)
- Katsuhiko Ariga
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, 305-0044, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwa-no-ha Kashiwa, Tokyo, 277-8561, Japan
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Luo W, Luo YW. Diurnally dynamic iron allocation promotes N 2 fixation in marine dominant diazotroph Trichodesmium. Comput Struct Biotechnol J 2023; 21:3503-3512. [PMID: 37484493 PMCID: PMC10362294 DOI: 10.1016/j.csbj.2023.07.006] [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: 02/14/2023] [Revised: 06/15/2023] [Accepted: 07/04/2023] [Indexed: 07/25/2023] Open
Abstract
Trichodesmium is the dominant photoautotrophic dinitrogen (N2) fixer (diazotroph) in the ocean. Iron is an important factor limiting growth of marine diazotrophs including Trichodesmium mainly because of high iron content of its N2-fixing enzyme, nitrogenase. However, it still lacks a quantitative understanding of how dynamic iron allocation among physiological processes acts to regulate growth and N2 fixation in Trichodesmium. Here, we constructed a model of Trichodesmium trichome in which intracellular iron could be dynamically re-allocated in photosystems and nitrogenase during the daytime. The results demonstrate that the dynamic iron allocation enhances modeled N2 fixation and growth rates of Trichodesmium, especially in iron-limited conditions, albeit having a marginal impact under high iron concentrations. Although the reuse of iron during a day is an apparent cause that dynamic iron allocation can benefit Trichodesmium under iron limitation, our model reveals two important mechanisms. First, the release of iron from photosystems downregulates the intracellular oxygen (O2) production and reduces the demand of respiratory protection, a process that Trichodesmium wastefully respires carbohydrates to create a lower O2 window for N2 fixation. Hence, more carbohydrates can be used in growth. Second, lower allocation of iron to nitrogenase during early daytime, a period when photosynthesis is active and intracellular O2 is high, reduces the amount of iron that is trapped in the inactivated nitrogenase induced by O2. This mechanism further increases the iron use efficiency in Trichodesmium. Overall, our study provides mechanistic and quantitative insight into the diurnal iron allocation that can alleviate iron limitation to Trichodesmium.
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Kamada S, Nakajima Y, Shen JR. Structural insights into the action mechanisms of artificial electron acceptors in photosystem II. J Biol Chem 2023:104839. [PMID: 37209822 PMCID: PMC10300377 DOI: 10.1016/j.jbc.2023.104839] [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: 04/06/2023] [Revised: 05/07/2023] [Accepted: 05/15/2023] [Indexed: 05/22/2023] Open
Abstract
Photosystem II (PSII) utilizes light energy to split water, and the electrons extracted from water are transferred to QB, a plastoquinone (PQ) molecule bound to the D1 subunit of PSII. Many artificial electron acceptors (AEAs) with similar molecular structures to PQ can accept electrons from PSII. However, the molecular mechanism by which AEAs act on PSII is unclear. Here, we solved the crystal structure of PSII treated with three different AEAs, 2,5-dibromo-1,4-benzoquinone, 2,6-dichloro-1,4-benzoquinone, and 2-phenyl-1,4-benzoquinone, at 1.95-2.10 Å resolution. Our results show that all AEAs substitute for QB and are bound to the QB-binding site (QB site) to receive electrons, but their binding strengths are different, resulting in differences in their efficiencies to accept electrons. The acceptor 2-phenyl-1,4-benzoquinone binds most weakly to the QB site, and showed the highest oxygen-evolving activity, implying a reverse relationship between the binding strength and oxygen-evolving activity. In addition, a novel quinone binding site, designated the QD site, was discovered, which is located in the vicinity of QB site and close to QC site, a binding site reported previously. This QD site is expected to play a role as a channel or a storage site for quinones to be transported to the QB site. These results provide the structural basis for elucidating the actions of AEAs and exchange mechanism of QB in PSII, and also provide information for the design of more efficient electron acceptors.
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Affiliation(s)
- Shinji Kamada
- Faculty of Science, Okayama University, Okayama 700-8503, Japan
| | - Yoshiki Nakajima
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8503, Japan.
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8503, Japan.
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Svoboda V, Oung HMO, Koochak H, Yarbrough R, Mckenzie SD, Puthiyaveetil S, Kirchhoff H. Quantification of energy-converting protein complexes in plant thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148945. [PMID: 36442511 DOI: 10.1016/j.bbabio.2022.148945] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/15/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022]
Abstract
Knowledge about the exact abundance and ratio of photosynthetic protein complexes in thylakoid membranes is central to understanding structure-function relationships in energy conversion. Recent modeling approaches for studying light harvesting and electron transport reactions rely on quantitative information on the constituent complexes in thylakoid membranes. Over the last decades several quantitative methods have been established and refined, enabling precise stoichiometric information on the five main energy-converting building blocks in the thylakoid membrane: Light-harvesting complex II (LHCII), Photosystem II (PSII), Photosystem I (PSI), cytochrome b6f complex (cyt b6f complex), and ATPase. This paper summarizes a few quantitative spectroscopic and biochemical methods that are currently available for quantification of plant thylakoid protein complexes. Two new methods are presented for quantification of LHCII and the cyt b6f complex, which agree well with established methods. In addition, recent improvements in mass spectrometry (MS) allow deeper compositional information on thylakoid membranes. The comparison between mass spectrometric and more classical protein quantification methods shows similar quantities of complexes, confirming the potential of thylakoid protein complex quantification by MS. The quantitative information on PSII, PSI, and LHCII reveal that about one third of LHCII must be associated with PSI for a balanced light energy absorption by the two photosystems.
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Affiliation(s)
- Vaclav Svoboda
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Hui Min Olivia Oung
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Haniyeh Koochak
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Robert Yarbrough
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Steven D Mckenzie
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Sujith Puthiyaveetil
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
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14
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Ozawa SI, Buchert F, Reuys R, Hippler M, Takahashi Y. Algal PETC-Pro171-Leu suppresses electron transfer in cytochrome b6f under acidic lumenal conditions. PLANT PHYSIOLOGY 2023; 191:1803-1817. [PMID: 36516417 PMCID: PMC10022631 DOI: 10.1093/plphys/kiac575] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
Linear photosynthetic electron flow (LEF) produces NADPH and generates a proton electrochemical potential gradient across the thylakoid membrane to synthesize ATP, both of which are required for CO2 fixation. As cellular demand for ATP and NADPH varies, cyclic electron flow (CEF) between Photosystem I and the cytochrome b6f complex (b6f) produces extra ATP. b6f regulates LEF and CEF via photosynthetic control, which is a pH-dependent b6f slowdown of plastoquinol oxidation at the lumenal site. This protection mechanism is triggered at more alkaline lumen pH in the pgr1 (proton gradient regulation 1) mutant of the vascular plant Arabidopsis (Arabidopsis thaliana), which contains a Pro194Leu substitution in the b6f Rieske Iron-sulfur protein Photosynthetic Electron Transfer C (PETC) subunit. In this work, we introduced the equivalent pgr1 mutation in the green alga Chlamydomonas reinhardtii to generate PETC-P171L. Consistent with the pgr1 phenotype, PETC-P171L displayed impaired NPQ induction along with slower photoautotrophic growth under high light conditions. Our data provide evidence that the ΔpH component in PETC-P171L depends on oxygen availability. Only under low oxygen conditions was the ΔpH component sufficient to trigger a phenotype in algal PETC-P171L where the mutant b6f was more restricted to oxidize the plastoquinol pool and showed diminished electron flow through the b6f complex. These results demonstrate that photosynthetic control of different stringency are established in C. reinhardtii depending on the cellular metabolism, and the lumen pH-sensitive PETC-P171L was generated to read out various associated effects.
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Affiliation(s)
| | - Felix Buchert
- Institute of Plant Biology and Biotechnology, University of Münster, 48143 Münster, Germany
| | - Ruby Reuys
- Institute of Plant Biology and Biotechnology, University of Münster, 48143 Münster, Germany
| | - Michael Hippler
- Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan
- Institute of Plant Biology and Biotechnology, University of Münster, 48143 Münster, Germany
| | - Yuichiro Takahashi
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
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15
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Zhan J, Xia D. Bcs1, a novel target for fungicide. Front Chem 2023; 11:1146753. [PMID: 36993815 PMCID: PMC10040684 DOI: 10.3389/fchem.2023.1146753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/03/2023] [Indexed: 03/14/2023] Open
Abstract
The mitochondrial respiratory chain has long been a primary target for the development of fungicides for its indispensable role in various cellular functions including energy metabolism. Over the years, a wide range of natural and synthetic fungicides and pesticides targeting the respiratory chain complexes have been discovered or developed and used in agriculture and in medicine, which brought considerable economic gains but was also accompanied by the emergence of resistance to these compounds. To delay and overcome the onset of resistance, novel targets for fungicides development are actively being pursued. Mitochondrial AAA protein Bcs1 is necessary for the biogenesis of respiratory chain Complex III, also known as cyt bc1 complex, by delivering the last essential iron-sulfur protein subunit in its folded form to the cyt bc1 precomplex. Although no report on the phenotypes of knock-out Bcs1 has been reported in animals, pathogenic Bcs1 mutations cause Complex III deficiency and respiratory growth defects, which makes it a promising new target for the development of fungicides. Recent Cryo-EM and X-ray structures of mouse and yeast Bcs1 revealed the basic oligomeric states of Bcs1, shed light on the translocation mechanism of its substrate ISP, and provided the basis for structure-based drug design. This review summarizes the recent progress made on understanding the structure and function of Bcs1, proposes the use of Bcs1 as an antifungal target, and provides novel prospects for fungicides design by targeting Bcs1.
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16
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Sarewicz M, Szwalec M, Pintscher S, Indyka P, Rawski M, Pietras R, Mielecki B, Koziej Ł, Jaciuk M, Glatt S, Osyczka A. High-resolution cryo-EM structures of plant cytochrome b 6f at work. SCIENCE ADVANCES 2023; 9:eadd9688. [PMID: 36638176 PMCID: PMC9839326 DOI: 10.1126/sciadv.add9688] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
Plants use solar energy to power cellular metabolism. The oxidation of plastoquinol and reduction of plastocyanin by cytochrome b6f (Cyt b6f) is known as one of the key steps of photosynthesis, but the catalytic mechanism in the plastoquinone oxidation site (Qp) remains elusive. Here, we describe two high-resolution cryo-EM structures of the spinach Cyt b6f homodimer with endogenous plastoquinones and in complex with plastocyanin. Three plastoquinones are visible and line up one after another head to tail near Qp in both monomers, indicating the existence of a channel in each monomer. Therefore, quinones appear to flow through Cyt b6f in one direction, transiently exposing the redox-active ring of quinone during catalysis. Our work proposes an unprecedented one-way traffic model that explains efficient quinol oxidation during photosynthesis and respiration.
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Affiliation(s)
- Marcin Sarewicz
- Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Mateusz Szwalec
- Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Sebastian Pintscher
- Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
- Małopolska Centre of Biotechnology (MCB), Jagiellonian University, Kraków, Poland
| | - Paulina Indyka
- Małopolska Centre of Biotechnology (MCB), Jagiellonian University, Kraków, Poland
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Kraków, Poland
| | - Michał Rawski
- Małopolska Centre of Biotechnology (MCB), Jagiellonian University, Kraków, Poland
| | - Rafał Pietras
- Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Bohun Mielecki
- Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Łukasz Koziej
- Małopolska Centre of Biotechnology (MCB), Jagiellonian University, Kraków, Poland
| | - Marcin Jaciuk
- Małopolska Centre of Biotechnology (MCB), Jagiellonian University, Kraków, Poland
| | - Sebastian Glatt
- Małopolska Centre of Biotechnology (MCB), Jagiellonian University, Kraków, Poland
| | - Artur Osyczka
- Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
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17
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Li N, Wong WS, Feng L, Wang C, Wong KS, Zhang N, Yang W, Jiang Y, Jiang L, He JX. The thylakoid membrane protein NTA1 is an assembly factor of the cytochrome b 6f complex essential for chloroplast development in Arabidopsis. PLANT COMMUNICATIONS 2023; 4:100509. [PMID: 36560880 PMCID: PMC9860185 DOI: 10.1016/j.xplc.2022.100509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/18/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
The cytochrome b6f (Cyt b6f) complex is a multisubunit protein complex in chloroplast thylakoid membranes required for photosynthetic electron transport. Here we report the isolation and characterization of the new tiny albino 1 (nta1) mutant in Arabidopsis, which has severe defects in Cyt b6f accumulation and chloroplast development. Gene cloning revealed that the nta1 phenotype was caused by disruption of a single nuclear gene, NTA1, which encodes an integral thylakoid membrane protein conserved across green algae and plants. Overexpression of NTA1 completely rescued the nta1 phenotype, and knockout of NTA1 in wild-type plants recapitulated the mutant phenotype. Loss of NTA1 function severely impaired the accumulation of multiprotein complexes related to photosynthesis in thylakoid membranes, particularly the components of Cyt b6f. NTA1 was shown to directly interact with four subunits (Cyt b6/PetB, PetD, PetG, and PetN) of Cyt b6f through the DUF1279 domain and C-terminal sequence to mediate their assembly. Taken together, our results identify NTA1 as a new and key regulator of chloroplast development that plays essential roles in assembly of the Cyt b6f complex by interacting with multiple Cyt b6f subunits.
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Affiliation(s)
- Na Li
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Wing Shing Wong
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Lei Feng
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Chunming Wang
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - King Shing Wong
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Nianhui Zhang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Wei Yang
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Yueming Jiang
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Core Botanical Gardens, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Liwen Jiang
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Jun-Xian He
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
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18
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Zhang S, Zou B, Cao P, Su X, Xie F, Pan X, Li M. Structural insights into photosynthetic cyclic electron transport. MOLECULAR PLANT 2023; 16:187-205. [PMID: 36540023 DOI: 10.1016/j.molp.2022.12.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/17/2022] [Accepted: 12/18/2022] [Indexed: 06/17/2023]
Abstract
During photosynthesis, light energy is utilized to drive sophisticated biochemical chains of electron transfers, converting solar energy into chemical energy that feeds most life on earth. Cyclic electron transfer/flow (CET/CEF) plays an essential role in efficient photosynthesis, as it balances the ATP/NADPH ratio required in various regulatory and metabolic pathways. Photosystem I, cytochrome b6f, and NADH dehydrogenase (NDH) are large multisubunit protein complexes embedded in the thylakoid membrane of the chloroplast and key players in NDH-dependent CEF pathway. Furthermore, small mobile electron carriers serve as shuttles for electrons between these membrane protein complexes. Efficient electron transfer requires transient interactions between these electron donors and acceptors. Structural biology has been a powerful tool to advance our knowledge of this important biological process. A number of structures of the membrane-embedded complexes, soluble electron carrier proteins, and transient complexes composed of both have now been determined. These structural data reveal detailed interacting patterns of these electron donor-acceptor pairs, thus allowing us to visualize the different parts of the electron transfer process. This review summarizes the current state of structural knowledge of three membrane complexes and their interaction patterns with mobile electron carrier proteins.
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Affiliation(s)
- Shumeng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Baohua Zou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Peng Cao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Xiaodong Su
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Fen Xie
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Xiaowei Pan
- College of Life Science, Capital Normal University, Beijing, China
| | - Mei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
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19
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Kishimoto H, Azai C, Yamamoto T, Mutoh R, Nakaniwa T, Tanaka H, Miyanoiri Y, Kurisu G, Oh-oka H. Soluble domains of cytochrome c-556 and Rieske iron-sulfur protein from Chlorobaculum tepidum: Crystal structures and interaction analysis. Curr Res Struct Biol 2023; 5:100101. [PMID: 37180033 PMCID: PMC10172866 DOI: 10.1016/j.crstbi.2023.100101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 05/15/2023] Open
Abstract
In photosynthetic green sulfur bacteria, the electron transfer reaction from menaquinol:cytochrome c oxidoreductase to the P840 reaction center (RC) complex occurs directly without any involvement of soluble electron carrier protein(s). X-ray crystallography has determined the three-dimensional structures of the soluble domains of the CT0073 gene product and Rieske iron-sulfur protein (ISP). The former is a mono-heme cytochrome c with an α-absorption peak at 556 nm. The overall fold of the soluble domain of cytochrome c-556 (designated as cyt c-556sol) consists of four α-helices and is very similar to that of water-soluble cyt c-554 that independently functions as an electron donor to the P840 RC complex. However, the latter's remarkably long and flexible loop between the α3 and α4 helices seems to make it impossible to be a substitute for the former. The structure of the soluble domain of the Rieske ISP (Rieskesol protein) shows a typical β-sheets-dominated fold with a small cluster-binding and a large subdomain. The architecture of the Rieskesol protein is bilobal and belongs to those of b6f-type Rieske ISPs. Nuclear magnetic resonance (NMR) measurements revealed weak non-polar but specific interaction sites on Rieskesol protein when mixed with cyt c-556sol. Therefore, menaquinol:cytochrome c oxidoreductase in green sulfur bacteria features a Rieske/cytb complex tightly associated with membrane-anchored cyt c-556.
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Affiliation(s)
- Hiraku Kishimoto
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Chihiro Azai
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Tomoya Yamamoto
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Risa Mutoh
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Tetsuko Nakaniwa
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Hideaki Tanaka
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Yohei Miyanoiri
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
- Corresponding author.
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
- Corresponding author.
| | - Hirozo Oh-oka
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
- Center for Education in Liberal Arts and Sciences, Osaka University, Toyonaka, Osaka, 560-0043, Japan
- Corresponding author. Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
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20
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Wieferig JP, Kühlbrandt W. Analysis of the conformational heterogeneity of the Rieske iron-sulfur protein in complex III 2 by cryo-EM. IUCRJ 2023; 10:27-37. [PMID: 36598500 PMCID: PMC9812224 DOI: 10.1107/s2052252522010570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023]
Abstract
Movement of the Rieske domain of the iron-sulfur protein is essential for intramolecular electron transfer within complex III2 (CIII2) of the respiratory chain as it bridges a gap in the cofactor chain towards the electron acceptor cytochrome c. We present cryo-EM structures of CIII2 from Yarrowia lipolytica at resolutions up to 2.0 Å under different conditions, with different redox states of the cofactors of the high-potential chain. All possible permutations of three primary positions were observed, indicating that the two halves of the dimeric complex act independently. Addition of the substrate analogue decylubiquinone to CIII2 with a reduced high-potential chain increased the occupancy of the Qo site. The extent of Rieske domain interactions through hydrogen bonds to the cytochrome b and cytochrome c1 subunits varied depending on the redox state and substrate. In the absence of quinols, the reduced Rieske domain interacted more closely with cytochrome b and cytochrome c1 than in the oxidized state. Upon addition of the inhibitor antimycin A, the heterogeneity of the cd1-helix and ef-loop increased, which may be indicative of a long-range effect on the Rieske domain.
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Affiliation(s)
- Jan-Philip Wieferig
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
| | - Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
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21
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Manoj KM, Gideon DA, Parashar A, Nirusimhan V, Annadurai P, Jacob VD, Manekkathodi A. Validating the predictions of murburn model for oxygenic photosynthesis: Analyses of ligand-binding to protein complexes and cross-system comparisons. J Biomol Struct Dyn 2022; 40:11024-11056. [PMID: 34328391 DOI: 10.1080/07391102.2021.1953607] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this second half of our treatise on oxygenic photosynthesis, we provide support for the murburn model of the light reaction of photosynthesis and ratify key predictions made in the first part. Molecular docking and visualization of various ligands of quinones/quinols (and their derivatives) with PS II/Cytochrome b6f complexes did not support chartered 2e-transport role of quinols. A broad variety of herbicides did not show any affinity/binding-based rationales for inhibition of photosynthesis. We substantiate the proposal that disubstituted phenolics (perceived as protonophores/uncouplers or affinity-based inhibitors in the classical purview) serve as interfacial modulators of diffusible reactive (oxygen) species or DR(O)S. The DRS-based murburn model is evidenced by the identification of multiple ADP-binding sites on the extra-membraneous projection of protein complexes and structure/distribution of the photo/redox catalysts. With a panoramic comparison of the redox metabolic machinery across diverse organellar/cellular systems, we highlight the ubiquitous one-electron murburn facets (cofactors of porphyrin, flavin, FeS, other metal centers and photo/redox active pigments) that enable a facile harnessing of the utility of DRS. In the summative analyses, it is demonstrated that the murburn model of light reaction explains the structures of membrane supercomplexes recently observed in thylakoids and also accounts for several photodynamic experimental observations and evolutionary considerations. In toto, the work provides a new orientation and impetus to photosynthesis research. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kelath Murali Manoj
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Daniel Andrew Gideon
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Abhinav Parashar
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Vijay Nirusimhan
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Pushparaj Annadurai
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Vivian David Jacob
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Afsal Manekkathodi
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
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22
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Manoj KM, Bazhin NM, Jacob VD, Parashar A, Gideon DA, Manekkathodi A. Structure-function correlations and system dynamics in oxygenic photosynthesis: classical perspectives and murburn precepts. J Biomol Struct Dyn 2022; 40:10997-11023. [PMID: 34323659 DOI: 10.1080/07391102.2021.1953606] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
HIGHLIGHTS Contemporary beliefs on oxygenic photosynthesis are critiqued.Murburn model is suggested as an alternative explanation.In the new model, diffusible reactive species are the main protagonists.All pigments are deemed photo-redox active in the new stochastic mechanism.NADPH synthesis occurs via simple electron transfers, not via elaborate ETC.Oxygenesis is delocalized and not just centered at Mn-Complex.Energetics of murburn proposal for photophosphorylation is provided.The proposal ushers in a paradigm shift in photosynthesis research.
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Affiliation(s)
| | | | - Vivian David Jacob
- Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India
| | - Abhinav Parashar
- Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India
| | | | - Afsal Manekkathodi
- Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India
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23
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Integrated Transcriptome and Metabolome Analysis Reveals Phenylpropanoid Biosynthesis and Phytohormone Signaling Contribute to " Candidatus Liberibacter asiaticus" Accumulation in Citrus Fruit Piths (Fluffy Albedo). Int J Mol Sci 2022; 23:ijms232415648. [PMID: 36555287 PMCID: PMC9779719 DOI: 10.3390/ijms232415648] [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: 10/31/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
"Candidatus Liberibacter asiaticus" (CLas) is a phloem-restricted α-proteobacterium that is associated with citrus huanglongbing (HLB), which is the most destructive disease that affects all varieties of citrus. Although midrib is usually used as a material for CLas detection, we recently found that the bacterium was enriched in fruits, especially in the fruit pith. However, no study has revealed the molecular basis of these two parts in responding to CLas infection. Therefore, we performed transcriptome and UHPLC-MS-based targeted and untargeted metabolomics analyses in order to organize the essential genes and metabolites that are involved. Transcriptome and metabolome characterized 4834 differentially expressed genes (DEGs) and 383 differentially accumulated metabolites (DAMs) between the two materials, wherein 179 DEGs and 44 DAMs were affected by HLB in both of the tissues, involving the pathways of phenylpropanoid biosynthesis, phytohormone signaling transduction, starch and sucrose metabolism, and photosynthesis. Notably, we discovered that the gene expression that is related to beta-glucosidase and endoglucanase was up-regulated in fruits. In addition, defense-related gene expression and metabolite accumulation were significantly down-regulated in infected fruits. Taken together, the decreased amount of jasmonic acid, coupled with the reduced accumulation of phenylpropanoid and the increased proliferation of indole-3-acetic acid, salicylic acid, and abscisic acid, compared to leaf midribs, may contribute largely to the enrichment of CLas in fruit piths, resulting in disorders of photosynthesis and starch and sucrose metabolism.
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24
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Vergara-Barros P, Alcorta J, Casanova-Katny A, Nürnberg DJ, Díez B. Compensatory Transcriptional Response of Fischerella thermalis to Thermal Damage of the Photosynthetic Electron Transfer Chain. Molecules 2022; 27:8515. [PMID: 36500606 PMCID: PMC9740203 DOI: 10.3390/molecules27238515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 12/11/2022] Open
Abstract
Key organisms in the environment, such as oxygenic photosynthetic primary producers (photosynthetic eukaryotes and cyanobacteria), are responsible for fixing most of the carbon globally. However, they are affected by environmental conditions, such as temperature, which in turn affect their distribution. Globally, the cyanobacterium Fischerella thermalis is one of the main primary producers in terrestrial hot springs with thermal gradients up to 60 °C, but the mechanisms by which F. thermalis maintains its photosynthetic activity at these high temperatures are not known. In this study, we used molecular approaches and bioinformatics, in addition to photophysiological analyses, to determine the genetic activity associated with the energy metabolism of F. thermalis both in situ and in high-temperature (40 °C to 65 °C) cultures. Our results show that photosynthesis of F. thermalis decays with temperature, while increased transcriptional activity of genes encoding photosystem II reaction center proteins, such as PsbA (D1), could help overcome thermal damage at up to 60 °C. We observed that F. thermalis tends to lose copies of the standard G4 D1 isoform while maintaining the recently described D1INT isoform, suggesting a preference for photoresistant isoforms in response to the thermal gradient. The transcriptional activity and metabolic characteristics of F. thermalis, as measured by metatranscriptomics, further suggest that carbon metabolism occurs in parallel with photosynthesis, thereby assisting in energy acquisition under high temperatures at which other photosynthetic organisms cannot survive. This study reveals that, to cope with the harsh conditions of hot springs, F. thermalis has several compensatory adaptations, and provides emerging evidence for mixotrophic metabolism as being potentially relevant to the thermotolerance of this species. Ultimately, this work increases our knowledge about thermal adaptation strategies of cyanobacteria.
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Affiliation(s)
- Pablo Vergara-Barros
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago 8331150, Chile
- Millennium Institute Center for Genome Regulation (CGR), Santiago 8370186, Chile
| | - Jaime Alcorta
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago 8331150, Chile
| | - Angélica Casanova-Katny
- Laboratory of Plant Ecophysiology, Faculty of Natural Resources, Campus Luis Rivas del Canto, Catholic University of Temuco, Temuco 4780000, Chile
| | - Dennis J. Nürnberg
- Institute of Experimental Physics, Freie Universität Berlin, 14195 Berlin, Germany
- Dahlem Centre of Plant Sciences, Freie Universität Berlin, 14195 Berlin, Germany
| | - Beatriz Díez
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago 8331150, Chile
- Millennium Institute Center for Genome Regulation (CGR), Santiago 8370186, Chile
- Center for Climate and Resilience Research (CR)2, Santiago 8370449, Chile
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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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26
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Joliot P, Sellés J, Wollman FA, Verméglio A. High efficient cyclic electron flow and functional supercomplexes in Chlamydomonas cells. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148909. [PMID: 35952798 DOI: 10.1016/j.bbabio.2022.148909] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
A very high rate for cyclic electron flow (CEF) around PSI (~180 s-1 or 210 s-1 in minimum medium or in the presence of a carbon source respectively) is measured in the presence of methyl viologen (MV) in intact cells of Chlamydomonas reinhardtii under anaerobic conditions. The observation of an efficient CEF in the presence of methyl viologen is in agreement with the previous results reports of Asada et al. in broken chloroplasts (Plant Cell Physiol. 31(4) (1990) 557-564). From the analysis of the P700 and PC absorbance changes, we propose that a confinement between 2 PC molecules, 1 PSI and 1 cytb6f corresponding to a functional supercomplex is responsible for these high rates of CEF. Supercomplex formation is also observed in the absence of methyl viologen, but with lower maximal CEF rate (about 100 s-1) suggesting that this compound facilitates the mediation of electron transfer from PSI acceptors to the stromal side of cytb6f. Further analysis of CEF in mutants of Chlamydomonas defective in state transitions shows the requirement of a kinase-driven transition to state 2 to establish this functional supercomplex configuration. However, a movement of the LHCII antennae is not involved in this process. We discuss the possible involvement of auxiliary proteins, among which is a small cytb6f-associated polypeptide, the PETO protein, which is one of the targets of the STT7 kinase.
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Affiliation(s)
- Pierre Joliot
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Microalgues, Institut de Biologie Physico-Chimique, CNRS UMR 7141, Sorbonne Université, Paris, France.
| | - Julien Sellés
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Microalgues, Institut de Biologie Physico-Chimique, CNRS UMR 7141, Sorbonne Université, Paris, France.
| | - Françis-André Wollman
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Microalgues, Institut de Biologie Physico-Chimique, CNRS UMR 7141, Sorbonne Université, Paris, France
| | - André Verméglio
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Microalgues, Institut de Biologie Physico-Chimique, CNRS UMR 7141, Sorbonne Université, Paris, France
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27
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Ustynyuk LY, Tikhonov AN. Plastoquinol Oxidation: Rate-Limiting Stage in the Electron Transport Chain of Chloroplasts. BIOCHEMISTRY (MOSCOW) 2022; 87:1084-1097. [DOI: 10.1134/s0006297922100029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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28
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Banh ATM, Thiele B, Chlubek A, Hombach T, Kleist E, Matsubara S. Combination of long-term 13CO 2 labeling and isotopolog profiling allows turnover analysis of photosynthetic pigments in Arabidopsis leaves. PLANT METHODS 2022; 18:114. [PMID: 36183136 PMCID: PMC9526918 DOI: 10.1186/s13007-022-00946-3] [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: 02/28/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Living cells maintain and adjust structural and functional integrity by continual synthesis and degradation of metabolites and macromolecules. The maintenance and adjustment of thylakoid membrane involve turnover of photosynthetic pigments along with subunits of protein complexes. Quantifying their turnover is essential to understand the mechanisms of homeostasis and long-term acclimation of photosynthetic apparatus. Here we report methods combining whole-plant long-term 13CO2 labeling and liquid chromatography - mass spectrometry (LC-MS) analysis to determine the size of non-labeled population (NLP) of carotenoids and chlorophylls (Chl) in leaf pigment extracts of partially 13C-labeled plants. RESULTS The labeling chamber enabled parallel 13CO2 labeling of up to 15 plants of Arabidopsis thaliana with real-time environmental monitoring ([CO2], light intensity, temperature, relative air humidity and pressure) and recording. No significant difference in growth or photosynthetic pigment composition was found in leaves after 7-d exposure to normal CO2 (~ 400 ppm) or 13CO2 in the labeling chamber, or in ambient air outside the labeling chamber (control). Following chromatographic separation of the pigments and mass peak assignment by high-resolution Fourier-transform ion cyclotron resonance MS, mass spectra of photosynthetic pigments were analyzed by triple quadrupole MS to calculate NLP. The size of NLP remaining after the 7-d 13CO2 labeling was ~ 10.3% and ~ 11.5% for all-trans- and 9-cis-β-carotene, ~ 21.9% for lutein, ~ 18.8% for Chl a and 33.6% for Chl b, highlighting non-uniform turnover of these pigments in thylakoids. Comparable results were obtained in all replicate plants of the 13CO2 labeling experiment except for three that were showing anthocyanin accumulation and growth impairment due to insufficient water supply (leading to stomatal closure and less 13C incorporation). CONCLUSIONS Our methods allow 13CO2 labeling and estimation of NLP for photosynthetic pigments with high reproducibility despite potential variations in [13CO2] between the experiments. The results indicate distinct turnover rates of carotenoids and Chls in thylakoid membrane, which can be investigated in the future by time course experiments. Since 13C enrichment can be measured in a range of compounds, long-term 13CO2 labeling chamber, in combination with appropriate MS methods, facilitates turnover analysis of various metabolites and macromolecules in plants on a time scale of hours to days.
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Affiliation(s)
- Anh Thi-Mai Banh
- IBG-2: Plant Sciences, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Björn Thiele
- IBG-2: Plant Sciences, Forschungszentrum Jülich, 52425, Jülich, Germany
- IBG-3: Agrosphere, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Antonia Chlubek
- IBG-2: Plant Sciences, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Thomas Hombach
- IBG-2: Plant Sciences, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Einhard Kleist
- IBG-2: Plant Sciences, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Shizue Matsubara
- IBG-2: Plant Sciences, Forschungszentrum Jülich, 52425, Jülich, Germany.
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Structure of cyanobacterial photosystem I complexed with ferredoxin at 1.97 Å resolution. Commun Biol 2022; 5:951. [PMID: 36097054 PMCID: PMC9467995 DOI: 10.1038/s42003-022-03926-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/30/2022] [Indexed: 11/25/2022] Open
Abstract
Photosystem I (PSI) is a light driven electron pump transferring electrons from Cytochrome c6 (Cyt c6) to Ferredoxin (Fd). An understanding of this electron transfer process is hampered by a paucity of structural detail concerning PSI:Fd interface and the possible binding sites of Cyt c6. Here we describe the high resolution cryo-EM structure of Thermosynechococcus elongatus BP-1 PSI in complex with Fd and a loosely bound Cyt c6. Side chain interactions at the PSI:Fd interface including bridging water molecules are visualized in detail. The structure explains the properties of mutants of PsaE and PsaC that affect kinetics of Fd binding and suggests a molecular switch for the dissociation of Fd upon reduction. Calorimetry-based thermodynamic analyses confirms a single binding site for Fd and demonstrates that PSI:Fd complexation is purely driven by entropy. A possible reaction cycle for the efficient transfer of electrons from Cyt c6 to Fd via PSI is proposed. In order to aid the understanding of the electron transfer process within the cyanobacterial photosystem I, its structure - when complexed with Ferredoxin - is determined at 1.97 Å resolution.
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30
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Prospects of cyanobacterial pigment production: biotechnological potential and optimization strategies. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Proctor MS, Morey-Burrows FS, Canniffe DP, Martin EC, Swainsbury DJK, Johnson MP, Hunter CN, Sutherland GA, Hitchcock A. Zeta-Carotene Isomerase (Z-ISO) Is Required for Light-Independent Carotenoid Biosynthesis in the Cyanobacterium Synechocystis sp. PCC 6803. Microorganisms 2022; 10:microorganisms10091730. [PMID: 36144332 PMCID: PMC9505123 DOI: 10.3390/microorganisms10091730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/19/2022] [Accepted: 08/21/2022] [Indexed: 11/16/2022] Open
Abstract
Carotenoids are crucial photosynthetic pigments utilized for light harvesting, energy transfer, and photoprotection. Although most of the enzymes involved in carotenoid biosynthesis in chlorophototrophs are known, some are yet to be identified or fully characterized in certain organisms. A recently characterized enzyme in oxygenic phototrophs is 15-cis-zeta(ζ)-carotene isomerase (Z-ISO), which catalyzes the cis-to-trans isomerization of the central 15–15′ cis double bond in 9,15,9′-tri-cis-ζ-carotene to produce 9,9′-di-cis-ζ-carotene during the four-step conversion of phytoene to lycopene. Z-ISO is a heme B-containing enzyme best studied in angiosperms. Homologs of Z-ISO are present in organisms that use the multi-enzyme poly-cis phytoene desaturation pathway, including algae and cyanobacteria, but appear to be absent in green bacteria. Here we confirm the identity of Z-ISO in the model unicellular cyanobacterium Synechocystis sp. PCC 6803 by showing that the protein encoded by the slr1599 open reading frame has ζ-carotene isomerase activity when produced in Escherichia coli. A Synechocystis Δslr1599 mutant synthesizes a normal quota of carotenoids when grown under illumination, where the photolabile 15–15′ cis double bond of 9,15,9′-tri-cis-ζ-carotene is isomerized by light, but accumulates this intermediate and fails to produce ‘mature’ carotenoid species during light-activated heterotrophic growth, demonstrating the requirement of Z-ISO for carotenoid biosynthesis during periods of darkness. In the absence of a structure of Z-ISO, we analyze AlphaFold models of the Synechocystis, Zea mays (maize), and Arabidopsis thaliana enzymes, identifying putative protein ligands for the heme B cofactor and the substrate-binding site.
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Affiliation(s)
- Matthew S. Proctor
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Correspondence: (M.S.P.); (G.A.S.); (A.H.)
| | | | - Daniel P. Canniffe
- Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool L69 7BE, UK
| | | | - David J. K. Swainsbury
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | | | - C. Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - George A. Sutherland
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Correspondence: (M.S.P.); (G.A.S.); (A.H.)
| | - Andrew Hitchcock
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Correspondence: (M.S.P.); (G.A.S.); (A.H.)
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Lukeš V, Kováčová A, Hartmann H. On thermodynamics of electron, proton and PCET processes of catechol, hydroquinone and resorcinol – Consequences for redox properties of polyphenolic compounds. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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33
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Ko SR, Jeong Y, Cho SH, Lee E, Jeong BS, Baek SH, Oh BH, Ahn CY, Oh HM, Cho BK, Cho S. Functional role of a novel algicidal compound produced by Pseudoruegeria sp. M32A2M on the harmful algae Alexandrium catenella. CHEMOSPHERE 2022; 300:134535. [PMID: 35405190 DOI: 10.1016/j.chemosphere.2022.134535] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 03/12/2022] [Accepted: 04/04/2022] [Indexed: 06/14/2023]
Abstract
A marine phytoplankton dinoflagellate, Alexandrium sp. is known to cause worldwide harmful algal blooms, resulting in paralytic shellfish poisoning. In this study, we isolated a novel compound secreted by the marine bacterium Pseudoruegeria sp. M32A2M, and showed that it displays algicidal activity against A. catenella (group I). The molecular structure of the compound was analyzed by using 1H nuclear magnetic resonance (NMR), 13C NMR, and gas chromatography-mass spectrometry, which revealed that the compound was a diketopiperazine, cyclo[Ala-Gly]. Cyclo[Ala-Gly] induced a rapid decrease in the active chlorophyll a content and maximal quantum yield of photosystem II, leading to membrane disintegration after 24 h of its treatment. It showed the highest algicidal effect against diketopiperazines and also showed specific algicidal activities against several dinoflagellate species, but not for diatom species. In particular, cyclo[Ala-Gly] caused the transcriptional downregulation of the photosynthesis-related membrane complex in A. catenella, but not in the diatom Chaetoceros simplex. Based on structural modeling, we elucidated that cyclo[Ala-Gly] has a structure similar to that of plastoquinone, which transfers electrons by binding to the photosystem II core proteins PsbA and PsbD. This suggests a novel role for cyclo[Ala-Gly] as a potential inhibitor of photosynthesis.
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Affiliation(s)
- So-Ra Ko
- Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Yujin Jeong
- Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Sang-Hyeok Cho
- Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Eunju Lee
- Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Bo-Seong Jeong
- Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Seung Ho Baek
- Risk Assessment Research Center, Korea Institute of Ocean Science and Technology, Geoje, 53201, Republic of Korea
| | - Byung-Ha Oh
- Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Chi-Yong Ahn
- Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Hee-Mock Oh
- Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea.
| | - Byung-Kwan Cho
- Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| | - Suhyung Cho
- Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
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Sandoval-Ibáñez O, Rolo D, Ghandour R, Hertle AP, Armarego-Marriott T, Sampathkumar A, Zoschke R, Bock R. De-etiolation-induced protein 1 (DEIP1) mediates assembly of the cytochrome b 6f complex in Arabidopsis. Nat Commun 2022; 13:4045. [PMID: 35831297 PMCID: PMC9279372 DOI: 10.1038/s41467-022-31758-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 07/01/2022] [Indexed: 11/26/2022] Open
Abstract
The conversion of light energy to chemical energy by photosynthesis requires the concerted action of large protein complexes in the thylakoid membrane. Recent work has provided fundamental insights into the three-dimensional structure of these complexes, but how they are assembled from hundreds of parts remains poorly understood. Particularly little is known about the biogenesis of the cytochrome b6f complex (Cytb6f), the redox-coupling complex that interconnects the two photosystems. Here we report the identification of a factor that guides the assembly of Cytb6f in thylakoids of chloroplasts. The protein, DE-ETIOLATION-INDUCED PROTEIN 1 (DEIP1), resides in the thylakoid membrane and is essential for photoautotrophic growth. Knock-out mutants show a specific loss of Cytb6f, and are defective in complex assembly. We demonstrate that DEIP1 interacts with the two cytochrome subunits of the complex, PetA and PetB, and mediates the assembly of intermediates in Cytb6f biogenesis. The identification of DEIP1 provides an entry point into the study of the assembly pathway of a crucial complex in photosynthetic electron transfer. The Cytb6f complex is a multi-subunit enzyme that couples the two photosystems during the light reactions of photosynthesis. Here the authors show that the thylakoid-localized DEIP1 protein interacts with the PetA and PetB subunits, and is essential for Cytb6f complex assembly in Arabidopsis.
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Affiliation(s)
- Omar Sandoval-Ibáñez
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - David Rolo
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Rabea Ghandour
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Alexander P Hertle
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Tegan Armarego-Marriott
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Arun Sampathkumar
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
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Mukherjee M, Geeta A, Ghosh S, Prusty A, Dutta S, Sarangi AN, Behera S, Adhikary SP, Tripathy S. Genome Analysis Coupled With Transcriptomics Reveals the Reduced Fitness of a Hot Spring Cyanobacterium Mastigocladus laminosus UU774 Under Exogenous Nitrogen Supplement. Front Microbiol 2022; 13:909289. [PMID: 35847102 PMCID: PMC9284123 DOI: 10.3389/fmicb.2022.909289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
The present study focuses on the stress response of a filamentous, AT-rich, heterocystous cyanobacterium Mastigocladus laminosus UU774, isolated from a hot spring, Taptapani, located in the eastern part of India. The genome of UU774 contains an indispensable fragment, scaffold_38, of unknown origin that is implicated during severe nitrogen and nutrition stress. Prolonged exposure to nitrogen compounds during starvation has profound adverse effects on UU774, leading to loss of mobility, loss of ability to fight pathogens, reduced cell division, decreased nitrogen-fixing ability, reduced ability to form biofilms, reduced photosynthetic and light-sensing ability, and reduced production of secreted effectors and chromosomal toxin genes, among others. Among genes showing extreme downregulation when grown in a medium supplemented with nitrogen with the fold change > 5 are transcriptional regulator gene WalR, carbonic anhydrases, RNA Polymerase Sigma F factor, fimbrial protein, and twitching mobility protein. The reduced expression of key enzymes involved in the uptake of phosphate and enzymes protecting oxygen-sensitive nitrogenases is significant during the presence of nitrogen. UU774 is presumed to withstand heat by overexpressing peptidases that may be degrading abnormally folded proteins produced during heat. The absence of a key gene responsible for heterocyst pattern formation, patS, and an aberrant hetN without a functional motif probably lead to the formation of a chaotic heterocyst pattern in UU774. We suggest that UU774 has diverged from Fischerella sp. PCC 9339, another hot spring species isolated in the United States.
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Affiliation(s)
- Mayuri Mukherjee
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Aribam Geeta
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Samrat Ghosh
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Asharani Prusty
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Subhajeet Dutta
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Aditya Narayan Sarangi
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
| | - Smrutisanjita Behera
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
| | | | - Sucheta Tripathy
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
- *Correspondence: Sucheta Tripathy ;
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Cryo-EM structures of the Synechocystis sp. PCC 6803 cytochrome b6f complex with and without the regulatory PetP subunit. Biochem J 2022; 479:1487-1503. [PMID: 35726684 PMCID: PMC9342900 DOI: 10.1042/bcj20220124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 06/01/2022] [Accepted: 06/21/2022] [Indexed: 11/17/2022]
Abstract
In oxygenic photosynthesis, the cytochrome b6f (cytb6f) complex links the linear electron transfer (LET) reactions occurring at photosystems I and II and generates a transmembrane proton gradient via the Q-cycle. In addition to this central role in LET, cytb6f also participates in a range of processes including cyclic electron transfer (CET), state transitions and photosynthetic control. Many of the regulatory roles of cytb6f are facilitated by auxiliary proteins that differ depending upon the species, yet because of their weak and transient nature the structural details of these interactions remain unknown. An apparent key player in the regulatory balance between LET and CET in cyanobacteria is PetP, a ∼10 kDa protein that is also found in red algae but not in green algae and plants. Here, we used cryogenic electron microscopy to determine the structure of the Synechocystis sp. PCC 6803 cytb6f complex in the presence and absence of PetP. Our structures show that PetP interacts with the cytoplasmic side of cytb6f, displacing the C-terminus of the PetG subunit and shielding the C-terminus of cytochrome b6, which binds the heme cn cofactor that is suggested to mediate CET. The structures also highlight key differences in the mode of plastoquinone binding between cyanobacterial and plant cytb6f complexes, which we suggest may reflect the unique combination of photosynthetic and respiratory electron transfer in cyanobacterial thylakoid membranes. The structure of cytb6f from a model cyanobacterial species amenable to genetic engineering will enhance future site-directed mutagenesis studies of structure-function relationships in this crucial ET complex.
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Impact of Ferrous Sulfate on Thylakoidal Multiprotein Complexes, Metabolism and Defence of Brassica juncea L. under Arsenic Stress. PLANTS 2022; 11:plants11121559. [PMID: 35736711 PMCID: PMC9228442 DOI: 10.3390/plants11121559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/02/2022] [Accepted: 06/08/2022] [Indexed: 11/17/2022]
Abstract
Forty-day-old Brassica juncea (var. Pusa Jai Kisan) plants were exposed to arsenic (As, 250 µM Na2HAsO4·7H2O) stress. The ameliorative role of ferrous sulfate (2 mM, FeSO4·7H2O, herein FeSO4) was evaluated at 7 days after treatment (7 DAT) and 14 DAT. Whereas, As induced high magnitude oxidative stress, FeSO4 limited it. In general, As decreased the growth and photosynthetic parameters less when in the presence of FeSO4. Furthermore, components of the antioxidant system operated in better coordination with FeSO4. Contents of non-protein thiols and phytochelatins were higher with the supply of FeSO4. Blue-Native polyacrylamide gel electrophoresis revealed an As-induced decrease in almost every multi-protein-pigment complex (MPC), and an increase in PSII subcomplex, LHCII monomers and free proteins. FeSO4 supplication helped in the retention of a better stoichiometry of light-harvesting complexes and stabilized every MPC, including supra-molecular complexes, PSI/PSII core dimer/ATP Synthase, Cytochrome b6/f dimer and LHCII dimer. FeSO4 strengthened the plant defence, perhaps by channelizing iron (Fe) and sulfur (S) to biosynthetic and anabolic pathways. Such metabolism could improve levels of antioxidant enzymes, and the contents of glutathione, and phytochelatins. Important key support might be extended to the chloroplast through better supply of Fe-S clusters. Therefore, our results suggest the importance of both iron and sulfur to combat As-induced stress in the Indian mustard plant at biochemical and molecular levels through enhanced antioxidant potential and proteomic adjustments in the photosynthetic apparatus.
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Yoshihara A, Kobayashi K. Lipids in photosynthetic protein complexes in the thylakoid membrane of plants, algae, and cyanobacteria. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2735-2750. [PMID: 35560200 DOI: 10.1093/jxb/erac017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 01/27/2022] [Indexed: 06/15/2023]
Abstract
In the thylakoid membrane of cyanobacteria and chloroplasts, many proteins involved in photosynthesis are associated with or integrated into the fluid bilayer matrix formed by four unique glycerolipid classes, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, sulfoquinovosyldiacylglycerol, and phosphatidylglycerol. Biochemical and molecular genetic studies have revealed that these glycerolipids play essential roles not only in the formation of thylakoid lipid bilayers but also in the assembly and functions of photosynthetic complexes. Moreover, considerable advances in structural biology have identified a number of lipid molecules within the photosynthetic complexes such as PSI and PSII. These data have provided important insights into the association of lipids with protein subunits in photosynthetic complexes and the distribution of lipids in the thylakoid membrane. Here, we summarize recent high-resolution observations of lipid molecules in the structures of photosynthetic complexes from plants, algae, and cyanobacteria, and evaluate the distribution of lipids among photosynthetic protein complexes and thylakoid lipid bilayers. By integrating the structural information into the findings from biochemical and molecular genetic studies, we highlight the conserved and differentiated roles of lipids in the assembly and functions of photosynthetic complexes among plants, algae, and cyanobacteria.
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Affiliation(s)
- Akiko Yoshihara
- Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, OsakaJapan
| | - Koichi Kobayashi
- Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, OsakaJapan
- Faculty of Liberal Arts and Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, OsakaJapan
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Quinone binding sites of cyt bc complexes analysed by X-ray crystallography and cryogenic electron microscopy. Biochem Soc Trans 2022; 50:877-893. [PMID: 35356963 PMCID: PMC9162462 DOI: 10.1042/bst20190963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/06/2022] [Accepted: 03/11/2022] [Indexed: 11/17/2022]
Abstract
Cytochrome (cyt) bc1, bcc and b6f complexes, collectively referred to as cyt bc complexes, are homologous isoprenoid quinol oxidising enzymes present in diverse phylogenetic lineages. Cyt bc1 and bcc complexes are constituents of the electron transport chain (ETC) of cellular respiration, and cyt b6f complex is a component of the photosynthetic ETC. Cyt bc complexes share in general the same Mitchellian Q cycle mechanism, with which they accomplish proton translocation and thus contribute to the generation of proton motive force which drives ATP synthesis. They therefore require a quinol oxidation (Qo) and a quinone reduction (Qi) site. Yet, cyt bc complexes evolved to adapt to specific electrochemical properties of different quinone species and exhibit structural diversity. This review summarises structural information on native quinones and quinone-like inhibitors bound in cyt bc complexes resolved by X-ray crystallography and cryo-EM structures. Although the Qi site architecture of cyt bc1 complex and cyt bcc complex differs considerably, quinone molecules were resolved at the respective Qi sites in very similar distance to haem bH. In contrast, more diverse positions of native quinone molecules were resolved at Qo sites, suggesting multiple quinone binding positions or captured snapshots of trajectories toward the catalytic site. A wide spectrum of inhibitors resolved at Qo or Qi site covers fungicides, antimalarial and antituberculosis medications and drug candidates. The impact of these structures for characterising the Q cycle mechanism, as well as their relevance for the development of medications and agrochemicals are discussed.
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Zhou L, Maldonado M, Padavannil A, Guo F, Letts JA. Structures of Tetrahymena's respiratory chain reveal the diversity of eukaryotic core metabolism. Science 2022; 376:831-839. [PMID: 35357889 DOI: 10.1126/science.abn7747] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Respiration is a core biological energy-converting process whose last steps are carried out by a chain of multi-subunit complexes in the inner mitochondrial membrane. To probe the functional and structural diversity of eukaryotic respiration, we examined the respiratory chain of the ciliate Tetrahymena thermophila (Tt). Using cryo-electron microscopy on a mixed sample, we solved structures of a supercomplex between Tt-complex I (CI) and Tt-CIII2 (Tt-SC I+III2) and a structure of Tt-CIV2. Tt-SC I+III2 (~2.3 MDa) is a curved assembly with structural and functional symmetry breaking. Tt-CIV2 is a ~2.7 MDa dimer with over 52 subunits per protomer, including mitochondrial carriers and a TIM83-TIM133-like domain. Our structural and functional study of the T. thermophila respiratory chain reveals divergence in key components of eukaryotic respiration, expanding our understanding of core metabolism.
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Affiliation(s)
- Long Zhou
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - María Maldonado
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Abhilash Padavannil
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Fei Guo
- BIOEM Facility, University of California, Davis, CA 95616, USA
| | - James A Letts
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
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Liu Q, Tang X, Zhang B, Li L, Zhao Y, Lv M, Li J, Kan C, Zhao Y. The effects of two sized polystyrene nanoplastics on the growth, physiological functions, and toxin production of Alexandrium tamarense. CHEMOSPHERE 2022; 291:132943. [PMID: 34793842 DOI: 10.1016/j.chemosphere.2021.132943] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/05/2021] [Accepted: 11/14/2021] [Indexed: 06/13/2023]
Abstract
Micro- and nano-plastics (MNPs) are increasingly prevalent pollutants in marine ecosystems and result in various deleterious effects on marine organisms. There have been studies evaluated the toxic effects of MNPs on marine microalgae, but few of them focused on the effects of MNPs on dinoflagellate species and their toxins production, which could have significant implications on human health and ecological safety in coastal areas. In this study, the common harmful algal blooms-causing dinoflagellate Alexandrium tamarense was exposed to 0.1 and 1 μm sized polystyrene nanoplastics (NPs) to investigate the responding patterns of population growth, multiple physiological functions, as well as the intracellular paralytic shellfish toxins (PSTs) productions. The results indicated the population growth, photosynthetic parameters, nutrients (nitrate and phosphate) uptake rates and extracellular carbonic anhydrase activities (CAext) were all inhibited by the two sized NPs, accompanied by the prolonged and more aggregated microalgal cells under the observation of scanning electron microscope (SEM), and the inhibition effects were more severe under 1 μm sized NPs than 0.1 μm sized NPs. Finally, we found the intracellular PSTs contents increased 73.59% exposed to 0.1 μm sized NPs while decreased 85.50% exposed to 1 μm sized NPs comparing the controls at 96 h, without significant changes of relative compositions. These results provided evidence that MNPs were toxic to A. tamarense and affected their intracellular PSTs productions within 96 h, which is critical to consider when evaluating the potential risks of MNPs in marine ecosystems.
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Affiliation(s)
- Qian Liu
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Xuexi Tang
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| | - Bihan Zhang
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Luying Li
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Yirong Zhao
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Mengchen Lv
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Jun Li
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Chenxiang Kan
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Yan Zhao
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.
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Chaiyarat A, Saejung C. Photosynthetic bacteria with iron oxide nanoparticles as catalyst for cooking oil removal and valuable products recovery with heavy metal co-contamination. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 140:81-89. [PMID: 35074534 DOI: 10.1016/j.wasman.2022.01.005] [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: 08/04/2021] [Revised: 10/18/2021] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
Waste cooking oil discharge causes environmental pollution in receiving waters, particularly when associated with heavy metals that can lead to formation of hazardous organometallic compounds. This study combined iron oxide nanomaterial and the anoxygenic photosynthetic bacterium Rhodopseudomonas faecalis PA2 for removal of cooking oil in the presence of heavy metals. R. faecalis PA2, with known capability to generate beneficial substances from several wastes, was capable of cooking oil removal with production of valuable products. Oil removal, biomass, protein, and carotenoid production were 82.38%, 1.48 g/L, 1,600.19 mg/L, and 1,046.33 mg/L, respectively, under optimal conditions (cooking oil as carbon source and 30% inoculum density). Iron (Fe) stimulates growth of R. faecalis; in this study, Fe3O4 nanoparticles were synthesized and used as a catalyst to facilitate interaction and high reactivity between Fe and R. faecalis PA2. Size measurement by transmission electron microscopy (17.44 nm), X-ray diffraction peaks, and magnetic susceptibility confirmed that the synthesized nanoparticles were magnetite Fe3O4. Biomass, protein, and carotenoid production of the Fe3O4 supplemented experiment increased by 61.56%, 70.78%, and 57.2%, respectively, when compared with the control. When different concentrations of heavy metals (Pb, Ni, Co, and Zn) were supplemented in the media containing cooking oil, Fe3O4 addition increased heavy metal tolerance, improved bacterial growth, and enhanced valuable products when compared with the non-supplemented group. This study reports the positive impact of nanoparticle application as a catalyst for valorization of cooking oil waste with heavy metal co-contamination by the photosynthetic bacterium R. faecalis PA2.
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Affiliation(s)
- Anuwat Chaiyarat
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Chewapat Saejung
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; Research Center for Environmental and Hazardous Substance Management (EHSM), Khon Kaen University, Khon Kaen 40002, Thailand.
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Lewis CM, Flory JD, Moore TA, Moore AL, Rittmann BE, Vermaas WFJ, Torres CI, Fromme P. Electrochemically Driven Photosynthetic Electron Transport in Cyanobacteria Lacking Photosystem II. J Am Chem Soc 2022; 144:2933-2942. [PMID: 35157427 DOI: 10.1021/jacs.1c09291] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Light-activated photosystem II (PSII) carries out the critical step of splitting water in photosynthesis. However, PSII is susceptible to light-induced damage. Here, results are presented from a novel microbial electro-photosynthetic system (MEPS) that uses redox mediators in conjunction with an electrode to drive electron transport in live Synechocystis (ΔpsbB) cells lacking PSII. MEPS-generated, light-dependent current increased with light intensity up to 2050 μmol photons m-2 s-1, which yielded a delivery rate of 113 μmol electrons h-1 mg-chl-1 and an average current density of 150 A m-2 s-1 mg-chl-1. P700+ re-reduction kinetics demonstrated that initial rates exceeded wildtype PSII-driven electron delivery. The electron delivery occurs ahead of the cytochrome b6f complex to enable both NADPH and ATP production. This work demonstrates an electrochemical system that can drive photosynthetic electron transport, provides a platform for photosynthetic foundational studies, and has the potential for improving photosynthetic performance at high light intensities.
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Affiliation(s)
- Christine M Lewis
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States.,Biodesign Institute Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States.,Biodesign Institute Swette Center for Environmental Biotechnology, Arizona State University, Tempe, Arizona 85287, United States
| | - Justin D Flory
- Biodesign Institute Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States.,Engineering Center for Negative Carbon Emmisions, at Arizona State University, Tempe, Arizona 85281, United States
| | - Thomas A Moore
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States.,Julie Ann Wrigley Global Institute of Sustainability and Innovation, Arizona State University, Tempe Arizona 85287, United States
| | - Ana L Moore
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States.,Julie Ann Wrigley Global Institute of Sustainability and Innovation, Arizona State University, Tempe Arizona 85287, United States
| | - Bruce E Rittmann
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85287, United States.,Biodesign Institute Swette Center for Environmental Biotechnology, Arizona State University, Tempe, Arizona 85287, United States
| | - Wim F J Vermaas
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - César I Torres
- Biodesign Institute Swette Center for Environmental Biotechnology, Arizona State University, Tempe, Arizona 85287, United States.,School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Petra Fromme
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States.,Biodesign Institute Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
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Manoj KM, Gideon DA, Jaeken L. Interaction of membrane-embedded cytochrome b-complexes with quinols: Classical Q-cycle and murburn model. Cell Biochem Funct 2022; 40:118-126. [PMID: 35026863 DOI: 10.1002/cbf.3682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/03/2021] [Accepted: 12/14/2021] [Indexed: 01/07/2023]
Abstract
We recently proposed a diffusible reactive (oxygen) species (DRS/DROS) based function for cytochrome b complexes (CBC) and quinones (Q)/quinols (QH2 ) in the murburn model of bioenergetics. This proposal is in direct conflict with the classical purview of Q-cycle. Via extensive analyses of the structure-function correlations of membrane-quinones/quinols and proteins, we present qualitative and quantitative arguments to infer that the classical model cannot explain the energetics, kinetics, mechanism and probabilistic considerations. Therefore, it is proposed that Q-cycle is neither necessary nor feasible at CBCs. In contrast, we substantiate that the murburn model explains: (a) crucial structural data of CBCs, (b) why quinones/quinols are utilized in bioenergetic membranes, (c) how trans-membrane potential is generated owing to effective charge separation at CBCs, (d) mobility data of O2 , DRS, Q/QH2 , and (e) utility of other reaction/membrane components. Further, the murburn model also accommodates the absence of quinones in anaerobic Archaea, wherein methanophenazines are prevalent. The work mandates that the textbooks and research agendas are refreshed to reflect the new perception. SIGNIFICANCE: The current article must be seen as a critical and detailed analysis of the role and working mechanism of quinone (Q) /quinols (QH2 ) in bioenergetic membranes. In the classical model, QH2 are perceived as highly mobile electron-transport agents that bind and donate electrons to cytochrome b complexes (CBCs), using sophisticated electronic circuitries, in order to recycle Q and pump protons. The classical perception sees radicals (such as Q*-, O2 *-, etc., also called diffusible reactive species, DRS) as wasteful or toxic (patho) physiological manifestations. It is highlighted herein that QH2 has low mobility and matrix has little protons to pump. New insights from the structural analyses of diverse CBCs and quinols, in conjunction with murburn reaction thermodynamics suggest that the electrons from substrates/quinols are effectively utilized via DRS. This perception fits into a much broader analysis of 1 and 2 electron transfers in overall redox metabolism, as recently brought out by the murburn model, wherein DRS are considered obligatory ingredients of physiology. Thus, the findings mandate a reorientation in the pertinent research field.
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Affiliation(s)
- Kelath Murali Manoj
- Biochemistry, Satyamjayatu: The Science & Ethics Foundation, Palakkad, India
| | | | - Laurent Jaeken
- Karel de Grote University College, Antwerp University Association, Campus Hoboken, Hoboken, Belgium
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Electron transfer via cytochrome b6f complex displays sensitivity to Antimycin A upon STT7 kinase activation. Biochem J 2022; 479:111-127. [PMID: 34981811 DOI: 10.1042/bcj20210802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/23/2021] [Accepted: 01/04/2022] [Indexed: 11/17/2022]
Abstract
The cytochrome b6f complex (b6f) has been initially considered as the ferredoxin-plastoquinone reductase (FQR) during cyclic electron flow (CEF) with photosystem I that is inhibited by antimycin A (AA). The binding of AA to the b6f Qi-site is aggravated by heme-ci, which challenged the FQR function of b6f during CEF. Alternative models suggest that PROTON GRADIENT REGULATION5 (PGR5) is involved in a b6f-independent, AA-sensitive FQR. Here, we show in Chlamydomonas reinhardtii that the b6f is conditionally inhibited by AA in vivo and that the inhibition did not require PGR5. Instead, activation of the STT7 kinase upon anaerobic treatment induced the AA sensitivity of b6f which was absent in stt7-1. However, a lock in State 2 due to persisting phosphorylation in the phosphatase double mutant pph1;pbcp did not increase AA sensitivity of electron transfer. The latter required a redox poise, supporting the view that state transitions and CEF are not coercively coupled. This suggests that the b6f-interacting kinase is required for structure-function modulation of the Qi-site under CEF favoring conditions. We propose that PGR5 and STT7 independently sustain AA-sensitive FQR activity of the b6f. Accordingly, PGR5-mediated electron injection into an STT7-modulated Qi-site drives a Mitchellian Q cycle in CEF conditions.
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Solymosi D, Shevela D, Allahverdiyeva Y. Nitric oxide represses photosystem II and NDH-1 in the cyanobacterium Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148507. [PMID: 34728155 DOI: 10.1016/j.bbabio.2021.148507] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 10/20/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022]
Abstract
Photosynthetic electron transfer comprises a series of light-induced redox reactions catalysed by multiprotein machinery in the thylakoid. These protein complexes possess cofactors susceptible to redox modifications by reactive small molecules. The gaseous radical nitric oxide (NO), a key signalling molecule in green algae and plants, has earlier been shown to bind to Photosystem (PS) II and obstruct electron transfer in plants. The effects of NO on cyanobacterial bioenergetics however, have long remained obscure. In this study, we exposed the model cyanobacterium Synechocystis sp. PCC 6803 to NO under anoxic conditions and followed changes in whole-cell fluorescence and oxidoreduction of P700 in vivo. Our results demonstrate that NO blocks photosynthetic electron transfer in cells by repressing PSII, PSI, and likely the NDH dehydrogenase-like complex 1 (NDH-1). We propose that iron‑sulfur clusters of NDH-1 complex may be affected by NO to such an extent that ferredoxin-derived electron injection to the plastoquinone pool, and thus cyclic electron transfer, may be inhibited. These findings reveal the profound effects of NO on Synechocystis cells and demonstrate the importance of controlled NO homeostasis in cyanobacteria.
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Affiliation(s)
- Daniel Solymosi
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI 20014, Finland
| | - Dmitry Shevela
- Chemical Biological Centre, Department of Chemistry, Umeå University, 90187 Umeå, Sweden
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI 20014, Finland.
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The Assembly of Super-Complexes in the Plant Chloroplast. Biomolecules 2021; 11:biom11121839. [PMID: 34944483 PMCID: PMC8699064 DOI: 10.3390/biom11121839] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/02/2021] [Accepted: 12/02/2021] [Indexed: 11/17/2022] Open
Abstract
Increasing evidence has revealed that the enzymes of several biological pathways assemble into larger supramolecular structures called super-complexes. Indeed, those such as association of the mitochondrial respiratory chain complexes play an essential role in respiratory activity and promote metabolic fitness. Dynamically assembled super-complexes are able to alternate between participating in large complexes and existing in a free state. However, the functional significance of the super-complexes is not entirely clear. It has been proposed that the organization of respiratory enzymes into super-complexes could reduce oxidative damage and increase metabolism efficiency. There are several protein complexes that have been revealed in the plant chloroplast, yet little research has been focused on the formation of super-complexes in this organelle. The photosystem I and light-harvesting complex I super-complex’s structure suggests that energy absorbed by light-harvesting complex I could be efficiently transferred to the PSI core by avoiding concentration quenching. Here, we will discuss in detail core complexes of photosystem I and II, the chloroplast ATPase the chloroplast electron transport chain, the Calvin–Benson cycle and a plastid localized purinosome. In addition, we will also describe the methods to identify these complexes.
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48
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Lan Y, Chen Q, Kong M, Liu Y, Lyu MJA, Perveen S, Mi H. PetM Is Essential for the Stabilization and Function of the Cytochrome b6f Complex in Arabidopsis. PLANT & CELL PHYSIOLOGY 2021; 62:1603-1614. [PMID: 34283246 DOI: 10.1093/pcp/pcab116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/16/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
The cytochrome b6f (cyt b6f) acts as a common linker of electron transport between photosystems I and II in oxygenic photosynthesis. PetM, one of eight subunits of the cyt b6f complex, is a small hydrophobic subunit at the outside periphery, the functional mechanism of which remains to be elucidated in higher plants. In this work, we found that unlike the PetM mutant in Synechocystis sp. PCC 6803, the Arabidopsis thaliana PetM mutant showed a bleached phenotype with yellowish leaves, block of photosynthetic electron transport and loss of photo-autotrophy, similar to the Arabidopsis PetC mutant. Although PetM is relatively conserved between higher plants and cyanobacteria, Synechocystis PetM could not rescue the PetM-knockout phenotype in Arabidopsis. We provide evidence that the Synechocystis PetM did not stably bind to the Arabidopsis cyt b6f complex. Based on these results, we suggest that PetM is required by Arabidopsis to maintain the function of the cyt b6f complex, likely through its close link with core subunits to form a tight 'fence' that stabilizes the core of the complex.
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Affiliation(s)
- Yixin Lan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi Chen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
| | - Mengmeng Kong
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
| | - Yanyun Liu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ming-Ju Amy Lyu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
| | - Shahnaz Perveen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
| | - Hualing Mi
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
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Sabater B. On the Edge of Dispensability, the Chloroplast ndh Genes. Int J Mol Sci 2021; 22:12505. [PMID: 34830386 PMCID: PMC8621559 DOI: 10.3390/ijms222212505] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/12/2021] [Accepted: 11/17/2021] [Indexed: 11/23/2022] Open
Abstract
The polypeptides encoded by the chloroplast ndh genes and some nuclear genes form the thylakoid NADH dehydrogenase (Ndh) complex, homologous to the mitochondrial complex I. Except for Charophyceae (algae related to higher plants) and a few Prasinophyceae, all eukaryotic algae lack ndh genes. Among vascular plants, the ndh genes are absent in epiphytic and in some species scattered among different genera, families, and orders. The recent identification of many plants lacking plastid ndh genes allows comparison on phylogenetic trees and functional investigations of the ndh genes. The ndh genes protect Angiosperms under various terrestrial stresses, maintaining efficient photosynthesis. On the edge of dispensability, ndh genes provide a test for the natural selection of photosynthesis-related genes in evolution. Variable evolutionary environments place Angiosperms without ndh genes at risk of extinction and, probably, most extant ones may have lost ndh genes recently. Therefore, they are evolutionary endpoints in phylogenetic trees. The low number of sequenced plastid DNA and the long lifespan of some Gymnosperms lacking ndh genes challenge models about the role of ndh genes protecting against stress and promoting leaf senescence. Additional DNA sequencing in Gymnosperms and investigations into the molecular mechanisms of their response to stress will provide a unified model of the evolutionary and functional consequences of the lack of ndh genes.
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Affiliation(s)
- Bartolomé Sabater
- Department of Life Sciences, University of Alcalá, Alcalá de Henares, 28805 Madrid, Spain
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Castell C, Rodríguez-Lumbreras LA, Hervás M, Fernández-Recio J, Navarro JA. New Insights into the Evolution of the Electron Transfer from Cytochrome f to Photosystem I in the Green and Red Branches of Photosynthetic Eukaryotes. PLANT & CELL PHYSIOLOGY 2021; 62:1082-1093. [PMID: 33772595 PMCID: PMC8557733 DOI: 10.1093/pcp/pcab044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/15/2021] [Indexed: 05/11/2023]
Abstract
In cyanobacteria and most green algae of the eukaryotic green lineage, the copper-protein plastocyanin (Pc) alternatively replaces the heme-protein cytochrome c6 (Cc6) as the soluble electron carrier from cytochrome f (Cf) to photosystem I (PSI). The functional and structural equivalence of 'green' Pc and Cc6 has been well established, representing an example of convergent evolution of two unrelated proteins. However, plants only produce Pc, despite having evolved from green algae. On the other hand, Cc6 is the only soluble donor available in most species of the red lineage of photosynthetic organisms, which includes, among others, red algae and diatoms. Interestingly, Pc genes have been identified in oceanic diatoms, probably acquired by horizontal gene transfer from green algae. However, the mechanisms that regulate the expression of a functional Pc in diatoms are still unclear. In the green eukaryotic lineage, the transfer of electrons from Cf to PSI has been characterized in depth. The conclusion is that in the green lineage, this process involves strong electrostatic interactions between partners, which ensure a high affinity and an efficient electron transfer (ET) at the cost of limiting the turnover of the process. In the red lineage, recent kinetic and structural modeling data suggest a different strategy, based on weaker electrostatic interactions between partners, with lower affinity and less efficient ET, but favoring instead the protein exchange and the turnover of the process. Finally, in diatoms the interaction of the acquired green-type Pc with both Cf and PSI may not yet be optimized.
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Affiliation(s)
- Carmen Castell
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, cicCartuja, Sevilla, Spain
| | - Luis A Rodríguez-Lumbreras
- Instituto de Ciencias de la Vid y del Vino (ICVV), CSIC—Universidad de La Rioja—Gobierno de La Rioja, Logroño, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, cicCartuja, Sevilla, Spain
| | - Juan Fernández-Recio
- Instituto de Ciencias de la Vid y del Vino (ICVV), CSIC—Universidad de La Rioja—Gobierno de La Rioja, Logroño, Spain
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