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Piazza F, Parisse P, Passerino J, Marsich E, Bersanini L, Porrelli D, Baj G, Donati I, Sacco P. Controlled Quenching of Agarose Defines Hydrogels with Tunable Structural, Bulk Mechanical, Surface Nanomechanical, and Cell Response in 2D Cultures. Adv Healthc Mater 2023; 12:e2300973. [PMID: 37369130 DOI: 10.1002/adhm.202300973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/12/2023] [Indexed: 06/29/2023]
Abstract
The scaffolding of agarose hydrogel networks depends critically on the rate of cooling (quenching) after heating. Efforts are made to understand the kinetics and evolution of biopolymer self-assembly upon cooling, but information is lacking on whether quenching might affect the final hydrogel structure and performance. Here, a material strategy for the fine modulation of quenching that involves temperature-curing steps of agarose is reported. Combining microscopy techniques, standard and advanced macro/nanomechanical tools, it is revealed that agarose accumulates on the surface when the curing temperature is set at 121 °C. The inhomogeneity can be mostly recovered when it is reduced to 42 °C. This has a drastic effect on the stiffness of the surface, but not on the viscoelasticity, roughness, and wettability. When hydrogels are strained at small/large deformations, the curing temperature has no effect on the viscoelastic response of the hydrogel bulk but does play a role in the onset of the non-linear region. Cells cultured on these hydrogels exhibit surface stiffness-sensing that affects cell adhesion, spreading, F-actin fiber tension, and assembly of vinculin-rich focal adhesions. Collectively, the results indicate that the temperature curing of agarose is an efficient strategy to produce networks with tunable mechanics and is suitable for mechanobiology studies.
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Affiliation(s)
- Francesco Piazza
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri 5, Trieste, I-34127, Italy
| | - Pietro Parisse
- NanoInnovation Lab, Elettra-Sincrotrone Trieste S.C.p.A., Trieste, I-34149, Italy
- Istituto Officina dei Materiali (IOM-CNR), Area Science Park, Trieste, I-34149, Italy
| | - Julia Passerino
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri 5, Trieste, I-34127, Italy
| | - Eleonora Marsich
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Piazza dell'Ospitale 1, Trieste, I-34129, Italy
| | - Luca Bersanini
- Optics11 Life, Hettenheuvelweg 37-39, Amsterdam, 1101 BM, The Netherlands
| | - Davide Porrelli
- Interdepartmental Centre for Advanced Microscopy, Department of Life Sciences, University of Trieste, Via Alexander Fleming 31/A, Trieste, I-34127, Italy
| | - Gabriele Baj
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri 5, Trieste, I-34127, Italy
| | - Ivan Donati
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri 5, Trieste, I-34127, Italy
| | - Pasquale Sacco
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri 5, Trieste, I-34127, Italy
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Mascoli V, Bersanini L, Croce R. Far-red absorption and light-use efficiency trade-offs in chlorophyll f photosynthesis. Nat Plants 2020; 6:1044-1053. [PMID: 32661277 DOI: 10.1038/s41477-020-0718-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 06/04/2020] [Indexed: 05/28/2023]
Abstract
Plants and cyanobacteria use the chlorophylls embedded in their photosystems to absorb photons and perform charge separation, the first step of converting solar energy to chemical energy. While oxygenic photosynthesis is primarily based on chlorophyll a photochemistry, which is powered by red light, a few cyanobacterial species can harness less energetic photons when growing in far-red light. Acclimatization to far-red light involves the incorporation of a small number of molecules of red-shifted chlorophyll f in the photosystems, whereas the most abundant pigment remains chlorophyll a. Due to its different energetics, chlorophyll f is expected to alter the excited-state dynamics of the photosynthetic units and, ultimately, their performances. Here we combined time-resolved fluorescence measurements on intact cells and isolated complexes to show that chlorophyll f insertion slows down the overall energy trapping in both photosystems. While this marginally affects the efficiency of photosystem I, it substantially decreases that of photosystem II. Nevertheless, we show that despite the lower energy output, the insertion of red-shifted chlorophylls in the photosystems remains advantageous in environments that are enriched in far-red light and therefore represents a viable strategy for extending the photosynthetically active spectrum in other organisms, including plants. However, careful design of the new photosynthetic units will be required to preserve their efficiency.
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Affiliation(s)
- Vincenzo Mascoli
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Luca Bersanini
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Bersanini L, Allahverdiyeva Y, Battchikova N, Heinz S, Lespinasse M, Ruohisto E, Mustila H, Nickelsen J, Vass I, Aro EM. Dissecting the Photoprotective Mechanism Encoded by the flv4-2 Operon: a Distinct Contribution of Sll0218 in Photosystem II Stabilization. Plant Cell Environ 2017; 40:378-389. [PMID: 27928824 DOI: 10.1111/pce.12872] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/17/2016] [Accepted: 11/20/2016] [Indexed: 06/06/2023]
Abstract
In Synechocystis sp. PCC 6803, the flv4-2 operon encodes the flavodiiron proteins Flv2 and Flv4 together with a small protein, Sll0218, providing photoprotection for Photosystem II (PSII). Here, the distinct roles of Flv2/Flv4 and Sll0218 were addressed, using a number of flv4-2 operon mutants. In the ∆sll0218 mutant, the presence of Flv2/Flv4 rescued PSII functionality as compared with ∆sll0218-flv2, where neither Sll0218 nor the Flv2/Flv4 heterodimer are expressed. Nevertheless, both the ∆sll0218 and ∆sll0218-flv2 mutants demonstrated deficiency in accumulation of PSII proteins suggesting a role for Sll0218 in PSII stabilization, which was further supported by photoinhibition experiments. Moreover, the accumulation of PSII assembly intermediates occurred in Sll0218-lacking mutants. The YFP-tagged Sll0218 protein localized in a few spots per cell at the external side of the thylakoid membrane, and biochemical membrane fractionation revealed clear enrichment of Sll0218 in the PratA-defined membranes, where the early biogenesis steps of PSII occur. Further, the characteristic antenna uncoupling feature of the ∆flv4-2 operon mutants is shown to be related to PSII destabilization in the absence of Sll0218. It is concluded that the Flv2/Flv4 heterodimer supports PSII functionality, while the Sll0218 protein assists PSII assembly and stabilization, including optimization of light harvesting.
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Affiliation(s)
- Luca Bersanini
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Yagut Allahverdiyeva
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Natalia Battchikova
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Steffen Heinz
- Molecular Plant Sciences, Ludwig-Maximillians-Universität München, Biozentrum, Grosshaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Maija Lespinasse
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Essi Ruohisto
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Henna Mustila
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Jörg Nickelsen
- Molecular Plant Sciences, Ludwig-Maximillians-Universität München, Biozentrum, Grosshaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Imre Vass
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, P.O. Box 521, H-6701, Szeged, Hungary
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
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Pagliano C, Bersanini L, Cella R, Longoni P, Pantaleoni L, Dass A, Leelavathi S, Reddy VS. Use of Nicotiana tabacum transplastomic plants engineered to express a His-tagged CP47 for the isolation of functional photosystem II core complexes. Plant Physiol Biochem 2017; 111:266-273. [PMID: 27987471 DOI: 10.1016/j.plaphy.2016.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/04/2016] [Accepted: 12/04/2016] [Indexed: 06/06/2023]
Abstract
This work focuses on the development of a molecular tool for purification of Photosystem II (PSII) from Nicotiana tabacum (L.). To this end, the chloroplast psbB gene encoding the CP47 PSII subunit was replaced with an engineered version of the same gene containing a C-terminal His-tag. Molecular analyses assessed the effective integration of the recombinant gene and its expression. Despite not exhibiting any obvious phenotype, the transplastomic plants remained heteroplasmic even after three rounds of regeneration under antibiotic selection. However, the recombinant His-tagged CP47 protein associated in vivo to the other PSII subunits allowing the isolation of a functional PSII core complex, although with low yield of extraction. These results will open up possible perspectives for further spectroscopic and structural studies.
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Affiliation(s)
- Cristina Pagliano
- Applied Science and Technology Department-BioSolar Lab, Politecnico di Torino, Viale Teresa Michel 5, 15121 Alessandria, Italy.
| | - Luca Bersanini
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Rino Cella
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Paolo Longoni
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Laura Pantaleoni
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Abhishek Dass
- Plant Transformation Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Sadhu Leelavathi
- Plant Transformation Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Vanga Siva Reddy
- Plant Transformation Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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6
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Ermakova M, Huokko T, Richaud P, Bersanini L, Howe CJ, Lea-Smith DJ, Peltier G, Allahverdiyeva Y. Distinguishing the Roles of Thylakoid Respiratory Terminal Oxidases in the Cyanobacterium Synechocystis sp. PCC 6803. Plant Physiol 2016; 171:1307-19. [PMID: 27208274 PMCID: PMC4902628 DOI: 10.1104/pp.16.00479] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 04/11/2016] [Indexed: 05/03/2023]
Abstract
Various oxygen-utilizing electron sinks, including the soluble flavodiiron proteins (Flv1/3), and the membrane-localized respiratory terminal oxidases (RTOs), cytochrome c oxidase (Cox) and cytochrome bd quinol oxidase (Cyd), are present in the photosynthetic electron transfer chain of Synechocystis sp. PCC 6803. However, the role of individual RTOs and their relative importance compared with other electron sinks are poorly understood, particularly under light. Via membrane inlet mass spectrometry gas exchange, chlorophyll a fluorescence, P700 analysis, and inhibitor treatment of the wild type and various mutants deficient in RTOs, Flv1/3, and photosystem I, we investigated the contribution of these complexes to the alleviation of excess electrons in the photosynthetic chain. To our knowledge, for the first time, we demonstrated the activity of Cyd in oxygen uptake under light, although it was detected only upon inhibition of electron transfer at the cytochrome b6f site and in ∆flv1/3 under fluctuating light conditions, where linear electron transfer was drastically inhibited due to impaired photosystem I activity. Cox is mostly responsible for dark respiration and competes with P700 for electrons under high light. Only the ∆cox/cyd double mutant, but not single mutants, demonstrated a highly reduced plastoquinone pool in darkness and impaired gross oxygen evolution under light, indicating that thylakoid-based RTOs are able to compensate partially for each other. Thus, both electron sinks contribute to the alleviation of excess electrons under illumination: RTOs continue to function under light, operating on slower time ranges and on a limited scale, whereas Flv1/3 responds rapidly as a light-induced component and has greater capacity.
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Affiliation(s)
- Maria Ermakova
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.)
| | - Tuomas Huokko
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.)
| | - Pierre Richaud
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.)
| | - Luca Bersanini
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.)
| | - Christopher J Howe
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.)
| | - David J Lea-Smith
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.)
| | - Gilles Peltier
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.)
| | - Yagut Allahverdiyeva
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland (M.E., T.H., L.B., Y.A.);Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Cadarache, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Centre National de la Recherche Scientifique, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13108 Saint-Paul-lez-Durance, France (P.R., G.P.);Aix Marseille Université, Biologie Végétale et Microbiologie Environnementales, Unité Mixte de Recherche 7265, F-13284 Marseille, France (P.R., G.P.); andDepartment of Biochemistry, University of Cambridge, Cambridge, CB2 1QW United Kingdom (C.J.H., D.J.L.-S.)
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7
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Chukhutsina V, Bersanini L, Aro EM, van Amerongen H. Cyanobacterial flv4-2 Operon-Encoded Proteins Optimize Light Harvesting and Charge Separation in Photosystem II. Mol Plant 2015; 8:747-61. [PMID: 25704162 DOI: 10.1016/j.molp.2014.12.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 12/09/2014] [Accepted: 12/21/2014] [Indexed: 05/11/2023]
Abstract
Photosystem II (PSII) complexes drive the water-splitting reaction necessary to transform sunlight into chemical energy. However, too much light can damage and disrupt PSII. In cyanobacteria, the flv4-2 operon encodes three proteins (Flv2, Flv4, and Sll0218), which safeguard PSII activity under air-level CO2 and in high light conditions. However, the exact mechanism of action of these proteins has not been clarified yet. We demonstrate that the PSII electron transfer properties are influenced by the flv4-2 operon-encoded proteins. Accelerated secondary charge separation kinetics was observed upon expression/overexpression of the flv4-2 operon. This is likely induced by docking of the Flv2/Flv4 heterodimer in the vicinity of the QB pocket of PSII, which, in turn, increases the QB redox potential and consequently stabilizes forward electron transfer. The alternative electron transfer route constituted by Flv2/Flv4 sequesters electrons from QB(-) guaranteeing the dissipation of excess excitation energy in PSII under stressful conditions. In addition, we demonstrate that in the absence of the flv4-2 operon-encoded proteins, about 20% of the phycobilisome antenna becomes detached from the reaction centers, thus decreasing light harvesting. Phycobilisome detachment is a consequence of a decreased relative content of PSII dimers, a feature observed in the absence of the Sll0218 protein.
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Affiliation(s)
- Volha Chukhutsina
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, The Netherlands; MicroSpectroscopy Centre, Wageningen University, 6703HA Wageningen, The Netherlands; BioSolarCells, P.O. Box 98, 6700AB Wageningen, The Netherlands
| | - Luca Bersanini
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, The Netherlands; MicroSpectroscopy Centre, Wageningen University, 6703HA Wageningen, The Netherlands; BioSolarCells, P.O. Box 98, 6700AB Wageningen, The Netherlands.
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8
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Bersanini L, Battchikova N, Jokel M, Rehman A, Vass I, Allahverdiyeva Y, Aro EM. Flavodiiron protein Flv2/Flv4-related photoprotective mechanism dissipates excitation pressure of PSII in cooperation with phycobilisomes in Cyanobacteria. Plant Physiol 2014; 164:805-18. [PMID: 24367022 PMCID: PMC3912107 DOI: 10.1104/pp.113.231969] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 12/16/2013] [Indexed: 05/20/2023]
Abstract
Oxygenic photosynthesis evolved with cyanobacteria, the ancestors of plant chloroplasts. The highly oxidizing chemistry of water splitting required concomitant evolution of efficient photoprotection mechanisms to safeguard the photosynthetic machinery. The role of flavodiiron proteins (FDPs), originally called A-type flavoproteins or Flvs, in this context has only recently been appreciated. Cyanobacterial FDPs constitute a specific protein group that evolved to protect oxygenic photosynthesis. There are four FDPs in Synechocystis sp. PCC 6803 (Flv1 to Flv4). Two of them, Flv2 and Flv4, are encoded by an operon together with a Sll0218 protein. Their expression, tightly regulated by CO2 levels, is also influenced by changes in light intensity. Here we describe the overexpression of the flv4-2 operon in Synechocystis sp. PCC 6803 and demonstrate that it results in improved photochemistry of PSII. The flv4-2/OE mutant is more resistant to photoinhibition of PSII and exhibits a more oxidized state of the plastoquinone pool and reduced production of singlet oxygen compared with control strains. Results of biophysical measurements indicate that the flv4-2 operon functions in an alternative electron transfer pathway from PSII, and thus alleviates PSII excitation pressure by channeling up to 30% of PSII-originated electrons. Furthermore, intact phycobilisomes are required for stable expression of the flv4-2 operon genes and for the Flv2/Flv4 heterodimer-mediated electron transfer mechanism. The latter operates in photoprotection in a complementary way with the orange carotenoid protein-related nonphotochemical quenching. Expression of the flv4-2 operon and exchange of the D1 forms in PSII centers upon light stress, on the contrary, are mutually exclusive photoprotection strategies among cyanobacteria.
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Battchikova N, Wei L, Du L, Bersanini L, Aro EM, Ma W. Identification of novel Ssl0352 protein (NdhS), essential for efficient operation of cyclic electron transport around photosystem I, in NADPH:plastoquinone oxidoreductase (NDH-1) complexes of Synechocystis sp. PCC 6803. J Biol Chem 2012. [DOI: 10.1074/jbc.a111.263780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Battchikova N, Wei L, Du L, Bersanini L, Aro EM, Ma W. Identification of novel Ssl0352 protein (NdhS), essential for efficient operation of cyclic electron transport around photosystem I, in NADPH:plastoquinone oxidoreductase (NDH-1) complexes of Synechocystis sp. PCC 6803. J Biol Chem 2011; 286:36992-7001. [PMID: 21880717 PMCID: PMC3196108 DOI: 10.1074/jbc.m111.263780] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 08/25/2011] [Indexed: 11/06/2022] Open
Abstract
Cyanobacterial NADPH:plastoquinone oxidoreductase, or type I NAD(P)H dehydrogenase, or the NDH-1 complex is involved in plastoquinone reduction and cyclic electron transfer (CET) around photosystem I. CET, in turn, produces extra ATP for cell metabolism particularly under stressful conditions. Despite significant achievements in the study of cyanobacterial NDH-1 complexes during the past few years, the entire subunit composition still remains elusive. To identify missing subunits, we screened a transposon-tagged library of Synechocystis 6803 cells grown under high light. Two NDH-1-mediated CET (NDH-CET)-defective mutants were tagged in the same ssl0352 gene encoding a short unknown protein. To clarify the function of Ssl0352, the ssl0352 deletion mutant and another mutant with Ssl0352 fused to yellow fluorescent protein (YFP) and the His(6) tag were constructed. Immunoblotting, mass spectrometry, and confocal microscopy analyses revealed that the Ssl0352 protein resides in the thylakoid membrane and associates with the NDH-1L and NDH-1M complexes. We conclude that Ssl0352 is a novel subunit of cyanobacterial NDH-1 complexes and designate it NdhS. Deletion of the ssl0352 gene considerably impaired the NDH-CET activity and also retarded cell growth under high light conditions, indicating that NdhS is essential for efficient operation of NDH-CET. However, the assembly of the NDH-1L and NDH-1M complexes and their content in the cells were not affected in the mutant. NdhS contains a Src homology 3-like domain and might be involved in interaction of the NDH-1 complex with an electron donor.
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Affiliation(s)
- Natalia Battchikova
- Department of Biochemistry and Food Chemistry, Molecular Plant Biology, University of Turku, FI-20520 Turku, Finland
| | - Lanzhen Wei
- From the College of Life and Environment Sciences, Shanghai Normal University, Guilin Road 100, Shanghai 200234, China and
| | - Lingyu Du
- From the College of Life and Environment Sciences, Shanghai Normal University, Guilin Road 100, Shanghai 200234, China and
| | - Luca Bersanini
- Department of Biochemistry and Food Chemistry, Molecular Plant Biology, University of Turku, FI-20520 Turku, Finland
| | - Eva-Mari Aro
- Department of Biochemistry and Food Chemistry, Molecular Plant Biology, University of Turku, FI-20520 Turku, Finland
| | - Weimin Ma
- From the College of Life and Environment Sciences, Shanghai Normal University, Guilin Road 100, Shanghai 200234, China and
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