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Pandit A. Structural dynamics of light harvesting proteins, photosynthetic membranes and cells observed with spectral editing solid-state NMR. J Chem Phys 2022; 157:025101. [DOI: 10.1063/5.0094446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photosynthetic light-harvesting complexes have a remarkable capacity to perform robust photo physics at ambient temperatures and in fluctuating environments. Protein conformational dynamics and membrane mobility are processes that contribute to the light-harvesting efficiencies and control photoprotective responses. This short review describes the application of Magic Angle Spinning (MAS) NMR spectroscopy for characterizing the structural dynamics of pigment, protein and thylakoid membrane components related to light harvesting and photoprotection. I will discuss the use of dynamics-based spectral editing solid-state NMR for distinguishing rigid and mobile components and assessing protein, pigment and lipid dynamics on sub-nanosecond to millisecond timescales. Dynamic spectral editing NMR has been applied to investigate Light-Harvesting Complex II (LHCII) protein conformational dynamics inside lipid bilayers and in native membranes. Furthermore, we used the NMR approach to assess thylakoid membrane dynamics. Finally, it is shown that dynamics-based spectral editing NMR, for reducing spectral complexity, by filtering motion-dependent signals, enabled us to follow processes in live photosynthetic cells.
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Nagao R, Yokono M, Ueno Y, Nakajima Y, Suzuki T, Kato KH, Tsuboshita N, Dohmae N, Shen JR, Ehira S, Akimoto S. Excitation-energy transfer in heterocysts isolated from the cyanobacterium Anabaena sp. PCC 7120 as studied by time-resolved fluorescence spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2022; 1863:148509. [PMID: 34793768 DOI: 10.1016/j.bbabio.2021.148509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 10/06/2021] [Accepted: 11/09/2021] [Indexed: 11/18/2022]
Abstract
Heterocysts are formed in filamentous heterocystous cyanobacteria under nitrogen-starvation conditions, and possess a very low amount of photosystem II (PSII) complexes than vegetative cells. Molecular, morphological, and biochemical characterizations of heterocysts have been investigated; however, excitation-energy dynamics in heterocysts are still unknown. In this study, we examined excitation-energy-relaxation processes of pigment-protein complexes in heterocysts isolated from the cyanobacterium Anabaena sp. PCC 7120. Thylakoid membranes from the heterocysts showed no oxygen-evolving activity under our experimental conditions and no thermoluminescence-glow curve originating from charge recombination of S2QA-. Two dimensional blue-native/SDS-PAGE analysis exhibits tetrameric, dimeric, and monomeric photosystem I (PSI) complexes but almost no dimeric and monomeric PSII complexes in the heterocyst thylakoids. The steady-state fluorescence spectrum of the heterocyst thylakoids at 77 K displays both characteristic PSI fluorescence and unusual PSII fluorescence different from the fluorescence of PSII dimer and monomer complexes. Time-resolved fluorescence spectra at 77 K, followed by fluorescence decay-associated spectra, showed different PSII and PSI fluorescence bands between heterocysts and vegetative thylakoids. Based on these findings, we discuss excitation-energy-transfer mechanisms in the heterocysts.
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Affiliation(s)
- Ryo Nagao
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
| | - Makio Yokono
- Institute of Low Temperature Science, Hokkaido University, Hokkaido 060-0819, Japan
| | - Yoshifumi Ueno
- Graduate School of Science, Kobe University, Hyogo 657-8501, Japan
| | - Yoshiki Nakajima
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Takehiro Suzuki
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Saitama 351-0198, Japan
| | - Ka-Ho Kato
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Naoki Tsuboshita
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Saitama 351-0198, Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Shigeki Ehira
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan.
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Hyogo 657-8501, Japan.
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Nagao R, Yokono M, Kato KH, Ueno Y, Shen JR, Akimoto S. High-light modification of excitation-energy-relaxation processes in the green flagellate Euglena gracilis. PHOTOSYNTHESIS RESEARCH 2021; 149:303-311. [PMID: 34037905 DOI: 10.1007/s11120-021-00849-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
Photosynthetic organisms finely tune their photosynthetic machinery including pigment compositions and antenna systems to adapt to various light environments. However, it is poorly understood how the photosynthetic machinery in the green flagellate Euglena gracilis is modified under high-light conditions. In this study, we examined high-light modification of excitation-energy-relaxation processes in Euglena cells. Oxygen-evolving activity in the cells incubated at 300 µmol photons m-2 s-1 (HL cells) cannot be detected, reflecting severe photodamage to photosystem II (PSII) in vivo. Pigment compositions in the HL cells showed relative increases in 9'-cis-neoxanthin, diadinoxanthin, and chlorophyll b compared with the cells incubated at 30 µmol photons m-2 s-1 (LL cells). Absolute fluorescence spectra at 77 K exhibit smaller intensities of the PSII and photosystem I (PSI) fluorescence in the HL cells than in the LL cells. Absolute fluorescence decay-associated spectra at 77 K of the HL cells indicate suppression of excitation-energy transfer from light-harvesting complexes (LHCs) to both PSI and PSII with the time constant of 40 ps. Rapid energy quenching in LHCs and PSII in the HL cells is distinctly observed by averaged Chl-fluorescence lifetimes. These findings suggest that Euglena modifies excitation-energy-relaxation processes in addition to pigment compositions to deal with excess energy. These results provide insights into the photoprotection strategies of this alga under high-light conditions.
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Affiliation(s)
- Ryo Nagao
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
| | - Makio Yokono
- Institute of Low Temperature Science, Hokkaido University, Hokkaido, 060-0819, Japan
| | - Ka-Ho Kato
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Yoshifumi Ueno
- Graduate School of Science, Kobe University, Hyogo, 657-8501, Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Hyogo, 657-8501, Japan.
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Nami F, Tian L, Huber M, Croce R, Pandit A. Lipid and protein dynamics of stacked and cation-depletion induced unstacked thylakoid membranes. BBA ADVANCES 2021; 1:100015. [PMID: 37082020 PMCID: PMC10074959 DOI: 10.1016/j.bbadva.2021.100015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chloroplast thylakoid membranes in plants and green algae form 3D architectures of stacked granal membranes interconnected by unstacked stroma lamellae. They undergo dynamic structural changes as a response to changing light conditions that involve grana unstacking and lateral supramolecular reorganization of the integral membrane protein complexes. We assessed the dynamics of thylakoid membrane components and addressed how they are affected by thylakoid unstacking, which has consequences for protein mobility and the diffusion of small electron carriers. By a combined nuclear and electron paramagnetic-resonance approach the dynamics of thylakoid lipids was assessed in stacked and cation-depletion induced unstacked thylakoids of Chlamydomonas (C.) reinhardtii. We could distinguish between structural, bulk and annular lipids and determine membrane fluidity at two membrane depths: close to the lipid headgroups and in the lipid bilayer center. Thylakoid unstacking significantly increased the dynamics of bulk and annular lipids in both areas and increased the dynamics of protein helices. The unstacking process was associated with membrane reorganization and loss of long-range ordered Photosystem II- Light-Harvesting Complex II (PSII-LHCII) complexes. The fluorescence lifetime characteristics associated with membrane unstacking are similar to those associated with state transitions in intact C. reinhardtii cells. Our findings could be relevant for understanding the structural and functional implications of thylakoid unstacking that is suggested to take place during several light-induced processes, such as state transitions, photoacclimation, photoinhibition and PSII repair.
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Affiliation(s)
- Faezeh Nami
- Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Lijin Tian
- Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Martina Huber
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2300 RA, Leiden, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy, VU University Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Anjali Pandit
- Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
- Corresponding author:
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Molecular organizations and function of iron-stress-induced-A protein family in Anabaena sp. PCC 7120. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148327. [PMID: 33069682 DOI: 10.1016/j.bbabio.2020.148327] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/29/2020] [Accepted: 10/13/2020] [Indexed: 11/22/2022]
Abstract
Iron-stress-induced-A proteins (IsiAs) are expressed in cyanobacteria under iron-deficient conditions, and surround photosystem I (PSI) trimer with a ring formation. A cyanobacterium Anabaena sp. PCC 7120 has four isiA genes; however, it is unknown how the IsiAs are associated with PSI. Here we report on molecular organizations and function of the IsiAs in this cyanobacterium. A deletion mutant of the isiA1 gene was constructed, and the four types of thylakoids were prepared from the wild-type (WT) and ΔisiA1 cells under iron-replete (+Fe) and iron-deficient (-Fe) conditions. Immunoblotting analysis exhibits a clear expression of the IsiA1 in the WT-Fe. The PSI-IsiA1 supercomplex is found in the WT-Fe, and excitation-energy transfer from IsiA1 to PSI is verified by time-resolved fluorescence analyses. Instead of the IsiA1, both IsiA2 and IsiA3 are bound to PSI monomer in the ΔisiA1-Fe. These findings provide insights into multiple-expression system of the IsiA family in this cyanobacterium.
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Lattice Models for Protein Organization throughout Thylakoid Membrane Stacks. Biophys J 2020; 118:2680-2693. [PMID: 32413311 DOI: 10.1016/j.bpj.2020.03.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 03/14/2020] [Accepted: 03/24/2020] [Indexed: 11/21/2022] Open
Abstract
Proteins in photosynthetic membranes can organize into patterned arrays that span the membrane's lateral size. Attractions between proteins in different layers of a membrane stack can play a key role in this ordering, as was suggested by microscopy and fluorescence spectroscopy and demonstrated by computer simulations of a coarse-grained model. The architecture of thylakoid membranes, however, also provides opportunities for interlayer interactions that instead disfavor the high protein densities of ordered arrangements. Here, we explore the interplay between these opposing driving forces and, in particular, the phase transitions that emerge in the periodic geometry of stacked thylakoid membrane disks. We propose a lattice model that roughly accounts for proteins' attraction within a layer and across the stromal gap, steric repulsion across the lumenal gap, and regulation of protein density by exchange with the stroma lamellae. Mean-field analysis and computer simulation reveal rich phase behavior for this simple model, featuring a broken-symmetry striped phase that is disrupted at both high and low extremes of chemical potential. The resulting sensitivity of microscopic protein arrangement to the thylakoid's mesoscale vertical structure raises intriguing possibilities for regulation of photosynthetic function.
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Ueno Y, Shimakawa G, Aikawa S, Miyake C, Akimoto S. Photoprotection mechanisms under different CO 2 regimes during photosynthesis in a green alga Chlorella variabilis. PHOTOSYNTHESIS RESEARCH 2020; 144:397-407. [PMID: 32377933 DOI: 10.1007/s11120-020-00757-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 04/23/2020] [Indexed: 05/28/2023]
Abstract
Oxygenic photosynthesis converts light energy into chemical energy via electron transport and assimilates CO2 in the Calvin-Benson cycle with the chemical energy. Thus, high light and low CO2 conditions induce the accumulation of electrons in the photosynthetic electron transport system, resulting in the formation of reactive oxygen species. To prevent the accumulation of electrons, oxygenic photosynthetic organisms have developed photoprotection mechanisms, including non-photochemical quenching (NPQ) and alternative electron flow (AEF). There are diverse molecular mechanisms underlying NPQ and AEF, and the corresponding molecular actors have been identified and characterized using a model green alga Chlamydomonas reinhardtii. In contrast, detailed information about the photoprotection mechanisms is lacking for other green algal species. In the current study, we examined the photoprotection mechanisms responsive to CO2 in the green alga Chlorella variabilis by combining the analyses of pulse-amplitude-modulated fluorescence, O2 evolution, and the steady-state and time-resolved fluorescence spectra. Under the CO2-limited condition, ΔpH-dependent NPQ occurred in photosystems I and II. Moreover, O2-dependent AEF was also induced. Under the CO2-limited condition with carbon supplementation, NPQ was relaxed and light-harvesting chlorophyll-protein complex II was isolated from both photosystems. In C. variabilis, the O2-dependent AEF and the mechanisms that instantly convert the light-harvesting functions of both photosystems may be important for maintaining efficient photosynthetic activities under various CO2 conditions.
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Affiliation(s)
- Yoshifumi Ueno
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
| | - Ginga Shimakawa
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
- Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Shimpei Aikawa
- Japan International Research Center for Agricultural Sciences, Tsukuba, 305-8686, Japan
| | - Chikahiro Miyake
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
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Structure of a cyanobacterial photosystem I surrounded by octadecameric IsiA antenna proteins. Commun Biol 2020; 3:232. [PMID: 32393811 PMCID: PMC7214436 DOI: 10.1038/s42003-020-0949-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 04/17/2020] [Indexed: 11/13/2022] Open
Abstract
Iron-stress induced protein A (IsiA) is a chlorophyll-binding membrane-spanning protein in photosynthetic prokaryote cyanobacteria, and is associated with photosystem I (PSI) trimer cores, but its structural and functional significance in light harvesting remains unclear. Here we report a 2.7-Å resolution cryo-electron microscopic structure of a supercomplex between PSI core trimer and IsiA from a thermophilic cyanobacterium Thermosynechococcus vulcanus. The structure showed that 18 IsiA subunits form a closed ring surrounding a PSI trimer core. Detailed arrangement of pigments within the supercomplex, as well as molecular interactions between PSI and IsiA and among IsiAs, were resolved. Time-resolved fluorescence spectra of the PSI–IsiA supercomplex showed clear excitation-energy transfer from IsiA to PSI, strongly indicating that IsiA functions as an energy donor, but not an energy quencher, in the supercomplex. These structural and spectroscopic findings provide important insights into the excitation-energy-transfer and subunit assembly mechanisms in the PSI–IsiA supercomplex. Akita et al. present the latest approach to solve IsiA–PSI supercomplex molecular structure with increased resolution using cryo-EM and time-resolved fluorescence studies. With 2.7 Å resolution, they reveal molecular interactions between PSI and IsiA subunits and that IsiA functions as an energy donor in the supercomplex.
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Biswas A, Huang X, Lambrev PH, van Stokkum IHM. Modelling excitation energy transfer and trapping in the filamentous cyanobacterium Anabaena variabilis PCC 7120. PHOTOSYNTHESIS RESEARCH 2020; 144:261-272. [PMID: 32076914 PMCID: PMC7203589 DOI: 10.1007/s11120-020-00723-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 02/11/2020] [Indexed: 05/28/2023]
Abstract
The phycobilisome (PBS) serves as the major light-harvesting system, funnelling excitation energy to both photosystems (PS) in cyanobacteria and red algae. The picosecond kinetics involving the excitation energy transfer has been studied within the isolated systems and intact filaments of the cyanobacterium Anabaena variabilis PCC 7120. A target model is proposed which resolves the dynamics of the different chromophore groups. The energy transfer rate of 8.5 ± 1.0/ns from the rod to the core is the rate-limiting step, both in vivo and in vitro. The PBS-PSI-PSII supercomplex reveals efficient excitation energy migration from the low-energy allophycocyanin, which is the terminal emitter, in the PBS core to the chlorophyll a in the photosystems. The terminal emitter of the phycobilisome transfers energy to both PSI and PSII with a rate of 50 ± 10/ns, equally distributing the solar energy to both photosystems. Finally, the excitation energy is trapped by charge separation in the photosystems with trapping rates estimated to be 56 ± 6/ns in PSI and 14 ± 2/ns in PSII.
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Affiliation(s)
- Avratanu Biswas
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
- Biological Research Centre, Szeged, Temesvári krt. 62, Szeged, 6726, Hungary
| | - Xinpeng Huang
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Petar H Lambrev
- Biological Research Centre, Szeged, Temesvári krt. 62, Szeged, 6726, Hungary
| | - Ivo H M van Stokkum
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
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Nagao R, Yokono M, Ueno Y, Jiang TY, Shen JR, Akimoto S. pH-Induced Regulation of Excitation Energy Transfer in the Cyanobacterial Photosystem I Tetramer. J Phys Chem B 2020; 124:1949-1954. [DOI: 10.1021/acs.jpcb.0c01136] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryo Nagao
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Makio Yokono
- Innovation Center, Nippon Flour Mills Company, Ltd., Atsugi 243-0041, Japan
| | - Yoshifumi Ueno
- Graduate School of Science, Kobe University, Kobe 657-8501, Japan
| | - Tian-Yi Jiang
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Kobe 657-8501, Japan
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Nagao R, Ueno Y, Yokono M, Shen JR, Akimoto S. Effects of excess light energy on excitation-energy dynamics in a pennate diatom Phaeodactylum tricornutum. PHOTOSYNTHESIS RESEARCH 2019; 141:355-365. [PMID: 30993504 DOI: 10.1007/s11120-019-00639-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/04/2019] [Indexed: 05/12/2023]
Abstract
Controlling excitation energy flow is a fundamental ability of photosynthetic organisms to keep a better performance of photosynthesis. Among the organisms, diatoms have unique light-harvesting complexes, fucoxanthin chlorophyll (Chl) a/c-binding proteins. We have recently investigated light-adaptation mechanisms of a marine centric diatom, Chaetoceros gracilis, by spectroscopic techniques. However, it remains unclear how pennate diatoms regulate excitation energy under different growth light conditions. Here, we studied light-adaptation mechanisms in a marine pennate diatom Phaeodactylum tricornutum grown at 30 µmol photons m-2 s-1 and further incubated for 24 h either in the dark, or at 30 or 300 µmol photons m-2 s-1 light intensity, by time-resolved fluorescence (TRF) spectroscopy. The high-light incubated cells showed no detectable oxygen-evolving activity of photosystem II, indicating the occurrence of a severe photodamage. The photodamaged cells showed alterations of steady-state absorption and fluorescence spectra and TRF spectra compared with the dark and low-light adapted cells. In particular, excitation-energy quenching is significantly accelerated in the photodamaged cells as shown by mean lifetime analysis of the Chl fluorescence. These spectral changes by the high-light treatment may result from arrangements of pigment-protein complexes to maintain the photosynthetic performance under excess light illumination. These growth-light dependent spectral properties in P. tricornutum are largely different from those in C. gracilis, thus providing insights into the different light-adaptation mechanisms between the pennate and centric diatoms.
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Affiliation(s)
- Ryo Nagao
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
| | - Yoshifumi Ueno
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Makio Yokono
- Nippon Flour Mills Co., Ltd, Innovation Center, Atsugi, 243-0041, Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
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Nagao R, Yokono M, Ueno Y, Shen JR, Akimoto S. pH-Sensing Machinery of Excitation Energy Transfer in Diatom PSI-FCPI Complexes. J Phys Chem Lett 2019; 10:3531-3535. [PMID: 31192608 DOI: 10.1021/acs.jpclett.9b01314] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Excitation energy-transfer processes in photosynthetic light-harvesting complexes are strongly affected by the surrounding environments of pigments. Here we report on the effects of pH changes on excitation energy dynamics in both diatom photosystem I-fucoxanthin chlorophyll a/ c-binding protein (PSI-FCPI) and PSI core complexes by means of fluorescence spectroscopies. The steady-state fluorescence spectra of the PSI-FCPI showed similar features among three samples at pH 5.0, 6.5, and 8.0. However, fluorescence decay-associated spectra of the pH 5.0- and 8.0-adapted PSI-FCPI within 100 ps exhibit peak shifts to longer and shorter wavelengths, respectively, than the peaks in the pH 6.5 spectra. Because such spectral changes hardly occur in the PSI complexes, the peak shifts at pH 5.0 and 8.0 in the PSI-FCPI can be ascribed to alterations of pigment-pigment and/or pigment-protein interactions around/within FCPI caused by the pH changes. These findings provide novel physical insights into the pH-sensing light-harvesting strategy in diatom PSI-FCPI.
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Affiliation(s)
- Ryo Nagao
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - Makio Yokono
- Innovation Center , Nippon Flour Mills Co., Ltd. , Atsugi 243-0041 , Japan
| | - Yoshifumi Ueno
- Graduate School of Science , Kobe University , Kobe 657-8501 , Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - Seiji Akimoto
- Graduate School of Science , Kobe University , Kobe 657-8501 , Japan
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Chukhutsina VU, Holzwarth AR, Croce R. Time-resolved fluorescence measurements on leaves: principles and recent developments. PHOTOSYNTHESIS RESEARCH 2019; 140:355-369. [PMID: 30478711 PMCID: PMC6509100 DOI: 10.1007/s11120-018-0607-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 11/15/2018] [Indexed: 05/03/2023]
Abstract
Photosynthesis starts when a pigment in the photosynthetic antennae absorbs a photon. The electronic excitation energy is then transferred through the network of light-harvesting pigments to special chlorophyll (Chl) molecules in the reaction centres, where electron transfer is initiated. Energy transfer and primary electron transfer processes take place on timescales ranging from femtoseconds to nanoseconds, and can be monitored in real time via time-resolved fluorescence spectroscopy. This method is widely used for measurements on unicellular photosynthetic organisms, isolated photosynthetic membranes, and individual complexes. Measurements on intact leaves remain a challenge due to their high structural heterogeneity, high scattering, and high optical density, which can lead to optical artefacts. However, detailed information on the dynamics of these early steps, and the underlying structure-function relationships, is highly informative and urgently required in order to get deeper insights into the physiological regulation mechanisms of primary photosynthesis. Here, we describe a current methodology of time-resolved fluorescence measurements on intact leaves in the picosecond to nanosecond time range. Principles of fluorescence measurements on intact leaves, possible sources of alterations of fluorescence kinetics and the ways to overcome them are addressed. We also describe how our understanding of the organisation and function of photosynthetic proteins and energy flow dynamics in intact leaves can be enriched through the application of time-resolved fluorescence spectroscopy on leaves. For that, an example of a measurement on Zea mays leaves is presented.
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Affiliation(s)
- Volha U Chukhutsina
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Alfred R Holzwarth
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Roberta Croce
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV, Amsterdam, The Netherlands.
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Ueno Y, Aikawa S, Kondo A, Akimoto S. Adaptation of light-harvesting functions of unicellular green algae to different light qualities. PHOTOSYNTHESIS RESEARCH 2019; 139:145-154. [PMID: 29808364 DOI: 10.1007/s11120-018-0523-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/20/2018] [Indexed: 06/08/2023]
Abstract
Oxygenic photosynthetic organisms perform photosynthesis efficiently by distributing captured light energy to photosystems (PSs) at an appropriate balance. Maintaining photosynthetic efficiency under changing light conditions requires modification of light-harvesting and energy-transfer processes. In the current study, we examined how green algae regulate their light-harvesting functions in response to different light qualities. We measured low-temperature time-resolved fluorescence spectra of unicellular green algae Chlamydomonas reinhardtii and Chlorella variabilis cells grown under different light qualities. By observing the delayed fluorescence spectra, we demonstrated that both types of green algae primarily modified the associations between light-harvesting chlorophyll protein complexes (LHCs) and PSs (PSII and PSI). Under blue light, Chlamydomonas transferred more energy from LHC to chlorophyll (Chl) located far from the PSII reaction center, while energy was transferred from LHC to PSI via different energy-transfer pathways in Chlorella. Under green light, both green algae exhibited enhanced energy transfer from LHCs to both PSs. Red light induced fluorescence quenching within PSs in Chlamydomonas and LHCs in Chlorella. In Chlorella, energy transfer from PSII to PSI appears to play an important role in balancing excitation between PSII and PSI.
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Affiliation(s)
- Yoshifumi Ueno
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Shimpei Aikawa
- Japan International Research Center for Agricultural Sciences, Tsukuba, 305-8686, Japan
| | - Akihiko Kondo
- Graduate School of Science, Technology and Innovation, Kobe University, Kobe, 657-8501, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
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LHCSR3 is a nonphotochemical quencher of both photosystems in Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2019; 116:4212-4217. [PMID: 30782831 DOI: 10.1073/pnas.1809812116] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Photosynthetic organisms prevent oxidative stress from light energy absorbed in excess through several photoprotective mechanisms. A major component is thermal dissipation of chlorophyll singlet excited states and is called nonphotochemical quenching (NPQ). NPQ is catalyzed in green algae by protein subunits called LHCSRs (Light Harvesting Complex Stress Related), homologous to the Light Harvesting Complexes (LHC), constituting the antenna system of both photosystem I (PSI) and PSII. We investigated the role of LHCSR1 and LHCSR3 in NPQ activation to verify whether these proteins are involved in thermal dissipation of PSI excitation energy, in addition to their well-known effect on PSII. To this aim, we measured the fluorescence emitted at 77 K by whole cells in a quenched or unquenched state, using green fluorescence protein as the internal standard. We show that NPQ activation by high light treatment in Chlamydomonas reinhardtii leads to energy quenching in both PSI and PSII antenna systems. By analyzing quenching properties of mutants affected on the expression of LHCSR1 or LHCSR3 gene products and/or state 1-state 2 transitions or zeaxanthin accumulation, namely, npq4, stt7, stt7 npq4, npq4 lhcsr1, lhcsr3-complemented npq4 lhcsr1 and npq1, we showed that PSI undergoes NPQ through quenching of the associated LHCII antenna. This quenching event is fast-reversible on switching the light off, is mainly related to LHCSR3 activity, and is dependent on thylakoid luminal pH. Moreover, PSI quenching could also be observed in the absence of zeaxanthin or STT7 kinase activity.
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Nagao R, Yokono M, Ueno Y, Shen JR, Akimoto S. Low-Energy Chlorophylls in Fucoxanthin Chlorophyll a/c-Binding Protein Conduct Excitation Energy Transfer to Photosystem I in Diatoms. J Phys Chem B 2018; 123:66-70. [DOI: 10.1021/acs.jpcb.8b09253] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryo Nagao
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Makio Yokono
- Nippon Flour Mills Co., Ltd., Innovation Center, Atsugi 243-0041, Japan
| | - Yoshifumi Ueno
- Graduate School of Science, Kobe University, Kobe 657-8501, Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Kobe 657-8501, Japan
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Wlodarczyk LM, Snellenburg JJ, Dekker JP, Stokkum IHM. Development of fluorescence quenching in Chlamydomonas reinhardtii upon prolonged illumination at 77 K. PHOTOSYNTHESIS RESEARCH 2018; 137:503-513. [PMID: 29948747 PMCID: PMC6182390 DOI: 10.1007/s11120-018-0534-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
Low-temperature fluorescence measurements are frequently used in photosynthesis research to assess photosynthetic processes. Upon illumination of photosystem II (PSII) frozen to 77 K, fluorescence quenching is observed. In this work, we studied the light-induced quenching in intact cells of Chlamydomonas reinhardtii at 77 K using time-resolved fluorescence spectroscopy with a streak camera setup. In agreement with previous studies, global analysis of the data shows that prolonged illumination of the sample affects the nanosecond decay component of the PSII emission. Using target analysis, we resolved the quenching on the PSII-684 compartment which describes bulk chlorophyll molecules of the PSII core antenna. Further, we quantified the quenching rate constant and observed that as the illumination proceeds the accumulation of the quencher leads to a speed up of the fluorescence decay of the PSII-684 compartment as the decay rate constant increases from about 3 to 4 ns- 1. The quenching on PSII-684 leads to indirect quenching of the compartments PSII-690 and PSII-695 which represent the red chlorophyll of the PSII core. These results explain past and current observations of light-induced quenching in 77 K steady-state and time-resolved fluorescence spectra.
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Affiliation(s)
- Lucyna M Wlodarczyk
- LaserLaB, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Joris J Snellenburg
- LaserLaB, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Jan P Dekker
- LaserLaB, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Ivo H M Stokkum
- LaserLaB, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
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18
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Alterations of pigment composition and their interactions in response to different light conditions in the diatom Chaetoceros gracilis probed by time-resolved fluorescence spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:524-530. [DOI: 10.1016/j.bbabio.2018.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/17/2018] [Accepted: 04/10/2018] [Indexed: 01/02/2023]
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Ueno Y, Shimakawa G, Miyake C, Akimoto S. Light-Harvesting Strategy during CO 2-Dependent Photosynthesis in the Green Alga Chlamydomonas reinhardtii. J Phys Chem Lett 2018; 9:1028-1033. [PMID: 29425442 DOI: 10.1021/acs.jpclett.7b03404] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
To maximize the efficiency of photosynthesis, photosynthetic organisms must properly balance their light-harvesting ability and CO2 utilization. However, the molecular mechanisms of light harvesting under various CO2 conditions remain unclear. To reveal these mechanisms, we performed new analysis on cells of the green alga Chlamydomonas reinhardtii under different CO2 conditions. The analysis combines three kinds of fluorometries: pulse-amplitude modulated fluorescence, steady-state fluorescence with absolute intensity, and time-resolved fluorescence. Under low CO2 conditions, the main regulatory mechanism was migration of a light-harvesting chlorophyll-protein complex (LHC) II from photosystem (PS) II to PSI. However, under CO2-deficient conditions with carbon supplementation, some of the LHCII separated from the PSI and aggregated with quenching. These different light-harvesting abilities of LHCII may play an important role in the regulation of light harvesting in C. reinhardtii under various CO2 conditions.
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Affiliation(s)
- Yoshifumi Ueno
- Graduate School of Science, Kobe University , Kobe 657-8501, Japan
| | - Ginga Shimakawa
- Graduate School of Agricultural Science, Kobe University , Kobe 657-8501, Japan
| | - Chikahiro Miyake
- Graduate School of Agricultural Science, Kobe University , Kobe 657-8501, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University , Kobe 657-8501, Japan
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20
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Acuña AM, Lemaire C, van Grondelle R, Robert B, van Stokkum IHM. Energy transfer and trapping in Synechococcus WH 7803. PHOTOSYNTHESIS RESEARCH 2018; 135:115-124. [PMID: 29030777 PMCID: PMC5784009 DOI: 10.1007/s11120-017-0451-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/26/2017] [Indexed: 05/28/2023]
Abstract
Excitation energy transfer (EET) and trapping in Synechococcus WH 7803 whole cells and isolated photosystem I (PSI) complexes have been studied by time-resolved emission spectroscopy at room temperature (RT) and at 77 K. With the help of global and target analysis, the pathways of EET and the charge separation dynamics have been identified. Energy absorbed in the phycobilisome (PB) rods by the abundant phycoerythrin (PE) is funneled to phycocyanin (PC645) and from there to the core that contains allophycocyanin (APC660 and APC680). Intra-PB EET rates have been estimated to range from 11 to 68/ns. It was estimated that at RT, the terminal emitter of the phycobilisome, APC680, transfers its energy at a rate of 90/ns to PSI and at a rate of 50/ns to PSII. At 77 K, the redshifted Chl a states in the PSI core were heterogeneous, with maximum emission at 697 and 707 nm. In 72% of the PSI complexes, the bulk Chl a in equilibrium with F697 decayed with a main trapping lifetime of 39 ps.
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Affiliation(s)
- Alonso M Acuña
- Faculty of Science, Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Vrije Universiteit, Amsterdam, Netherlands
| | - Claire Lemaire
- CEA, Institut de Biologie et de Technologies de Saclay, and CNRS, 91191, Gif/Yvette Cedex, France
| | - Rienk van Grondelle
- Faculty of Science, Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Vrije Universiteit, Amsterdam, Netherlands
| | - Bruno Robert
- Faculty of Science, Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Vrije Universiteit, Amsterdam, Netherlands
- CEA, Institut de Biologie et de Technologies de Saclay, and CNRS, 91191, Gif/Yvette Cedex, France
| | - Ivo H M van Stokkum
- Faculty of Science, Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Vrije Universiteit, Amsterdam, Netherlands.
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Düner M, Lambertz J, Mügge C, Hemschemeier A. The soluble guanylate cyclase CYG12 is required for the acclimation to hypoxia and trophic regimes in Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:311-337. [PMID: 29161457 DOI: 10.1111/tpj.13779] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/03/2017] [Accepted: 11/09/2017] [Indexed: 05/27/2023]
Abstract
Oxygenic phototrophs frequently encounter environmental conditions that result in intracellular energy crises. Growth of the unicellular green alga Chlamydomonas reinhardtii in hypoxia in the light depends on acclimatory responses of which the induction of photosynthetic cyclic electron flow is essential. The microalga cannot grow in the absence of molecular oxygen (O2 ) in the dark, although it possesses an elaborate fermentation metabolism. Not much is known about how the microalga senses and signals the lack of O2 or about its survival strategies during energy crises. Recently, nitric oxide (NO) has emerged to be required for the acclimation of C. reinhardtii to hypoxia. In this study, we show that the soluble guanylate cyclase (sGC) CYG12, a homologue of animal NO sensors, is also involved in this response. CYG12 is an active sGC, and post-transcriptional down-regulation of the CYG12 gene impairs hypoxic growth and gene expression in C. reinhardtii. However, it also results in a disturbed photosynthetic apparatus under standard growth conditions and the inability to grow heterotrophically. Transcriptome profiles indicate that the mis-expression of CYG12 results in a perturbation of responses that, in the wild-type, maintain the cellular energy budget. We suggest that CYG12 is required for the proper operation of the photosynthetic apparatus which, in turn, is essential for survival in hypoxia and darkness.
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Affiliation(s)
- Melis Düner
- Department of Plant Biochemistry, Workgroup Photobiotechnology, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Jan Lambertz
- Department of Plant Biochemistry, Workgroup Photobiotechnology, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Carolin Mügge
- Junior Research Group for Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Anja Hemschemeier
- Department of Plant Biochemistry, Workgroup Photobiotechnology, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, 44801, Bochum, Germany
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Chukhutsina VU, Fristedt R, Morosinotto T, Croce R. Photoprotection strategies of the alga Nannochloropsis gaditana. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:544-552. [DOI: 10.1016/j.bbabio.2017.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 05/03/2017] [Accepted: 05/07/2017] [Indexed: 01/02/2023]
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23
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Snellenburg JJ, Wlodarczyk LM, Dekker JP, van Grondelle R, van Stokkum IH. A model for the 77 K excited state dynamics in Chlamydomonas reinhardtii in state 1 and state 2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:64-72. [DOI: 10.1016/j.bbabio.2016.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/06/2016] [Accepted: 10/07/2016] [Indexed: 01/28/2023]
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