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Elanskaya IV, Bulychev AA, Lukashev EP, Muronets EM, Maksimov EG. Roles of ApcD and orange carotenoid protein in photoinduction of electron transport upon dark-light transition in the Synechocystis PCC 6803 mutant deficient in flavodiiron protein Flv1. PHOTOSYNTHESIS RESEARCH 2024; 159:97-114. [PMID: 37093504 DOI: 10.1007/s11120-023-01019-9] [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: 12/31/2022] [Accepted: 04/13/2023] [Indexed: 05/03/2023]
Abstract
Flavodiiron proteins Flv1/Flv3 accept electrons from photosystem (PS) I. In this work we investigated light adaptation mechanisms of Flv1-deficient mutant of Synechocystis PCC 6803, incapable to form the Flv1/Flv3 heterodimer. First seconds of dark-light transition were studied by parallel measurements of light-induced changes in chlorophyll fluorescence, P700 redox transformations, fluorescence emission at 77 K, and OCP-dependent fluorescence quenching. During the period of Calvin cycle activation upon dark-light transition, the linear electron transport (LET) in wild type is supported by the Flv1/Flv3 heterodimer, whereas in Δflv1 mutant activation of LET upon illumination is preceded by cyclic electron flow that maintains State 2. The State 2-State 1 transition and Orange Carotenoid Protein (OCP)-dependent non-photochemical quenching occur independently of each other, begin in about 10 s after the illumination of the cells and are accompanied by a short-term re-reduction of the PSI reaction center (P700+). ApcD is important for the State 2-State 1 transition in the Δflv1 mutant, but S-M rise in chlorophyll fluorescence was not completely inhibited in Δflv1/ΔapcD mutant. LET in Δflv1 mutant starts earlier than the S-M rise in chlorophyll fluorescence, and the oxidation of plastoquinol (PQH2) pool promotes the activation of PSII, transient re-reduction of P700+ and transition to State 1. An attempt to induce state transition in the wild type under high intensity light using methyl viologen, highly oxidizing P700 and PQH2, was unsuccessful, showing that oxidation of intersystem electron-transport carriers might be insufficient for the induction of State 2-State 1 transition in wild type of Synechocystis under high light.
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Affiliation(s)
- Irina V Elanskaya
- Department of Genetics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Alexander A Bulychev
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Evgeny P Lukashev
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Elena M Muronets
- Department of Genetics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Eugene G Maksimov
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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2
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Kisgeropoulos E, Bharadwaj VS, Ledinina A, Lubner CE, Mulder DW, Smolinski SL, Boehm M, Gutekunst K, King PW, Svedruzic D. Structural and biophysical properties of a [4Fe4S] ferredoxin-like protein from Synechocystis sp. PCC 6803 with a unique two domain structure. J Inorg Biochem 2024; 251:112428. [PMID: 38008043 DOI: 10.1016/j.jinorgbio.2023.112428] [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: 09/06/2023] [Revised: 10/23/2023] [Accepted: 11/11/2023] [Indexed: 11/28/2023]
Abstract
Electron carrier proteins (ECPs), binding iron-sulfur clusters, are vital components within the intricate network of metabolic and photosynthetic reactions. They play a crucial role in the distribution of reducing equivalents. In Synechocystis sp. PCC 6803, the ECP network includes at least nine ferredoxins. Previous research, including global expression analyses and protein binding studies, has offered initial insights into the functional roles of individual ferredoxins within this network. This study primarily focuses on Ferredoxin 9 (slr2059). Through sequence analysis and computational modeling, Ferredoxin 9 emerges as a unique ECP with a distinctive two-domain architecture. It consists of a C-terminal iron‑sulfur binding domain and an N-terminal domain with homology to Nil-domain proteins, connected by a structurally rigid 4-amino acid linker. Notably, in contrast to canonical [2Fe2S] ferredoxins exemplified by PetF (ssl0020), which feature highly acidic surfaces facilitating electron transfer with photosystem I reaction centers, models of Ferredoxin 9 reveal a more neutral to basic protein surface. Using a combination of electron paramagnetic resonance spectroscopy and square-wave voltammetry on heterologously produced Ferredoxin 9, this study demonstrates that the protein coordinates 2×[4Fe4S]2+/1+ redox-active and magnetically interacting clusters, with measured redox potentials of -420 ± 9 mV and - 516 ± 10 mV vs SHE. A more in-depth analysis of Fdx9's unique structure and protein sequence suggests that this type of Nil-2[4Fe4S] multi-domain ferredoxin is well conserved in cyanobacteria, bearing structural similarities to proteins involved in homocysteine synthesis in methanogens.
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Affiliation(s)
- Effie Kisgeropoulos
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Vivek S Bharadwaj
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Anastasia Ledinina
- Department of Molecular and Structural Biochemistry, North Carolina State University, USA
| | - Carolyn E Lubner
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Sharon L Smolinski
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Marko Boehm
- Department of Biology, Botanical Institute, Christian-Albrechts-University, Kiel, Germany; Department of Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Kirstin Gutekunst
- Department of Biology, Botanical Institute, Christian-Albrechts-University, Kiel, Germany; Department of Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Drazenka Svedruzic
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
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3
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Santos-Merino M, Sakkos JK, Singh AK, Ducat DC. Coordination of carbon partitioning and photosynthesis by a two-component signaling network in Synechococcus elongatus PCC 7942. Metab Eng 2024; 81:38-52. [PMID: 37925065 DOI: 10.1016/j.ymben.2023.11.001] [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: 06/09/2023] [Revised: 10/26/2023] [Accepted: 11/02/2023] [Indexed: 11/06/2023]
Abstract
Photosynthetic organisms need to balance the rate of photosynthesis with the utilization of photosynthetic products by downstream reactions. While such "source/sink" pathways are well-interrogated in plants, analogous regulatory systems are unknown or poorly studied in single-celled algal and cyanobacterial species. Towards the identification of energy/sugar sensors in cyanobacteria, we utilized an engineered strain of Synechococcus elongatus PCC 7942 that allows experimental manipulation of carbon status. We conducted a screening of all two-component systems (TCS) and serine/threonine kinases (STKs) encoded in S. elongatus PCC 7942 by analyzing phenotypes consistent with sucrose-induced relaxation of sink inhibition. We narrowed the candidate sensor proteins by analyzing changes observed after sucrose feeding. We show that a clustered TCS network containing RpaA, CikB, ManS and NblS are involved in the regulation of genes related to photosynthesis, pigment synthesis, and Rubisco concentration in response to sucrose. Altogether, these results highlight a regulatory TCS group that may play under-appreciated functions in carbon partitioning and energy balancing in cyanobacteria.
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Affiliation(s)
- María Santos-Merino
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, United States
| | - Jonathan K Sakkos
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, United States
| | - Amit K Singh
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, United States
| | - Daniel C Ducat
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, United States; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States.
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4
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Shimakawa G. Electron transport in cyanobacterial thylakoid membranes: Are cyanobacteria simple models for photosynthetic organisms? JOURNAL OF EXPERIMENTAL BOTANY 2023:erad118. [PMID: 37025010 DOI: 10.1093/jxb/erad118] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Indexed: 06/19/2023]
Abstract
Cyanobacteria are structurally the simplest oxygenic phototrophs, which makes it difficult to understand the regulation of photosynthesis because the photosynthetic and respiratory processes share the same thylakoid membranes and cytosolic space. This review aimed to summarise the molecular mechanisms and in vivo activities of electron transport in cyanobacterial thylakoid membranes based on the latest progress in photosynthesis research in cyanobacteria. Photosynthetic linear electron transport for CO2 assimilation has the dominant electron flux in the thylakoid membranes. The capacity of O2 photoreduction in cyanobacteria is comparable to the photosynthetic CO2 assimilation, which is mediated by flavodiiron proteins. Additionally, cyanobacterial thylakoid membranes harbour the significant electron flux of respiratory electron transport through a homologue of respiratory complex I, which is also recognized as the part of cyclic electron transport chain if it is coupled with photosystem I in the light. Further, O2-independent alternative electron transports through hydrogenase and nitrate reductase function with reduced ferredoxin as the electron donor. Whereas all these electron transports are recently being understood one by one, the complexity as the whole regulatory system remains to be uncovered in near future.
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Affiliation(s)
- Ginga Shimakawa
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan
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5
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Mellor SB, Behrendorff JBYH, Ipsen JØ, Crocoll C, Laursen T, Gillam EMJ, Pribil M. Exploiting photosynthesis-driven P450 activity to produce indican in tobacco chloroplasts. FRONTIERS IN PLANT SCIENCE 2023; 13:1049177. [PMID: 36743583 PMCID: PMC9890960 DOI: 10.3389/fpls.2022.1049177] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 12/14/2022] [Indexed: 05/28/2023]
Abstract
Photosynthetic organelles offer attractive features for engineering small molecule bioproduction by their ability to convert solar energy into chemical energy required for metabolism. The possibility to couple biochemical production directly to photosynthetic assimilation as a source of energy and substrates has intrigued metabolic engineers. Specifically, the chemical diversity found in plants often relies on cytochrome P450-mediated hydroxylations that depend on reductant supply for catalysis and which often lead to metabolic bottlenecks for heterologous production of complex molecules. By directing P450 enzymes to plant chloroplasts one can elegantly deal with such redox prerequisites. In this study, we explore the capacity of the plant photosynthetic machinery to drive P450-dependent formation of the indigo precursor indoxyl-β-D-glucoside (indican) by targeting an engineered indican biosynthetic pathway to tobacco (Nicotiana benthamiana) chloroplasts. We show that both native and engineered variants belonging to the human CYP2 family are catalytically active in chloroplasts when driven by photosynthetic reducing power and optimize construct designs to improve productivity. However, while increasing supply of tryptophan leads to an increase in indole accumulation, it does not improve indican productivity, suggesting that P450 activity limits overall productivity. Co-expression of different redox partners also does not improve productivity, indicating that supply of reducing power is not a bottleneck. Finally, in vitro kinetic measurements showed that the different redox partners were efficiently reduced by photosystem I but plant ferredoxin provided the highest light-dependent P450 activity. This study demonstrates the inherent ability of photosynthesis to support P450-dependent metabolic pathways. Plants and photosynthetic microbes are therefore uniquely suited for engineering P450-dependent metabolic pathways regardless of enzyme origin. Our findings have implications for metabolic engineering in photosynthetic hosts for production of high-value chemicals or drug metabolites for pharmacological studies.
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Affiliation(s)
- Silas B. Mellor
- Section for Plant Biochemistry, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - James B. Y. H. Behrendorff
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Research Council (ARC) Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, QLD, Australia
| | - Johan Ø. Ipsen
- Section for Forest, Nature and Biomass, Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
| | - Christoph Crocoll
- DynaMo Center, Section for Molecular Plant Biology, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - Tomas Laursen
- Section for Plant Biochemistry, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - Elizabeth M. J. Gillam
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Mathias Pribil
- Section for Molecular Plant Biology, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
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6
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Ibrahim IM, Rowden SJL, Cramer WA, Howe CJ, Puthiyaveetil S. Thiol redox switches regulate the oligomeric state of cyanobacterial Rre1, RpaA, and RpaB response regulators. FEBS Lett 2022; 596:1533-1543. [PMID: 35353903 PMCID: PMC9321951 DOI: 10.1002/1873-3468.14340] [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: 02/18/2022] [Revised: 03/11/2022] [Accepted: 03/16/2022] [Indexed: 11/18/2022]
Abstract
Cyanobacteria employ two‐component sensor‐response regulator systems to monitor and respond to environmental challenges. The response regulators RpaA, RpaB, Rre1 and RppA are integral to circadian clock function and abiotic stress acclimation in cyanobacteria. RpaA, RpaB and Rre1 are known to interact with ferredoxin or thioredoxin, raising the possibility of their thiol regulation. Here, we report that Synechocystis sp. PCC 6803 Rre1, RpaA and RpaB exist as higher‐order oligomers under oxidising conditions and that reduced thioredoxin A converts them to monomers. We further show that these response regulators contain redox‐responsive cysteine residues with an Em7 around −300 mV. These findings suggest a direct thiol modulation of the activity of these response regulators, independent of their cognate sensor kinases.
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Affiliation(s)
- Iskander M Ibrahim
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Stephen J L Rowden
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - William A Cramer
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Christopher J Howe
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Sujith Puthiyaveetil
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
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7
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Shimakawa G, Shoguchi E, Burlacot A, Ifuku K, Che Y, Kumazawa M, Tanaka K, Nakanishi S. Coral symbionts evolved a functional polycistronic flavodiiron gene. PHOTOSYNTHESIS RESEARCH 2022; 151:113-124. [PMID: 34309771 DOI: 10.1007/s11120-021-00867-7] [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: 04/12/2021] [Accepted: 07/17/2021] [Indexed: 05/26/2023]
Abstract
Photosynthesis in cyanobacteria, green algae, and basal land plants is protected against excess reducing pressure on the photosynthetic chain by flavodiiron proteins (FLV) that dissipate photosynthetic electrons by reducing O2. In these organisms, the genes encoding FLV are always conserved in the form of a pair of two-type isozymes (FLVA and FLVB) that are believed to function in O2 photo-reduction as a heterodimer. While coral symbionts (dinoflagellates of the family Symbiodiniaceae) are the only algae to harbor FLV in photosynthetic red plastid lineage, only one gene is found in transcriptomes and its role and activity remain unknown. Here, we characterized the FLV genes in Symbiodiniaceae and found that its coding region is composed of tandemly repeated FLV sequences. By measuring the O2-dependent electron flow and P700 oxidation, we suggest that this atypical FLV is active in vivo. Based on the amino-acid sequence alignment and the phylogenetic analysis, we conclude that in coral symbionts, the gene pair for FLVA and FLVB have been fused to construct one coding region for a hybrid enzyme, which presumably occurred when or after both genes were inherited from basal green algae to the dinoflagellate. Immunodetection suggested the FLV polypeptide to be cleaved by a post-translational mechanism, adding it to the rare cases of polycistronic genes in eukaryotes. Our results demonstrate that FLV are active in coral symbionts with genomic arrangement that is unique to these species. The implication of these unique features on their symbiotic living environment is discussed.
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Affiliation(s)
- Ginga Shimakawa
- Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan.
| | - Eiichi Shoguchi
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Adrien Burlacot
- Aix Marseille University, CEA, CNRS, Institut de Biosciences Et Biotechnologies Aix-Marseille, CEA Cadarache, 13108, Saint Paul-Lez-Durance, France
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, 111 Koshland Hall, Berkeley, CA, 94720-3102, USA
| | - Kentaro Ifuku
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Yufen Che
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Minoru Kumazawa
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Kenya Tanaka
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8631, Japan
| | - Shuji Nakanishi
- Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8631, Japan
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8
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Nikkanen L, Solymosi D, Jokel M, Allahverdiyeva Y. Regulatory electron transport pathways of photosynthesis in cyanobacteria and microalgae: Recent advances and biotechnological prospects. PHYSIOLOGIA PLANTARUM 2021; 173:514-525. [PMID: 33764547 DOI: 10.1111/ppl.13404] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Cyanobacteria and microalgae perform oxygenic photosynthesis where light energy is harnessed to split water into oxygen and protons. This process releases electrons that are used by the photosynthetic electron transport chain to form reducing equivalents that provide energy for the cell metabolism. Constant changes in environmental conditions, such as light availability, temperature, and access to nutrients, create the need to balance the photochemical reactions and the metabolic demands of the cell. Thus, cyanobacteria and microalgae evolved several auxiliary electron transport (AET) pathways to disperse the potentially harmful over-supply of absorbed energy. AET pathways are comprised of electron sinks, e.g. flavodiiron proteins (FDPs) or other terminal oxidases, and pathways that recycle electrons around photosystem I, like NADPH-dehydrogenase-like complexes (NDH) or the ferredoxin-plastoquinone reductase (FQR). Under controlled conditions the need for these AET pathways is decreased and AET can even be energetically wasteful. Therefore, redirecting photosynthetic reducing equivalents to biotechnologically useful reactions, catalyzed by i.e. innate hydrogenases or heterologous enzymes, offers novel possibilities to apply photosynthesis research.
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Affiliation(s)
- Lauri Nikkanen
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Daniel Solymosi
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Martina Jokel
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
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Hasegawa H, Tsurumaki T, Imamura S, Sonoike K, Tanaka K. The circadian rhythm regulator RpaA modulates photosynthetic electron transport and alters the preferable temperature range for growth in a cyanobacterium. FEBS Lett 2021; 595:1480-1492. [PMID: 33728661 DOI: 10.1002/1873-3468.14075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 11/07/2022]
Abstract
Cyanobacterial strains can grow within a specific temperature range that approximately corresponds to their natural habitat. However, how the preferable temperature range for growth (PTRG) is determined at the molecular level remains unclear. In this study, we detected a PTRG upshift in a mutant strain of Synechococcus elongatus PCC 7942 lacking the circadian rhythm regulator RpaA. Subsequent analyses revealed that RpaA decreases the electron transport from photosystem I to NADPH. The change in electron transport likely inhibits H2 O2 generation under high-temperature conditions and contributes to the observed PTRG upshift in rpaA-deficient cells. The importance of the effects of the circadian rhythm regulator on the PTRG is discussed.
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Affiliation(s)
- Hazuki Hasegawa
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Tatsuhiro Tsurumaki
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Kintake Sonoike
- Faculty of Education and Integrated Arts and Sciences, Waseda University, Tokyo, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
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10
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Genetic, Genomics, and Responses to Stresses in Cyanobacteria: Biotechnological Implications. Genes (Basel) 2021; 12:genes12040500. [PMID: 33805386 PMCID: PMC8066212 DOI: 10.3390/genes12040500] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Cyanobacteria are widely-diverse, environmentally crucial photosynthetic prokaryotes of great interests for basic and applied science. Work to date has focused mostly on the three non-nitrogen fixing unicellular species Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002, which have been selected for their genetic and physiological interests summarized in this review. Extensive "omics" data sets have been generated, and genome-scale models (GSM) have been developed for the rational engineering of these cyanobacteria for biotechnological purposes. We presently discuss what should be done to improve our understanding of the genotype-phenotype relationships of these models and generate robust and predictive models of their metabolism. Furthermore, we also emphasize that because Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002 represent only a limited part of the wide biodiversity of cyanobacteria, other species distantly related to these three models, should be studied. Finally, we highlight the need to strengthen the communication between academic researchers, who know well cyanobacteria and can engineer them for biotechnological purposes, but have a limited access to large photobioreactors, and industrial partners who attempt to use natural or engineered cyanobacteria to produce interesting chemicals at reasonable costs, but may lack knowledge on cyanobacterial physiology and metabolism.
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11
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Jodlbauer J, Rohr T, Spadiut O, Mihovilovic MD, Rudroff F. Biocatalysis in Green and Blue: Cyanobacteria. Trends Biotechnol 2021; 39:875-889. [PMID: 33468423 DOI: 10.1016/j.tibtech.2020.12.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 12/17/2022]
Abstract
Recently, several studies have proven the potential of cyanobacteria as whole-cell biocatalysts for biotransformation. Compared to heterotrophic hosts, cyanobacteria show unique advantages thanks to their photoautotrophic metabolism. Their ability to use light as energy and CO2 as carbon source promises a truly sustainable production platform. Their photoautotrophic metabolism offers an encouraging source of reducing power, which makes them attractive for redox-based biotechnological purposes. To exploit the full potential of these whole-cell biocatalysts, cyanobacterial cells must be considered in their entirety. With this emphasis, this review summarizes the latest developments in cyanobacteria research with a strong focus on the benefits associated with their unique metabolism. Remaining bottlenecks and recent strategies to overcome them are evaluated for their potential in future applications.
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Affiliation(s)
- Julia Jodlbauer
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/OC-163, 1060 Vienna, Austria
| | - Thomas Rohr
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/OC-163, 1060 Vienna, Austria
| | - Oliver Spadiut
- Institute of Chemical Engineering, research area Biochemical Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria
| | - Marko D Mihovilovic
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/OC-163, 1060 Vienna, Austria
| | - Florian Rudroff
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/OC-163, 1060 Vienna, Austria.
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12
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Nikkanen L, Santana Sánchez A, Ermakova M, Rögner M, Cournac L, Allahverdiyeva Y. Functional redundancy between flavodiiron proteins and NDH-1 in Synechocystis sp. PCC 6803. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1460-1476. [PMID: 32394539 DOI: 10.1111/tpj.14812] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 05/09/2023]
Abstract
In oxygenic photosynthetic organisms, excluding angiosperms, flavodiiron proteins (FDPs) catalyze light-dependent reduction of O2 to H2 O. This alleviates electron pressure on the photosynthetic apparatus and protects it from photodamage. In Synechocystis sp. PCC 6803, four FDP isoforms function as hetero-oligomers of Flv1 and Flv3 and/or Flv2 and Flv4. An alternative electron transport pathway mediated by the NAD(P)H dehydrogenase-like complex (NDH-1) also contributes to redox hemostasis and the photoprotection of photosynthesis. Four NDH-1 types have been characterized in cyanobacteria: NDH-11 and NDH-12 , which function in respiration; and NDH-13 and NDH-14 , which function in CO2 uptake. All four types are involved in cyclic electron transport. Along with single FDP mutants (∆flv1 and Δflv3) and the double NDH-1 mutants (∆d1d2, which is deficient in NDH-11,2 and ∆d3d4, which is deficient in NDH-13,4 ), we studied triple mutants lacking one of Flv1 or Flv3, and NDH-11,2 or NDH-13,4 . We show that the presence of either Flv1/3 or NDH-11,2 , but not NDH-13,4 , is indispensable for survival during changes in growth conditions from high CO2 /moderate light to low CO2 /high light. Our results show functional redundancy between FDPs and NDH-11,2 under the studied conditions. We suggest that ferredoxin probably functions as a primary electron donor to both Flv1/3 and NDH-11,2 , allowing their functions to be dynamically coordinated for efficient oxidation of photosystem I and for photoprotection under variable CO2 and light availability.
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Affiliation(s)
- Lauri Nikkanen
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Anita Santana Sánchez
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Maria Ermakova
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Matthias Rögner
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr-University Bochum, Bochum, Germany
| | - Laurent Cournac
- Eco&Sols, University of Montpellier, IRD, CIRAD, INRAE, Institut Agro, Montpellier, France
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
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13
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Identification of the electron donor to flavodiiron proteins in Synechocystis sp. PCC 6803 by in vivo spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148256. [PMID: 32622739 DOI: 10.1016/j.bbabio.2020.148256] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/19/2020] [Accepted: 06/19/2020] [Indexed: 01/18/2023]
Abstract
Flavodiiron proteins (FDPs) of photosynthetic organisms play a photoprotective role by reducing oxygen to water and thus avoiding the accumulation of excess electrons on the photosystem I (PSI) acceptor side under stress conditions. In Synechocystis sp. PCC 6803 grown under high CO2, both FDPs Flv1 and Flv3 are indispensable for oxygen reduction. We performed a detailed in vivo kinetic study of wild-type (WT) and Δflv1/3 strains of Synechocystis using light-induced NADPH fluorescence and near-infrared absorption of iron-sulfur clusters from ferredoxin and the PSI acceptors (FAFB), collectively named FeS. These measurements were performed under conditions where the Calvin-Benson cycle is inactive or poorly activated. Under such conditions, the NADPH decay following a short illumination decays in parallel in both strains and exhibits a time lag which is correlated to the presence of reduced FeS. On the contrary, reduced FeS decays much faster in WT than in Δflv1/3 (13 vs 2 s-1). These data unambiguously show that reduced ferredoxin, or possibly reduced FAFB, is the direct electron donor to the Flv1/Flv3 heterodimer. Evidences for large reduction of (FAFB) and recombination reactions within PSI were also provided by near-infrared absorption. Mutants lacking either the NDH1-L complex, the homolog of complex I of respiration, or the Pgr5 protein show no difference with WT in the oxidation of reduced FeS following a short illumination. These observations question the participation of a significant cyclic electron flow in cyanobacteria during the first seconds of the induction phase of photosynthesis.
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Jiang Y, Liu Y, Zhang J. Antibiotics induced alterations in cell density, photosynthesis, microcystin synthesis and proteomic expression of Microcystis aeruginosa during CuSO 4 treatment. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 222:105473. [PMID: 32203795 DOI: 10.1016/j.aquatox.2020.105473] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 03/14/2020] [Accepted: 03/15/2020] [Indexed: 06/10/2023]
Abstract
Antibiotic contaminants have the potential to interfere with the control of cyanobacterial bloom through generating hormesis in cyanobacteria at current contamination level of ng L-1. This study investigated the influence of a mixture of four frequently detected antibiotics, amoxicillin, ciprofloxacin, sulfamethoxazole and tetracycline, during the treatment of Microcystis aeruginosa by copper sulfate (CuSO4) algaecide. CuSO4 significantly (p < 0.05) inhibited cell density, growth rate, Fv/Fm value, chlorophyll a content and microcystin production ability of M. aeruginosa in a dose-dependent manner at application doses of 0.01-0.05 mg L-1. Besides, CuSO4 inhibited oxidation-reduction process, photosynthesis and biosynthesis in M. aeruginosa at the proteomic level. Preventative application of CuSO4 to a low density (4 × 105 cells mL-1) of M. aeruginosa effectively prevented the formation of bloom at low CuSO4 doses, which is a possible route for eliminating the negative effects of CuSO4 algaecide in aquatic environments. The presence of mixed antibiotics alleviated the toxicity of CuSO4 in M. aeruginosa, through the downregulation of cation transport proteins and the upregulation of proteins related with chlorophyll a synthesis, photosynthesis, gene expression and oxidation-reduction. Mixed antibiotics also promoted microcystin synthesis in CuSO4 treated cells through the upregulation of microcystin synthetases. Mixed antibiotics significantly (p < 0.05) increased cell density, growth rate, Fv/Fm value, chlorophyll a content and microcystin production ability in CuSO4 treated cells at test concentrations of 80 and 200 ng L-1. A no-impact threshold of 20 ng L-1 for mixed antibiotics (5 ng L-1 for each antibiotic) was suggested for eliminating the interference of antibiotic contaminants on cyanobacterial bloom control.
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Affiliation(s)
- Yunhan Jiang
- School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, PR China
| | - Ying Liu
- School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, PR China.
| | - Jian Zhang
- School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, PR China
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15
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Mellor SB, Vinde MH, Nielsen AZ, Hanke GT, Abdiaziz K, Roessler MM, Burow M, Motawia MS, Møller BL, Jensen PE. Defining optimal electron transfer partners for light-driven cytochrome P450 reactions. Metab Eng 2019; 55:33-43. [PMID: 31091467 DOI: 10.1016/j.ymben.2019.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/02/2019] [Accepted: 05/04/2019] [Indexed: 12/16/2022]
Abstract
Plants and cyanobacteria are promising heterologous hosts for metabolic engineering, and particularly suited for expression of cytochrome P450 (P450s), enzymes that catalyse key steps in biosynthetic pathways leading to valuable natural products such as alkaloids, terpenoids and phenylpropanoids. P450s are often difficult to express and require a membrane-bound NADPH-dependent reductase, complicating their use in metabolic engineering and bio-production. We previously demonstrated targeting of heterologous P450s to thylakoid membranes both in N. benthamiana chloroplasts and cyanobacteria, and functional substitution of their native reductases with the photosynthetic apparatus via the endogenous soluble electron carrier ferredoxin. However, because ferredoxin acts as a sorting hub for photosynthetic reducing power, there is fierce competition for reducing equivalents, which limits photosynthesis-driven P450 output. This study compares the ability of four electron carriers to increase photosynthesis-driven P450 activity. These carriers, three plant ferredoxins and a flavodoxin-like engineered protein derived from cytochrome P450 reductase, show only modest differences in their electron transfer to our model P450, CYP79A1 in vitro. However, only the flavodoxin-like carrier supplies appreciable reducing power in the presence of competition for reduced ferredoxin, because it possesses a redox potential that renders delivery of reducing equivalents to endogenous processes inefficient. We further investigate the efficacy of these electron carrier proteins in vivo by expressing them transiently in N. benthamiana fused to CYP79A1. All but one of the fusion enzymes show improved sequestration of photosynthetic reducing power. Fusion with the flavodoxin-like carrier offers the greatest improvement in this comparison - nearly 25-fold on a per protein basis. Thus, this study demonstrates that synthetic electron transfer pathways with optimal redox potentials can alleviate the problem of endogenous competition for reduced ferredoxin and sets out a new metabolic engineering strategy useful for producing valuable natural products.
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Affiliation(s)
- Silas Busck Mellor
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Marcos Hamborg Vinde
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Agnieszka Zygadlo Nielsen
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Guy Thomas Hanke
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| | - Kaltum Abdiaziz
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| | - Maxie M Roessler
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| | - Meike Burow
- DyNaMo Center of Excellence, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Mohammed Saddik Motawia
- Villum Research Center for Plant Plasticity, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Birger Lindberg Møller
- Villum Research Center for Plant Plasticity, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Poul Erik Jensen
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
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16
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Santana-Sanchez A, Solymosi D, Mustila H, Bersanini L, Aro EM, Allahverdiyeva Y. Flavodiiron proteins 1-to-4 function in versatile combinations in O 2 photoreduction in cyanobacteria. eLife 2019; 8:e45766. [PMID: 31294693 PMCID: PMC6658166 DOI: 10.7554/elife.45766] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 07/10/2019] [Indexed: 12/15/2022] Open
Abstract
Flavodiiron proteins (FDPs) constitute a group of modular enzymes widespread in Bacteria, Archaea and Eukarya. Synechocystis sp. PCC 6803 has four FDPs (Flv1-4), which are essential for the photoprotection of photosynthesis. A direct comparison of light-induced O2 reduction (Mehler-like reaction) under high (3% CO2, HC) and low (air level CO2, LC) inorganic carbon conditions demonstrated that the Flv1/Flv3 heterodimer is solely responsible for an efficient steady-state O2 photoreduction under HC, with flv2 and flv4 expression strongly down-regulated. Conversely, under LC conditions, Flv1/Flv3 acts only as a transient electron sink, due to the competing withdrawal of electrons by the highly induced NDH-1 complex. Further, in vivo evidence is provided indicating that Flv2/Flv4 contributes to the Mehler-like reaction when naturally expressed under LC conditions, or, when artificially overexpressed under HC. The O2 photoreduction driven by Flv2/Flv4 occurs down-stream of PSI in a coordinated manner with Flv1/Flv3 and supports slow and steady-state O2 photoreduction.
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Affiliation(s)
| | - Daniel Solymosi
- Molecular Plant Biology, Department of BiochemistryUniversity of TurkuTurkuFinland
| | - Henna Mustila
- Molecular Plant Biology, Department of BiochemistryUniversity of TurkuTurkuFinland
| | - Luca Bersanini
- Molecular Plant Biology, Department of BiochemistryUniversity of TurkuTurkuFinland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of BiochemistryUniversity of TurkuTurkuFinland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of BiochemistryUniversity of TurkuTurkuFinland
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17
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Jokel M, Nagy V, Tóth SZ, Kosourov S, Allahverdiyeva Y. Elimination of the flavodiiron electron sink facilitates long-term H 2 photoproduction in green algae. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:280. [PMID: 31827608 PMCID: PMC6894204 DOI: 10.1186/s13068-019-1618-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/23/2019] [Indexed: 05/14/2023]
Abstract
BACKGROUND The development of renewable and sustainable biofuels to cover the future energy demand is one of the most challenging issues of our time. Biohydrogen, produced by photosynthetic microorganisms, has the potential to become a green biofuel and energy carrier for the future sustainable world, since it provides energy without CO2 emission. The recent development of two alternative protocols to induce hydrogen photoproduction in green algae enables the function of the O2-sensitive [FeFe]-hydrogenases, located at the acceptor side of photosystem I, to produce H2 for several days. These protocols prevent carbon fixation and redirect electrons toward H2 production. In the present work, we employed these protocols to a knockout Chlamydomonas reinhardtii mutant lacking flavodiiron proteins (FDPs), thus removing another possible electron competitor with H2 production. RESULTS The deletion of the FDP electron sink resulted in the enhancement of H2 photoproduction relative to wild-type C. reinhardtii. Additionally, the lack of FDPs leads to a more effective obstruction of carbon fixation even under elongated light pulses. CONCLUSIONS We demonstrated that the rather simple adjustment of cultivation conditions together with genetic manipulation of alternative electron pathways of photosynthesis results in efficient re-routing of electrons toward H2 photoproduction. Furthermore, the introduction of a short recovery phase by regular switching from H2 photoproduction to biomass accumulation phase allows to maintain cell fitness and use photosynthetic cells as long-term H2-producing biocatalysts.
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Affiliation(s)
- Martina Jokel
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Valéria Nagy
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Szilvia Z. Tóth
- Institute of Plant Biology, Biological Research Centre, Szeged, Temesvári krt. 62, Szeged, 6726 Hungary
| | - Sergey Kosourov
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
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18
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Shimakawa G, Miyake C. Oxidation of P700 Ensures Robust Photosynthesis. FRONTIERS IN PLANT SCIENCE 2018; 9:1617. [PMID: 30459798 PMCID: PMC6232666 DOI: 10.3389/fpls.2018.01617] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/18/2018] [Indexed: 05/18/2023]
Abstract
In the light, photosynthetic cells can potentially suffer from oxidative damage derived from reactive oxygen species. Nevertheless, a variety of oxygenic photoautotrophs, including cyanobacteria, algae, and plants, manage their photosynthetic systems successfully. In the present article, we review previous research on how these photoautotrophs safely utilize light energy for photosynthesis without photo-oxidative damage to photosystem I (PSI). The reaction center chlorophyll of PSI, P700, is kept in an oxidized state in response to excess light, under high light and low CO2 conditions, to tune the light utilization and dissipate the excess photo-excitation energy in PSI. Oxidation of P700 is co-operatively regulated by a number of molecular mechanisms on both the electron donor and acceptor sides of PSI. The strategies to keep P700 oxidized are diverse among a variety of photoautotrophs, which are evolutionarily optimized for their ecological niche.
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Affiliation(s)
- Ginga Shimakawa
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Chikahiro Miyake
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
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19
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Guan X, Chen S, Voon CP, Wong KB, Tikkanen M, Lim BL. FdC1 and Leaf-Type Ferredoxins Channel Electrons From Photosystem I to Different Downstream Electron Acceptors. FRONTIERS IN PLANT SCIENCE 2018; 9:410. [PMID: 29670639 PMCID: PMC5893904 DOI: 10.3389/fpls.2018.00410] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/14/2018] [Indexed: 05/24/2023]
Abstract
Plant-type ferredoxins in Arabidopsis transfer electrons from the photosystem I to multiple redox-driven enzymes involved in the assimilation of carbon, nitrogen, and sulfur. Leaf-type ferredoxins also modulate the switch between the linear and cyclic electron routes of the photosystems. Recently, two novel ferredoxin homologs with extra C-termini were identified in the Arabidopsis genome (AtFdC1, AT4G14890; AtFdC2, AT1G32550). FdC1 was considered as an alternative electron acceptor of PSI under extreme ferredoxin-deficient conditions. Here, we showed that FdC1 could interact with some, but not all, electron acceptors of leaf-type Fds, including the ferredoxin-thioredoxin reductase (FTR), sulfite reductase (SiR), and nitrite reductase (NiR). Photoreduction assay on cytochrome c and enzyme assays confirmed its capability to receive electrons from PSI and donate electrons to the Fd-dependent SiR and NiR but not to the ferredoxin-NADP+ oxidoreductase (FNR). Hence, FdC1 and leaf-type Fds may play differential roles by channeling electrons from photosystem I to different downstream electron acceptors in photosynthetic tissues. In addition, the median redox potential of FdC1 may allow it to receive electrons from FNR in non-photosynthetic plastids.
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Affiliation(s)
- Xiaoqian Guan
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Shuai Chen
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Chia Pao Voon
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Kam-Bo Wong
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Mikko Tikkanen
- Department of Biochemistry and Food Chemistry, Molecular Plant Biology, University of Turku, Turku, Finland
| | - Boon L. Lim
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong
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20
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Przybyla-Toscano J, Roland M, Gaymard F, Couturier J, Rouhier N. Roles and maturation of iron-sulfur proteins in plastids. J Biol Inorg Chem 2018; 23:545-566. [PMID: 29349662 PMCID: PMC6006212 DOI: 10.1007/s00775-018-1532-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 12/14/2017] [Indexed: 12/28/2022]
Abstract
One reason why iron is an essential element for most organisms is its presence in prosthetic groups such as hemes or iron–sulfur (Fe–S) clusters, which are notably required for electron transfer reactions. As an organelle with an intense metabolism in plants, chloroplast relies on many Fe–S proteins. This includes those present in the electron transfer chain which will be, in fact, essential for most other metabolic processes occurring in chloroplasts, e.g., carbon fixation, nitrogen and sulfur assimilation, pigment, amino acid, and vitamin biosynthetic pathways to cite only a few examples. The maturation of these Fe–S proteins requires a complex and specific machinery named SUF (sulfur mobilisation). The assembly process can be split in two major steps, (1) the de novo assembly on scaffold proteins which requires ATP, iron and sulfur atoms, electrons, and thus the concerted action of several proteins forming early acting assembly complexes, and (2) the transfer of the preformed Fe–S cluster to client proteins using a set of late-acting maturation factors. Similar machineries, having in common these basic principles, are present in the cytosol and in mitochondria. This review focuses on the currently known molecular details concerning the assembly and roles of Fe–S proteins in plastids.
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Affiliation(s)
- Jonathan Przybyla-Toscano
- Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, 54500, Vandoeuvre-lès-Nancy, France
| | - Mélanie Roland
- Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, 54500, Vandoeuvre-lès-Nancy, France
| | - Frédéric Gaymard
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/Université Montpellier 2, SupAgro Campus, 34060, Montpellier, France
| | - Jérémy Couturier
- Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, 54500, Vandoeuvre-lès-Nancy, France
| | - Nicolas Rouhier
- Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, 54500, Vandoeuvre-lès-Nancy, France.
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21
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Mellor SB, Vavitsas K, Nielsen AZ, Jensen PE. Photosynthetic fuel for heterologous enzymes: the role of electron carrier proteins. PHOTOSYNTHESIS RESEARCH 2017; 134:329-342. [PMID: 28285375 DOI: 10.1007/s11120-017-0364-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 02/27/2017] [Indexed: 05/21/2023]
Abstract
Plants, cyanobacteria, and algae generate a surplus of redox power through photosynthesis, which makes them attractive for biotechnological exploitations. While central metabolism consumes most of the energy, pathways introduced through metabolic engineering can also tap into this source of reducing power. Recent work on the metabolic engineering of photosynthetic organisms has shown that the electron carriers such as ferredoxin and flavodoxin can be used to couple heterologous enzymes to photosynthetic reducing power. Because these proteins have a plethora of interaction partners and rely on electrostatically steered complex formation, they form productive electron transfer complexes with non-native enzymes. A handful of examples demonstrate channeling of photosynthetic electrons to drive the activity of heterologous enzymes, and these focus mainly on hydrogenases and cytochrome P450s. However, competition from native pathways and inefficient electron transfer rates present major obstacles, which limit the productivity of heterologous reactions coupled to photosynthesis. We discuss specific approaches to address these bottlenecks and ensure high productivity of such enzymes in a photosynthetic context.
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Affiliation(s)
- Silas Busck Mellor
- Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Konstantinos Vavitsas
- Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Agnieszka Zygadlo Nielsen
- Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Poul Erik Jensen
- Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
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22
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Kizawa A, Kawahara A, Takashima K, Takimura Y, Nishiyama Y, Hihara Y. The LexA transcription factor regulates fatty acid biosynthetic genes in the cyanobacterium Synechocystis sp. PCC 6803. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:189-198. [PMID: 28744961 DOI: 10.1111/tpj.13644] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 06/22/2017] [Accepted: 07/18/2017] [Indexed: 05/12/2023]
Abstract
Specific transcription factors have been identified in various heterotrophic bacterial species that regulate the sets of genes required for fatty acid metabolism. Here, we report that expression of the fab genes, encoding fatty acid biosynthetic enzymes, is regulated by the global regulator LexA in the photoautotrophic cyanobacterium Synechocystis sp. PCC 6803. Sll1626, an ortholog of the well-known LexA repressor involved in the SOS response in heterotrophic bacteria, was isolated from crude extracts of Synechocystis by DNA affinity chromatography, reflecting its binding to the upstream region of the acpP-fabF and fabI genes. An electrophoresis mobility shift assay revealed that the recombinant LexA protein can bind to the upstream region of each fab gene tested (fabD, fabH, fabF, fabG, fabZ and fabI). Quantitative RT-PCR analysis of the wild type and a lexA-disrupted mutant strain suggested that LexA acts as a repressor of the fab genes involved in initiation of fatty acid biosynthesis (fabD, fabH and fabF) and the first reductive step in the subsequent elongation cycle (fabG) under normal growth conditions. Under nitrogen-depleted conditions, downregulation of fab gene expression is partly achieved through an increase in LexA-repressing activity. In contrast, under phosphate-depleted conditions, fab gene expression is upregulated, probably due to the loss of repression by LexA. We further demonstrate that elimination of LexA largely increases the production of fatty acids in strains modified to secrete free fatty acids.
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Affiliation(s)
- Ayumi Kizawa
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570, Japan
| | - Akihito Kawahara
- Biological Science Research, KAO Corporation, Wakayama, 640-8580, Japan
| | - Kosuke Takashima
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570, Japan
| | - Yasushi Takimura
- Biological Science Research, KAO Corporation, Wakayama, 640-8580, Japan
| | - Yoshitaka Nishiyama
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570, Japan
| | - Yukako Hihara
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570, Japan
- Core Research of Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
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23
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Shi M, Zhang X, Pei G, Chen L, Zhang W. Functional Diversity of Transcriptional Regulators in the Cyanobacterium Synechocystis sp. PCC 6803. Front Microbiol 2017; 8:280. [PMID: 28270809 PMCID: PMC5318462 DOI: 10.3389/fmicb.2017.00280] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 02/09/2017] [Indexed: 11/16/2022] Open
Abstract
Functions of transcriptional regulators (TRs) are still poorly understood in the model cyanobacterium Synechocystis sp. PCC 6803. To address the issue, we constructed knockout mutants for 32 putative TR-encoding genes of Synechocystis, and comparatively analyzed their phenotypes under autotrophic growth condition and metabolic profiles using liquid chromatography-mass spectrometry-based metabolomics. The results showed that only four mutants of TR genes, sll1872 (lytR), slr0741 (phoU), slr0395 (ntcB), and slr1871 (pirR), showed differential growth patterns in BG11 medium when compared with the wild type; however, in spite of no growth difference observed for the remaining TR mutants, metabolomic profiling showed that they were different at the metabolite level, suggesting significant functional diversity of TRs in Synechocystis. In addition, an integrative metabolomic and gene families’ analysis of all TR mutants led to the identification of five pairs of TR genes that each shared close relationship in both gene families and metabolomic clustering trees, suggesting possible conserved functions of these TRs during evolution. Moreover, more than a dozen pairs of TR genes with different origin and evolution were found with similar metabolomic profiles, suggesting a possible functional convergence of the TRs during genome evolution. Finally, a protein–protein network analysis was performed to predict regulatory targets of TRs, allowing inference of possible regulatory gene targets for 4 out of five pairs of TRs. This study provided new insights into the regulatory functions and evolution of TR genes in Synechocystis.
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Affiliation(s)
- Mengliang Shi
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Key Laboratory of Systems Bioengineering - Ministry of Education, Tianjin UniversityTianjin, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and EngineeringTianjin, China
| | - Xiaoqing Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Key Laboratory of Systems Bioengineering - Ministry of Education, Tianjin UniversityTianjin, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and EngineeringTianjin, China
| | - Guangsheng Pei
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Key Laboratory of Systems Bioengineering - Ministry of Education, Tianjin UniversityTianjin, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and EngineeringTianjin, China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Key Laboratory of Systems Bioengineering - Ministry of Education, Tianjin UniversityTianjin, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and EngineeringTianjin, China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Key Laboratory of Systems Bioengineering - Ministry of Education, Tianjin UniversityTianjin, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and EngineeringTianjin, China; Center for Biosafety Research and Strategy, Tianjin UniversityTianjin, China
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The drug ornidazole inhibits photosynthesis in a different mechanism described for protozoa and anaerobic bacteria. Biochem J 2016; 473:4413-4426. [DOI: 10.1042/bcj20160433] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 09/01/2016] [Accepted: 09/19/2016] [Indexed: 11/17/2022]
Abstract
Ornidazole of the 5-nitroimidazole drug family is used to treat protozoan and anaerobic bacterial infections via a mechanism that involves preactivation by reduction of the nitro group, and production of toxic derivatives and radicals. Metronidazole, another drug family member, has been suggested to affect photosynthesis by draining electrons from the electron carrier ferredoxin, thus inhibiting NADP+ reduction and stimulating radical and peroxide production. Here we show, however, that ornidazole inhibits photosynthesis via a different mechanism. While having a minute effect on the photosynthetic electron transport and oxygen photoreduction, ornidazole hinders the activity of two Calvin cycle enzymes, triose-phosphate isomerase (TPI) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Modeling of ornidazole's interaction with ferredoxin of the protozoan Trichomonas suggests efficient electron tunneling from the iron–sulfur cluster to the nitro group of the drug. A similar docking site of ornidazole at the plant-type ferredoxin does not exist, and the best simulated alternative does not support such efficient tunneling. Notably, TPI was inhibited by ornidazole in the dark or when electron transport was blocked by dichloromethyl diphenylurea, indicating that this inhibition was unrelated to the electron transport machinery. Although TPI and GAPDH isoenzymes are involved in glycolysis and gluconeogenesis, ornidazole's effect on respiration of photoautotrophs is moderate, thus raising its value as an efficient inhibitor of photosynthesis. The scarcity of Calvin cycle inhibitors capable of penetrating cell membranes emphasizes on the value of ornidazole for studying the regulation of this cycle.
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Kinoshita M, Kim JY, Kume S, Sakakibara Y, Sugiki T, Kojima C, Kurisu G, Ikegami T, Hase T, Kimata-Ariga Y, Lee YH. Physicochemical nature of interfaces controlling ferredoxin NADP(+) reductase activity through its interprotein interactions with ferredoxin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1200-11. [PMID: 26087388 DOI: 10.1016/j.bbabio.2015.05.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/27/2015] [Accepted: 05/29/2015] [Indexed: 01/27/2023]
Abstract
Although acidic residues of ferredoxin (Fd) are known to be essential for activities of various Fd-dependent enzymes, including ferredoxin NADP(+) reductase (FNR) and sulfite reductase (SiR), through electrostatic interactions with basic residues of partner enzymes, non-electrostatic contributions such as hydrophobic forces remain largely unknown. We herein demonstrated that intermolecular hydrophobic and charge-charge interactions between Fd and enzymes were both critical for enzymatic activity. Systematic site-directed mutagenesis, which altered physicochemical properties of residues on the interfaces of Fd for FNR /SiR, revealed various changes in activities of both enzymes. The replacement of serine 43 of Fd to a hydrophobic residue (S43W) and charged residue (S43D) increased and decreased FNR activity, respectively, while S43W showed significantly lower SiR activity without affecting SiR activity by S43D, suggesting that hydrophobic and electrostatic interprotein forces affected FNR activity. Enzyme kinetics revealed that changes in FNR activity by mutating Fd correlated with Km, but not with kcat or activation energy, indicating that interprotein interactions determined FNR activity. Calorimetry-based binding thermodynamics between Fd and FNR showed different binding modes of FNR to wild-type, S43W, or S43D, which were controlled by enthalpy and entropy, as shown by the driving force plot. Residue-based NMR spectroscopy of (15)N FNR with Fds also revealed distinct binding modes of each complex based on different directions of NMR peak shifts with similar overall chemical shift differences. We proposed that subtle adjustments in both hydrophobic and electrostatic forces were critical for enzymatic activity, and these results may be applicable to protein-based electron transfer systems.
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Affiliation(s)
- Misaki Kinoshita
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Ju Yaen Kim
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Satoshi Kume
- Cellular Function Imaging Team, Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, Kobe, Hyogo 650-0047, Japan
| | - Yukiko Sakakibara
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Toshihiko Sugiki
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Chojiro Kojima
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Takahisa Ikegami
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Toshiharu Hase
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Yoko Kimata-Ariga
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Young-Ho Lee
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
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26
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Zhang C. Involvement of Iron-Containing Proteins in Genome Integrity in Arabidopsis Thaliana. Genome Integr 2015; 6:2. [PMID: 27330736 PMCID: PMC4911903 DOI: 10.4103/2041-9414.155953] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 03/12/2015] [Indexed: 01/03/2023] Open
Abstract
The Arabidopsis genome encodes numerous iron-containing proteins such as iron-sulfur (Fe-S) cluster proteins and hemoproteins. These proteins generally utilize iron as a cofactor, and they perform critical roles in photosynthesis, genome stability, electron transfer, and oxidation-reduction reactions. Plants have evolved sophisticated mechanisms to maintain iron homeostasis for the assembly of functional iron-containing proteins, thereby ensuring genome stability, cell development, and plant growth. Over the past few years, our understanding of iron-containing proteins and their functions involved in genome stability has expanded enormously. In this review, I provide the current perspectives on iron homeostasis in Arabidopsis, followed by a summary of iron-containing protein functions involved in genome stability maintenance and a discussion of their possible molecular mechanisms.
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Affiliation(s)
- Caiguo Zhang
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado, Aurora, Colorado, USA
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27
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Lehtimäki N, Koskela MM, Dahlström KM, Pakula E, Lintala M, Scholz M, Hippler M, Hanke GT, Rokka A, Battchikova N, Salminen TA, Mulo P. Posttranslational modifications of FERREDOXIN-NADP+ OXIDOREDUCTASE in Arabidopsis chloroplasts. PLANT PHYSIOLOGY 2014; 166:1764-76. [PMID: 25301888 PMCID: PMC4256869 DOI: 10.1104/pp.114.249094] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Rapid responses of chloroplast metabolism and adjustments to photosynthetic machinery are of utmost importance for plants' survival in a fluctuating environment. These changes may be achieved through posttranslational modifications of proteins, which are known to affect the activity, interactions, and localization of proteins. Recent studies have accumulated evidence about the crucial role of a multitude of modifications, including acetylation, methylation, and glycosylation, in the regulation of chloroplast proteins. Both of the Arabidopsis (Arabidopsis thaliana) leaf-type FERREDOXIN-NADP(+) OXIDOREDUCTASE (FNR) isoforms, the key enzymes linking the light reactions of photosynthesis to carbon assimilation, exist as two distinct forms with different isoelectric points. We show that both AtFNR isoforms contain multiple alternative amino termini and undergo light-responsive addition of an acetyl group to the α-amino group of the amino-terminal amino acid of proteins, which causes the change in isoelectric point. Both isoforms were also found to contain acetylation of a conserved lysine residue near the active site, while no evidence for in vivo phosphorylation or glycosylation was detected. The dynamic, multilayer regulation of AtFNR exemplifies the complex regulatory network systems controlling chloroplast proteins by a range of posttranslational modifications, which continues to emerge as a novel area within photosynthesis research.
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Affiliation(s)
- Nina Lehtimäki
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Minna M Koskela
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Käthe M Dahlström
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Eveliina Pakula
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Minna Lintala
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Martin Scholz
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Michael Hippler
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Guy T Hanke
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Anne Rokka
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Natalia Battchikova
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Tiina A Salminen
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Paula Mulo
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
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Mustila H, Allahverdiyeva Y, Isojärvi J, Aro EM, Eisenhut M. The bacterial-type [4Fe-4S] ferredoxin 7 has a regulatory function under photooxidative stress conditions in the cyanobacterium Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1293-304. [PMID: 24780314 DOI: 10.1016/j.bbabio.2014.04.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 04/10/2014] [Accepted: 04/13/2014] [Indexed: 12/15/2022]
Abstract
Ferredoxins function as electron carrier in a wide range of metabolic and regulatory reactions. It is not clear yet, whether the multiplicity of ferredoxin proteins is also reflected in functional multiplicity in photosynthetic organisms. We addressed the biological function of the bacterial-type ferredoxin, Fed7 in the cyanobacterium Synechocystis sp. PCC 6803. The expression of fed7 is induced under low CO₂ conditions and further enhanced by additional high light treatment. These conditions are considered as promoting photooxidative stress, and prompted us to investigate the biological function of Fed7 under these conditions. Loss of Fed7 did not inhibit growth of the mutant strain Δfed7 but significantly modulated photosynthesis parameters when the mutant was grown under low CO₂ and high light conditions. Characteristics of the Δfed7 mutant included elevated chlorophyll and photosystem I levels as well as reduced abundance and activity of photosystem II. Transcriptional profiling of the mutant under low CO₂ conditions demonstrated changes in gene regulation of the carbon concentrating mechanism and photoprotective mechanisms such as the Flv2/4 electron valve, the PSII dimer stabilizing protein Sll0218, and chlorophyll biosynthesis. We conclude that the function of Fed7 is connected to coping with photooxidative stress, possibly by constituting a redox-responsive regulatory element in photoprotection. In photosynthetic eukaryotes domains homologous to Fed7 are exclusively found in chloroplast DnaJ-like proteins that are likely involved in remodeling of regulator protein complexes. It is conceivable that the regulatory function of Fed7 evolved in cyanobacteria and was recruited by Viridiplantae as the controller for the chloroplast DnaJ-like proteins.
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Affiliation(s)
- H Mustila
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland.
| | - Y Allahverdiyeva
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland.
| | - J Isojärvi
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland.
| | - E M Aro
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland.
| | - M Eisenhut
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland.
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29
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Peden EA, Boehm M, Mulder DW, Davis R, Old WM, King PW, Ghirardi ML, Dubini A. Identification of global ferredoxin interaction networks in Chlamydomonas reinhardtii. J Biol Chem 2013; 288:35192-209. [PMID: 24100040 DOI: 10.1074/jbc.m113.483727] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ferredoxins (FDXs) can distribute electrons originating from photosynthetic water oxidation, fermentation, and other reductant-generating pathways to specific redox enzymes in different organisms. The six FDXs identified in Chlamydomonas reinhardtii are not fully characterized in terms of their biological function. In this report, we present data from the following: (a) yeast two-hybrid screens, identifying interaction partners for each Chlamydomonas FDX; (b) pairwise yeast two-hybrid assays measuring FDX interactions with proteins from selected biochemical pathways; (c) affinity pulldown assays that, in some cases, confirm and even expand the interaction network for FDX1 and FDX2; and (d) in vitro NADP(+) reduction and H2 photo-production assays mediated by each FDX that verify their role in these two pathways. Our results demonstrate new potential roles for FDX1 in redox metabolism and carbohydrate and fatty acid biosynthesis, for FDX2 in anaerobic metabolism, and possibly in state transition. Our data also suggest that FDX3 is involved in nitrogen assimilation, FDX4 in glycolysis and response to reactive oxygen species, and FDX5 in hydrogenase maturation. Finally, we provide experimental evidence that FDX1 serves as the primary electron donor to two important biological pathways, NADPH and H2 photo-production, whereas FDX2 is capable of driving these reactions at less than half the rate observed for FDX1.
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Affiliation(s)
- Erin A Peden
- From the National Renewable Energy Laboratory, Golden, Colorado 80401 and
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30
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Summerfield TC, Crawford TS, Young RD, Chua JPS, Macdonald RL, Sherman LA, Eaton-Rye JJ. Environmental pH affects photoautotrophic growth of Synechocystis sp. PCC 6803 strains carrying mutations in the lumenal proteins of PSII. PLANT & CELL PHYSIOLOGY 2013; 54:859-74. [PMID: 23444302 DOI: 10.1093/pcp/pct036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Synechocystis sp. strain PCC 6803 grows photoautotrophically across a broad pH range, but wild-type cultures reach a higher density at elevated pH; however, photoheterotrophic growth is similar at high and neutral pH. A number of PSII mutants each lacking at least one lumenal extrinsic protein, and carrying a second PSII lumenal mutation, are able to grow photoautotrophically in BG-11 medium at pH 10.0, but not pH 7.5. We investigated the basis of this pH effect and observed no pH-specific change in variable fluorescence yield from PSII centers of the wild type or the pH-dependent ΔPsbO:ΔPsbU and ΔPsbV:ΔCyanoQ strains; however, 77 K fluorescence emission spectra indicated increased coupling of the phycobilisome (PBS) antenna at pH 10.0 in all mutants. DNA microarray data showed a cell-wide response to transfer from pH 10.0 to pH 7.5, including decreased mRNA levels of a number of oxidative stress-responsive transcripts. We hypothesize that this transcriptional response led to increased tolerance against reactive oxygen species and in particular singlet oxygen. This response enabled photoautotrophic growth of the PSII mutants at pH 10.0. This hypothesis was supported by increased resistance of all strains to rose bengal at pH 10.0 compared with pH 7.5.
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Affiliation(s)
- Tina C Summerfield
- Department of Botany, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
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31
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Lücker S, Nowka B, Rattei T, Spieck E, Daims H. The Genome of Nitrospina gracilis Illuminates the Metabolism and Evolution of the Major Marine Nitrite Oxidizer. Front Microbiol 2013; 4:27. [PMID: 23439773 PMCID: PMC3578206 DOI: 10.3389/fmicb.2013.00027] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 02/02/2013] [Indexed: 01/17/2023] Open
Abstract
In marine systems, nitrate is the major reservoir of inorganic fixed nitrogen. The only known biological nitrate-forming reaction is nitrite oxidation, but despite its importance, our knowledge of the organisms catalyzing this key process in the marine N-cycle is very limited. The most frequently encountered marine NOB are related to Nitrospina gracilis, an aerobic chemolithoautotrophic bacterium isolated from ocean surface waters. To date, limited physiological and genomic data for this organism were available and its phylogenetic affiliation was uncertain. In this study, the draft genome sequence of N. gracilis strain 3/211 was obtained. Unexpectedly for an aerobic organism, N. gracilis lacks classical reactive oxygen defense mechanisms and uses the reductive tricarboxylic acid cycle for carbon fixation. These features indicate microaerophilic ancestry and are consistent with the presence of Nitrospina in marine oxygen minimum zones. Fixed carbon is stored intracellularly as glycogen, but genes for utilizing external organic carbon sources were not identified. N. gracilis also contains a full gene set for oxidative phosphorylation with oxygen as terminal electron acceptor and for reverse electron transport from nitrite to NADH. A novel variation of complex I may catalyze the required reverse electron flow to low-potential ferredoxin. Interestingly, comparative genomics indicated a strong evolutionary link between Nitrospina, the nitrite-oxidizing genus Nitrospira, and anaerobic ammonium oxidizers, apparently including the horizontal transfer of a periplasmically oriented nitrite oxidoreductase and other key genes for nitrite oxidation at an early evolutionary stage. Further, detailed phylogenetic analyses using concatenated marker genes provided evidence that Nitrospina forms a novel bacterial phylum, for which we propose the name Nitrospinae.
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Affiliation(s)
- Sebastian Lücker
- Department of Microbial Ecology, Ecology Centre, University of Vienna Vienna, Austria
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Mella-Flores D, Six C, Ratin M, Partensky F, Boutte C, Le Corguillé G, Marie D, Blot N, Gourvil P, Kolowrat C, Garczarek L. Prochlorococcus and Synechococcus have Evolved Different Adaptive Mechanisms to Cope with Light and UV Stress. Front Microbiol 2012; 3:285. [PMID: 23024637 PMCID: PMC3441193 DOI: 10.3389/fmicb.2012.00285] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 07/19/2012] [Indexed: 11/13/2022] Open
Abstract
Prochlorococcus and Synechococcus, which numerically dominate vast oceanic areas, are the two most abundant oxygenic phototrophs on Earth. Although they require solar energy for photosynthesis, excess light and associated high UV radiations can induce high levels of oxidative stress that may have deleterious effects on their growth and productivity. Here, we compared the photophysiologies of the model strains Prochlorococcus marinus PCC 9511 and Synechococcus sp. WH7803 grown under a bell-shaped light/dark cycle of high visible light supplemented or not with UV. Prochlorococcus exhibited a higher sensitivity to photoinactivation than Synechococcus under both conditions, as shown by a larger drop of photosystem II (PSII) quantum yield at noon and different diel patterns of the D1 protein pool. In the presence of UV, the PSII repair rate was significantly depressed at noon in Prochlorococcus compared to Synechococcus. Additionally, Prochlorococcus was more sensitive than Synechococcus to oxidative stress, as shown by the different degrees of PSII photoinactivation after addition of hydrogen peroxide. A transcriptional analysis also revealed dramatic discrepancies between the two organisms in the diel expression patterns of several genes involved notably in the biosynthesis and/or repair of photosystems, light-harvesting complexes, CO(2) fixation as well as protection mechanisms against light, UV, and oxidative stress, which likely translate profound differences in their light-controlled regulation. Altogether our results suggest that while Synechococcus has developed efficient ways to cope with light and UV stress, Prochlorococcus cells seemingly survive stressful hours of the day by launching a minimal set of protection mechanisms and by temporarily bringing down several key metabolic processes. This study provides unprecedented insights into understanding the distinct depth distributions and dynamics of these two picocyanobacteria in the field.
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Affiliation(s)
- Daniella Mella-Flores
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
- Departamento de Ecología, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de ChileSantiago, Chile
| | - Christophe Six
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
| | - Morgane Ratin
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
| | - Frédéric Partensky
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
| | - Christophe Boutte
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
| | - Gildas Le Corguillé
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- CNRS, FR 2424, Service Informatique et GénomiqueRoscoff, France
| | - Dominique Marie
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
| | - Nicolas Blot
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
- Laboratoire Microorganismes: Génome et Environnement, Clermont Université, Université Blaise PascalClermont-Ferrand, France
- Laboratoire Microorganismes: Génome et Environnement, CNRS, UMR 6023Aubière, France
| | - Priscillia Gourvil
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
| | - Christian Kolowrat
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
- Center for Doctoral Studies, University of ViennaVienna, Austria
| | - Laurence Garczarek
- Station Biologique, UPMC-Université Paris VIRoscoff, France
- Groupe Plancton Océanique, CNRS, UMR 7144Roscoff, France
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Lodeyro AF, Ceccoli RD, Pierella Karlusich JJ, Carrillo N. The importance of flavodoxin for environmental stress tolerance in photosynthetic microorganisms and transgenic plants. Mechanism, evolution and biotechnological potential. FEBS Lett 2012; 586:2917-24. [PMID: 22819831 DOI: 10.1016/j.febslet.2012.07.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 07/06/2012] [Accepted: 07/09/2012] [Indexed: 10/28/2022]
Abstract
Ferredoxins are electron shuttles harboring iron-sulfur clusters which participate in oxido-reductive pathways in organisms displaying very different lifestyles. Ferredoxin levels decline in plants and cyanobacteria exposed to environmental stress and iron starvation. Flavodoxin is an isofunctional flavoprotein present in cyanobacteria and algae (not plants) which is induced and replaces ferredoxin under stress. Expression of a chloroplast-targeted flavodoxin in plants confers tolerance to multiple stresses and iron deficit. We discuss herein the bases for functional equivalence between the two proteins, the reasons for ferredoxin conservation despite its susceptibility to aerobic stress and for the loss of flavodoxin as an adaptive trait in higher eukaryotes. We also propose a mechanism to explain the tolerance conferred by flavodoxin when expressed in plants.
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Affiliation(s)
- Anabella F Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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Moal G, Lagoutte B. Photo-induced electron transfer from photosystem I to NADP(+): characterization and tentative simulation of the in vivo environment. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1635-45. [PMID: 22683536 DOI: 10.1016/j.bbabio.2012.05.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 05/28/2012] [Accepted: 05/30/2012] [Indexed: 12/01/2022]
Abstract
The photoproduction of NADPH in photosynthetic organisms requires the successive or concomitant interaction of at least three proteins: photosystem I (PSI), ferredoxin (Fd) and ferredoxin:NADP(+) oxidoreductase (FNR). These proteins and their surrounding medium have been carefully analysed in the cyanobacterium Synechocystis sp. PCC 6803. A high value of 550mg/ml was determined for the overall solute content of the cell soluble compartment. PSI and Fd are present at similar concentrations, around 500μM, whereas the FNR associated to phycobilisome is about 4 fold less concentrated. Membrane densities of FNR and trimeric PSI have been estimated to 2000 and 2550 per μm(2), respectively. An artificial confinement of Fd to PSI was designed using fused constructs between Fd and PsaE, a peripheral and stroma located PSI subunit. The best covalent system in terms of photocatalysed NADPH synthesis can be equivalent to the free system in a dilute medium. In a macrosolute crowded medium (375mg/ml), this optimized PSI/Fd covalent complex exhibited a huge superiority compared to the free system. This is a likely consequence of restrained diffusion constraints due to the vicinity of two out of the three protein partners. In vivo, Fd is the free partner, but the constant proximity between PSI and the phycobilisome associated FNR creates a similar situation, with two closely associated partners. This organization seems well adapted for an efficient in vivo production of the stable and fast diffusing NADPH.
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Affiliation(s)
- Gwenaëlle Moal
- Service de Bioenergetique, Biologie Structurale et Mecanismes, Gif sur Yvette, France
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Zhao S, Xie P, Li G, Jun C, Cai Y, Xiong Q, Zhao Y. The proteomic study on cellular responses of the testes of zebrafish (Danio rerio
) exposed to microcystin-RR. Proteomics 2012; 12:300-12. [DOI: 10.1002/pmic.201100214] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Novel insights into the regulation of LexA in the cyanobacterium Synechocystis sp. Strain PCC 6803. J Bacteriol 2011; 193:3804-14. [PMID: 21642463 DOI: 10.1128/jb.00289-11] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The transcription factor LexA in the cyanobacterium Synechocystis sp. strain PCC 6803 has been shown to regulate genes that are not directly involved in DNA repair but instead in several different metabolic pathways. However, the signal transduction pathways remain largely uncharacterized. The present work gives novel insights into the regulation of LexA in this unicellular cyanobacterium. A combination of Northern and Western blotting, using specific antibodies against the cyanobacterial LexA, was employed to show that this transcription regulator is under posttranscriptional control, in addition to the classical and already-described transcriptional regulation. Moreover, detailed two-dimensional (2D) electrophoresis analyses of the protein revealed that LexA undergoes posttranslational modifications. Finally, a fully segregated LexA::GFP (green fluorescent protein) fusion-modified strain was produced to image LexA's spatial distribution in live cells. The fusion protein retains DNA binding capabilities, and the GFP fluorescence indicates that LexA is localized in the innermost region of the cytoplasm, decorating the DNA in an evenly distributed pattern. The implications of these findings for the overall role of LexA in Synechocystis sp. strain PCC 6803 are further discussed.
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