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Yong S, Chen Q, Xu F, Fu H, Liang G, Guo Q. Exploring the interplay between angiosperm chlorophyll metabolism and environmental factors. PLANTA 2024; 260:25. [PMID: 38861219 PMCID: PMC11166782 DOI: 10.1007/s00425-024-04437-8] [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: 04/15/2024] [Accepted: 05/09/2024] [Indexed: 06/12/2024]
Abstract
MAIN CONCLUSION In this review, we summarize how chlorophyll metabolism in angiosperm is affected by the environmental factors: light, temperature, metal ions, water, oxygen, and altitude. The significance of chlorophyll (Chl) in plant leaf morphogenesis and photosynthesis cannot be overstated. Over time, researchers have made significant advancements in comprehending the biosynthetic pathway of Chl in angiosperms, along with the pivotal enzymes and genes involved in this process, particularly those related to heme synthesis and light-responsive mechanisms. Various environmental factors influence the stability of Chl content in angiosperms by modulating Chl metabolic pathways. Understanding the interplay between plants Chl metabolism and environmental factors has been a prominent research topic. This review mainly focuses on angiosperms, provides an overview of the regulatory mechanisms governing Chl metabolism, and the impact of environmental factors such as light, temperature, metal ions (iron and magnesium), water, oxygen, and altitude on Chl metabolism. Understanding these effects is crucial for comprehending and preserving the homeostasis of Chl metabolism.
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Affiliation(s)
- Shunyuan Yong
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, People's Republic of China
- State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences of Southwest University, Chongqing, 400715, People's Republic of China
| | - Qian Chen
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, People's Republic of China
- State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences of Southwest University, Chongqing, 400715, People's Republic of China
| | - Fan Xu
- College of Agronomy and Biotechnology, Southwest University, Chongqing, 400715, People's Republic of China
| | - Hao Fu
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, People's Republic of China
- State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences of Southwest University, Chongqing, 400715, People's Republic of China
| | - Guolu Liang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, People's Republic of China
- State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences of Southwest University, Chongqing, 400715, People's Republic of China
| | - Qigao Guo
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, People's Republic of China.
- State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences of Southwest University, Chongqing, 400715, People's Republic of China.
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Santabarbara S, Agostini A, Petrova AA, Bortolus M, Casazza AP, Carbonera D. Chlorophyll triplet states in thylakoid membranes of Acaryochloris marina. Evidence for a triplet state sitting on the photosystem I primary donor populated by intersystem crossing. PHOTOSYNTHESIS RESEARCH 2024; 159:133-152. [PMID: 37191762 DOI: 10.1007/s11120-023-01023-z] [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: 03/16/2023] [Accepted: 04/27/2023] [Indexed: 05/17/2023]
Abstract
Photo-induced triplet states in the thylakoid membranes isolated from the cyanobacterium Acaryocholoris marina, that harbours Chlorophyll (Chl) d as its main chromophore, have been investigated by Optically Detected Magnetic Resonance (ODMR) and time-resolved Electron Paramagnetic Resonance (TR-EPR). Thylakoids were subjected to treatments aimed at poising the redox state of the terminal electron transfer acceptors and donors of Photosystem II (PSII) and Photosystem I (PSI), respectively. Under ambient redox conditions, four Chl d triplet populations were detectable, identifiable by their characteristic zero field splitting parameters, after deconvolution of the Fluorescence Detected Magnetic Resonance (FDMR) spectra. Illumination in the presence of the redox mediator N,N,N',N'-Tetramethyl-p-phenylenediamine (TMPD) and sodium ascorbate at room temperature led to a redistribution of the triplet populations, with T3 (|D|= 0.0245 cm-1, |E|= 0.0042 cm-1) becoming dominant and increasing in intensity with respect to untreated samples. A second triplet population (T4, |D|= 0.0248 cm-1, |E|= 0.0040 cm-1) having an intensity ratio of about 1:4 with respect to T3 was also detectable after illumination in the presence of TMPD and ascorbate. The microwave-induced Triplet-minus-Singlet spectrum acquired at the maximum of the |D|-|E| transition (610 MHz) displays a broad minimum at 740 nm, accompanied by a set of complex spectral features that overall resemble, despite showing further fine spectral structure, the previously reported Triplet-minus-Singlet spectrum attributed to the recombination triplet of PSI reaction centre,3 P 740 [Schenderlein M, Çetin M, Barber J, et al. Spectroscopic studies of the chlorophyll d containing photosystem I from the cyanobacterium Acaryochloris marina. Biochim Biophys Acta 1777:1400-1408]. However, TR-EPR experiments indicate that this triplet displays an eaeaea electron spin polarisation pattern which is characteristic of triplet sublevels populated by intersystem crossing rather than recombination, for which an aeeaae polarisation pattern is expected instead. It is proposed that the observed triplet, which leads to the bleaching of the P740 singlet state, sits on the PSI reaction centre.
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Affiliation(s)
- Stefano Santabarbara
- Photosynthesis Research Unit, Centro Studi Sulla Biologia Cellulare e Molecolare delle Piante, Consiglio Nazionale Delle Ricerche, Via Celoria 26, 20133, Milan, Italy.
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133, Milan, Italy.
| | - Alessandro Agostini
- Department of Chemical Sciences, Università di Padova, Via Marzolo 1, 35131, Padua, Italy
| | - Anastasia A Petrova
- Photosynthesis Research Unit, Centro Studi Sulla Biologia Cellulare e Molecolare delle Piante, Consiglio Nazionale Delle Ricerche, Via Celoria 26, 20133, Milan, Italy
- A. N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskye Gory 1 Building 40, Moscow, Russia, 119992
| | - Marco Bortolus
- Department of Chemical Sciences, Università di Padova, Via Marzolo 1, 35131, Padua, Italy
| | - Anna Paola Casazza
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133, Milan, Italy
| | - Donatella Carbonera
- Department of Chemical Sciences, Università di Padova, Via Marzolo 1, 35131, Padua, Italy.
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3
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Alster J, Bína D, Charvátová K, Lokstein H, Pšenčík J. Direct observation of triplet energy transfer between chlorophylls and carotenoids in the core antenna of photosystem I from Thermosynechococcus elongatus. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149016. [PMID: 37832862 DOI: 10.1016/j.bbabio.2023.149016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/29/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023]
Abstract
Quenching of chlorophyll triplet states by carotenoids is an essential photoprotective process, which prevents formation of reactive singlet oxygen in photosynthetic light-harvesting complexes. The process is usually very efficient in oxygenic organisms under physiological conditions, thus preventing any observable accumulation of chlorophyll triplets. However, it subsequently prevents also the determination of the triplet transfer rate. Here we report results of nanosecond transient absorption spectroscopy on photosystem I core complexes, where a major part of chlorophyll a triplet states (~60 %) accumulates on a nanosecond time scale at ambient temperature. As a consequence, the triplet energy transfer could be resolved and the transfer time was determined to be about 24 ns. A smaller fraction of chlorophyll a triplet states (~40 %) is quenched with a faster rate, which could not be determined. Our analysis indicates that these chlorophylls are in direct contact with carotenoids. The overall chlorophyll triplet yield in the core antenna was estimated to be ~0.3 %, which is a value two orders of magnitude smaller than in most other photosynthetic light-harvesting complexes. This explains why slower quenching of chlorophyll triplet states is sufficient for photoprotection of photosystem I. Nevertheless, the core antenna of photosystem I represents one of only few photosynthetic complexes of oxygenic organisms in which the quenching rate of the majority of chlorophyll triplets can be directly monitored under physiological temperature.
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Affiliation(s)
- J Alster
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - D Bína
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic; Biology Centre, Czech Academy of Science, České Budějovice, Czech Republic
| | - K Charvátová
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - H Lokstein
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - J Pšenčík
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic.
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4
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Agostini A, Shen G, Bryant DA, Golbeck JH, van der Est A, Carbonera D. Optically detected magnetic resonance and mutational analysis reveal significant differences in the photochemistry and structure of chlorophyll f synthase and photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:149002. [PMID: 37562512 DOI: 10.1016/j.bbabio.2023.149002] [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: 05/29/2023] [Revised: 07/24/2023] [Accepted: 07/31/2023] [Indexed: 08/12/2023]
Abstract
In cyanobacteria that undergo far red light photoacclimation (FaRLiP), chlorophyll (Chl) f is produced by the ChlF synthase enzyme, probably by photo-oxidation of Chl a. The enzyme forms homodimeric complexes and the primary amino acid sequence of ChlF shows a high degree of homology with the D1 subunit of photosystem II (PSII). However, few details of the photochemistry of ChlF are known. The results of a mutational analysis and optically detected magnetic resonance (ODMR) data from ChlF are presented. Both sets of data show that there are significant differences in the photochemistry of ChlF and PSII. Mutation of residues that would disrupt the donor side primary electron transfer pathway in PSII do not inhibit the production of Chl f, while alteration of the putative ChlZ, P680 and QA binding sites rendered ChlF non-functional. Together with previously published transient EPR and flash photolysis data, the ODMR data show that in untreated ChlF samples, the triplet state of P680 formed by intersystem crossing is the primary species generated by light excitation. This is in contrast to PSII, in which 3P680 is only formed by charge recombination when the quinone acceptors are removed or chemically reduced. The triplet states of a carotenoid (3Car) and a small amount of 3Chl f are also observed by ODMR. The polarization pattern of 3Car is consistent with its formation by triplet energy transfer from ChlZ if the carotenoid molecule is rotated by 15° about its long axis compared to the orientation in PSII. It is proposed that the singlet oxygen formed by the interaction between molecular oxygen and 3P680 might be involved in the oxidation of Chl a to Chl f.
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Affiliation(s)
- Alessandro Agostini
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131, Padova, Italy; Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, 16802, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, 16802, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, 16802, USA; Department of Chemistry, The Pennsylvania State University, University Park, 16802, USA
| | - Art van der Est
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock, Way, St. Catharines, ON L2S 3A1, Canada.
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131, Padova, Italy.
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Bhattacharjee S, Neese F, Pantazis DA. Triplet states in the reaction center of Photosystem II. Chem Sci 2023; 14:9503-9516. [PMID: 37712047 PMCID: PMC10498673 DOI: 10.1039/d3sc02985a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 08/16/2023] [Indexed: 09/16/2023] Open
Abstract
In oxygenic photosynthesis sunlight is harvested and funneled as excitation energy into the reaction center (RC) of Photosystem II (PSII), the site of primary charge separation that initiates the photosynthetic electron transfer chain. The chlorophyll ChlD1 pigment of the RC is the primary electron donor, forming a charge-separated radical pair with the vicinal pheophytin PheoD1 (ChlD1+PheoD1-). To avert charge recombination, the electron is further transferred to plastoquinone QA, whereas the hole relaxes to a central pair of chlorophylls (PD1PD2), subsequently driving water oxidation. Spin-triplet states can form within the RC when forward electron transfer is inhibited or back reactions are favored. This can lead to formation of singlet dioxygen, with potential deleterious effects. Here we investigate the nature and properties of triplet states within the PSII RC using a multiscale quantum-mechanics/molecular-mechanics (QM/MM) approach. The low-energy spectrum of excited singlet and triplet states, of both local and charge-transfer nature, is compared using range-separated time-dependent density functional theory (TD-DFT). We further compute electron paramagnetic resonance properties (zero-field splitting parameters and hyperfine coupling constants) of relaxed triplet states and compare them with available experimental data. Moreover, the electrostatic modulation of excited state energetics and redox properties of RC pigments by the semiquinone QA- is described. The results provide a detailed electronic-level understanding of triplet states within the PSII RC and form a refined basis for discussing primary and secondary electron transfer, charge recombination pathways, and possible photoprotection mechanisms in PSII.
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Affiliation(s)
- Sinjini Bhattacharjee
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
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Mattila H, Mishra S, Tyystjärvi T, Tyystjärvi E. Singlet oxygen production by photosystem II is caused by misses of the oxygen evolving complex. THE NEW PHYTOLOGIST 2023; 237:113-125. [PMID: 36161283 PMCID: PMC10092662 DOI: 10.1111/nph.18514] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/10/2022] [Indexed: 06/12/2023]
Abstract
Singlet oxygen (1 O2 ) is a harmful species that functions also as a signaling molecule. In chloroplasts, 1 O2 is produced via charge recombination reactions in photosystem II, but which recombination pathway(s) produce triplet Chl and 1 O2 remains open. Furthermore, the role of 1 O2 in photoinhibition is not clear. We compared temperature dependences of 1 O2 production, photoinhibition, and recombination pathways. 1 O2 production by pumpkin thylakoids increased from -2 to +35°C, ruling out recombination of the primary charge pair as a main contributor. S2 QA - or S2 QB - recombination pathways, in turn, had too steep temperature dependences. Instead, the temperature dependence of 1 O2 production matched that of misses (failures of the oxygen (O2 ) evolving complex to advance an S-state). Photoinhibition in vitro and in vivo (also in Synechocystis), and in the presence or absence of O2 , had the same temperature dependence, but ultraviolet (UV)-radiation-caused photoinhibition showed a weaker temperature response. We suggest that the miss-associated recombination of P680 + QA - is the main producer of 1 O2 . Our results indicate three parallel photoinhibition mechanisms. The manganese mechanism dominates in UV radiation but also functions in white light. Mechanisms that depend on light absorption by Chls, having 1 O2 or long-lived P680 + as damaging agents, dominate in red light.
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Affiliation(s)
- Heta Mattila
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuFI‐20014TurkuFinland
| | - Sujata Mishra
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuFI‐20014TurkuFinland
| | - Taina Tyystjärvi
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuFI‐20014TurkuFinland
| | - Esa Tyystjärvi
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuFI‐20014TurkuFinland
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Casazza AP, Lombardi A, Menin B, Santabarbara S. Temperature-induced zeaxanthin overproduction in Synechococcus elongatus PCC 7942. Photochem Photobiol Sci 2022; 22:783-794. [PMID: 36536270 DOI: 10.1007/s43630-022-00352-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022]
Abstract
The exogenous crtZ gene from Brevundimonas sp. SD212, coding for a 3,3' β-car hydroxylase, was expressed in Synechococcus elongatus PCC 7942 under the control of a temperature-inducible promoter in an attempt to engineer the carotenoid metabolic pathway, to increase the content of zeaxanthin and its further hydroxylated derivatives caloxanthin and nostoxanthin. These molecules are of particular interest due to their renowned antioxidant properties. Cultivation of the engineered strain S7942Z-Ti at 35 °C, a temperature which is well tolerated by the wild-type strain and at which the inducible expression system is activated, led to a significant redistribution of the relative carotenoid content. β-Carotene decreased to about 10% of the pool that is an excess of a threefold decrease with respect to the control, and concomitantly, zeaxanthin became the dominant carotenoid accounting for about half of the pool. As a consequence, zeaxanthin and its derivatives caloxanthin and nostoxanthin collectively accounted for about 90% of the accumulated carotenoids. Yet, upon induction of CrtZ expression at 35 °C the S7942Z-Ti strain displayed a substantial growth impairment accompanied, initially, by a relative loss of carotenoids and successively by the appearance of chlorophyll degradation products which can be interpreted as markers of cellular stress. These observations suggest a limit to the exploitation of Synechococcus elongatus PCC 7942 for biotechnological purposes aimed at increasing the production of hydroxylated carotenoids.
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Affiliation(s)
- Anna Paola Casazza
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale Delle Ricerche, Via Bassini 15a, 20133, Milan, Italy.
| | - Alessandro Lombardi
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale Delle Ricerche, Via Bassini 15a, 20133, Milan, Italy
| | - Barbara Menin
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale Delle Ricerche, Via Bassini 15a, 20133, Milan, Italy
| | - Stefano Santabarbara
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale Delle Ricerche, Via Bassini 15a, 20133, Milan, Italy.
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Kandrashkin YE, van der Est A. A two-site triplet exciton hopping model: Application to 3P 700. J Chem Phys 2022; 157:224109. [PMID: 36546793 DOI: 10.1063/5.0132157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A model is presented describing the effect on spin-polarized transient EPR signals caused by incoherent state hopping between two sites. It is shown that the size of the spin state space can be reduced by half to the subspace described by the site-average Hamiltonian and that the dynamics of the system results in a redistribution of the population between its eigenstates. Analytical expressions for the rates of population redistribution and the line shape are derived for the general case in which the back-and-forth rates are unequal. The EPR signals calculated using these expressions are in very good agreement with those obtained by direct numerical solution of the density matrix rate equations. The model is then used to investigate the influence of exciton hopping on triplet state transient EPR spectra. Using the triplet state of the primary donor of Photosystem I as an example, it is shown that the influence of unequal hopping rates becomes more pronounced in the spectrum at longer delay times after the laser flash.
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Affiliation(s)
- Yuri E Kandrashkin
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of RAS, Sibirsky Tract 10/7, Kazan 420029, Russia
| | - Art van der Est
- Department of Chemistry, Brock University, St. Catharines, Ontario L2S 3A1, Canada
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Mattila H, Tyystjärvi E. Light-induced damage to photosystem II at a very low temperature (195 K) depends on singlet oxygen. PHYSIOLOGIA PLANTARUM 2022; 174:e13824. [PMID: 36377045 PMCID: PMC10099935 DOI: 10.1111/ppl.13824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/26/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Photosynthetic organisms, like evergreen plants, may encounter strong light at low temperatures. Light, despite being the energy source of photosynthesis, irreversibly damages photosystem II (PSII). We illuminated plant thylakoid membranes and intact cyanobacterial cells at -78.5°C and assayed PSII activity with oxygen evolution or chlorophyll fluorescence, after thawing the sample. Both UV radiation and visible light damaged PSII of pumpkin (Cucurbita maxima) thylakoids at -78.5°C, but visible-light-induced photoinhibition at -78.5°C, unlike at +20°C, proceeded only in the presence of oxygen. A strong magnetic field that would decrease triplet chlorophyll formation by recombination of the primary radical pair slowed down photoinhibition at -78.5°C, suggesting that singlet oxygen produced via recombination of the primary pair is a major contributor to photoinhibition at -78.5°C. However, a magnetic field did not affect singlet oxygen production at +25°C. Thylakoids of winter leaves of an evergreen plant, Bergenia, were less susceptible to photoinhibition both at -78.5°C and +20°C, contained high amounts of carotenoids and produced little singlet oxygen (measured at +20°C), compared to thylakoids of summer leaves. In contrast, high carotenoid amount and low singlet oxygen yield did not protect a Synechocystis mutant from photoinhibition at -78.5°C. Thylakoids isolated from Arabidopsis thaliana grown under high light, which reduces PSII antenna size, were more resistant than control plants against photoinhibition at -78.5°C but not at +20°C, although carotenoid amounts were similar. The results indicate that visible-light-induced photoinhibition at -78.5°C depends on singlet oxygen, whereas photoinhibition at +20°C is largely independent of oxygen.
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Affiliation(s)
- Heta Mattila
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuTurkuFinland
| | - Esa Tyystjärvi
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuTurkuFinland
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Modulations in Chlorophyll a Fluorescence Based on Intensity and Spectral Variations of Light. Int J Mol Sci 2022; 23:ijms23105599. [PMID: 35628428 PMCID: PMC9146714 DOI: 10.3390/ijms23105599] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/11/2022] [Accepted: 05/12/2022] [Indexed: 01/03/2023] Open
Abstract
Photosynthetic efficiency is significantly affected by both qualitative and quantitative changes during light exposure. The properties of light have a profound effect on electron transport and energy absorption in photochemical reactions. In addition, fluctuations in light intensity and variations in the spectrum can lead to a decrease in photosystem II efficiency. These features necessitate the use of a simple and suitable tool called chlorophyll a fluorescence to study photosynthetic reactions as a function of the aforementioned variables. This research implies that chlorophyll a fluorescence data can be used to determine precise light conditions that help photoautotrophic organisms optimally function.
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11
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Niklas J, Agostini A, Carbonera D, Di Valentin M, Lubitz W. Primary donor triplet states of Photosystem I and II studied by Q-band pulse ENDOR spectroscopy. PHOTOSYNTHESIS RESEARCH 2022; 152:213-234. [PMID: 35290567 PMCID: PMC9424170 DOI: 10.1007/s11120-022-00905-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/14/2022] [Indexed: 05/05/2023]
Abstract
The photoexcited triplet state of the "primary donors" in the two photosystems of oxygenic photosynthesis has been investigated by means of electron-nuclear double resonance (ENDOR) at Q-band (34 GHz). The data obtained represent the first set of 1H hyperfine coupling tensors of the 3P700 triplet state in PSI and expand the existing data set for 3P680. We achieved an extensive assignment of the observed electron-nuclear hyperfine coupling constants (hfcs) corresponding to the methine α-protons and the methyl group β-protons of the chlorophyll (Chl) macrocycle. The data clearly confirm that in both photosystems the primary donor triplet is located on one specific monomeric Chl at cryogenic temperature. In comparison to previous transient ENDOR and pulse ENDOR experiments at standard X-band (9-10 GHz), the pulse Q-band ENDOR spectra demonstrate both improved signal-to-noise ratio and increased resolution. The observed ENDOR spectra for 3P700 and 3P680 differ in terms of the intensity loss of lines from specific methyl group protons, which is explained by hindered methyl group rotation produced by binding site effects. Contact analysis of the methyl groups in the PSI crystal structure in combination with the ENDOR analysis of 3P700 suggests that the triplet is located on the Chl a' (PA) in PSI. The results also provide additional evidence for the localization of 3P680 on the accessory ChlD1 in PSII.
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Affiliation(s)
- Jens Niklas
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany.
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave., Lemont, IL, 60439, USA.
| | - Alessandro Agostini
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy
- Biology Centre, Institute of Plant Molecular Biology, Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Marilena Di Valentin
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy.
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany.
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Violaxanthin and Zeaxanthin May Replace Lutein at the L1 Site of LHCII, Conserving the Interactions with Surrounding Chlorophylls and the Capability of Triplet-Triplet Energy Transfer. Int J Mol Sci 2022; 23:ijms23094812. [PMID: 35563202 PMCID: PMC9105099 DOI: 10.3390/ijms23094812] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/24/2022] [Accepted: 04/25/2022] [Indexed: 01/27/2023] Open
Abstract
Carotenoids represent the first line of defence of photosystems against singlet oxygen (1O2) toxicity, because of their capacity to quench the chlorophyll triplet state (3Chl) through a physical mechanism based on the transfer of triplet excitation (triplet-triplet energy transfer, TTET). In previous works, we showed that the antenna LHCII is characterised by a robust photoprotective mechanism, able to adapt to the removal of individual chlorophylls while maintaining a remarkable capacity for 3Chl quenching. In this work, we investigated the effects on this quenching induced in LHCII by the replacement of the lutein bound at the L1 site with violaxanthin and zeaxanthin. We studied LHCII isolated from the Arabidopsis thaliana mutants lut2-in which lutein is replaced by violaxanthin-and lut2 npq2, in which all xanthophylls are replaced constitutively by zeaxanthin. We characterised the photophysics of these systems via optically detected magnetic resonance (ODMR) and time-resolved electron paramagnetic resonance (TR-EPR). We concluded that, in LHCII, lutein-binding sites have conserved characteristics, and ensure efficient TTET regardless of the identity of the carotenoid accommodated.
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Zavafer A, Mancilla C. Concepts of photochemical damage of Photosystem II and the role of excessive excitation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C: PHOTOCHEMISTRY REVIEWS 2021. [DOI: 10.1016/j.jphotochemrev.2021.100421] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Agostini A, Bortolus M, Ferlez B, Walters K, Golbeck JH, van der Est A, Carbonera D. Differential sensitivity to oxygen among the bacteriochlorophylls g in the type-I reaction centers of Heliobacterium modesticaldum. Photochem Photobiol Sci 2021; 20:747-759. [PMID: 34018156 DOI: 10.1007/s43630-021-00049-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/28/2021] [Indexed: 11/27/2022]
Abstract
The type-I, homodimeric photosynthetic reaction center (RC) of Heliobacteria (HbRC) is the only known RC in which bacteriochlorophyll g (BChl g) is found. It is also simpler than other RCs, having the smallest number of protein subunits and bound chromophores of any type-I RC. In the presence of oxygen, BChl g isomerizes to 81-hydroxychlorophyll aF (Chl aF). This naturally occurring process provides a way of altering the chlorophylls and studying the effect of these changes on energy and electron transfer. Transient absorbance difference spectroscopy reveals that triplet-state formation occurs in the antenna chlorophylls of HbRCs but does not provide site-specific information. Here, we report on an extended optically detected magnetic resonance (ODMR) study of the antenna triplet states in HbRCs with differing levels of conversion of BChl g to Chl aF. The data reveal pools of BChl g molecules with different triplet zero-field splitting parameters and different susceptibilities to chemical oxidation. By relating the detailed spectroscopic characteristics derived from the ODMR data to the recently solved crystallographic structure, we have tentatively identified BChl g molecules in which the probability of triplet formation is high and sites at which BChl g conversion is more likely, providing useful information about the fate of the excitation in the complex.
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Affiliation(s)
- Alessandro Agostini
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131, Padua, Italy.,Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branisovska 31, 37005, České Budějovice, Czechia
| | - Marco Bortolus
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131, Padua, Italy
| | - Bryan Ferlez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.,Department of Biochemistry and Molecular Biology and MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - Karim Walters
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Art van der Est
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock, Way, Saint Catharines, ON, L2S 3A1, Canada.
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131, Padua, Italy.
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15
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Giovagnetti V, Ruban AV. The mechanism of regulation of photosystem I cross-section in the pennate diatom Phaeodactylum tricornutum. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:561-575. [PMID: 33068431 DOI: 10.1093/jxb/eraa478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
Photosystems possess distinct fluorescence emissions at low (77K) temperature. PSI emits in the long-wavelength region at ~710-740 nm. In diatoms, a successful clade of marine primary producers, the contribution of PSI-associated emission (710-717 nm) has been shown to be relatively small. However, in the pennate diatom Phaeodactylum tricornutum, the source of the long-wavelength emission at ~710 nm (F710) remains controversial. Here, we addressed the origin and modulation of F710 fluorescence in this alga grown under continuous and intermittent light. The latter condition led to a strong enhancement in F710. Biochemical and spectral properties of the photosynthetic complexes isolated from thylakoid membranes were investigated for both culture conditions. F710 emission appeared to be associated with PSI regardless of light acclimation. To further assess whether PSII could also contribute to this emission, we decreased the concentration of PSII reaction centres and core antenna by growing cells with lincomycin, a chloroplast protein synthesis inhibitor. The treatment did not diminish F710 fluorescence. Our data suggest that F710 emission originates from PSI under the conditions tested and is enhanced in intermittent light-grown cells due to increased energy flow from the FCP antenna to PSI.
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Affiliation(s)
- Vasco Giovagnetti
- Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Alexander V Ruban
- Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
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16
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Khorobrykh S, Havurinne V, Mattila H, Tyystjärvi E. Oxygen and ROS in Photosynthesis. PLANTS (BASEL, SWITZERLAND) 2020; 9:E91. [PMID: 31936893 PMCID: PMC7020446 DOI: 10.3390/plants9010091] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/29/2019] [Accepted: 01/02/2020] [Indexed: 12/14/2022]
Abstract
Oxygen is a natural acceptor of electrons in the respiratory pathway of aerobic organisms and in many other biochemical reactions. Aerobic metabolism is always associated with the formation of reactive oxygen species (ROS). ROS may damage biomolecules but are also involved in regulatory functions of photosynthetic organisms. This review presents the main properties of ROS, the formation of ROS in the photosynthetic electron transport chain and in the stroma of chloroplasts, and ROS scavenging systems of thylakoid membrane and stroma. Effects of ROS on the photosynthetic apparatus and their roles in redox signaling are discussed.
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Affiliation(s)
| | | | | | - Esa Tyystjärvi
- Department of Biochemistry/Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland or (S.K.); (V.H.); (H.M.)
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17
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Dogra V, Duan J, Lee KP, Kim C. Impaired PSII proteostasis triggers a UPR-like response in the var2 mutant of Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3075-3088. [PMID: 30989223 PMCID: PMC6598079 DOI: 10.1093/jxb/erz151] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/25/2019] [Indexed: 05/18/2023]
Abstract
Cellular protein homeostasis (proteostasis) is maintained through the balance between de novo synthesis and proteolysis. The unfolded/misfolded protein response (UPR) that is triggered by stressed endoplasmic reticulum (ER) also plays an important role in proteostasis in both plants and animals. Although ER-triggered UPR has been extensively studied in plants, the molecular mechanisms underlying mitochondrial and chloroplastic UPRs are largely uncharacterized despite the fact that these organelles are sites of production of harmful reactive oxygen species (ROS), which damage proteins. In this study, we demonstrate that chloroplasts of the Arabidopsis yellow leaf variegation 2 (var2) mutant, which lacks the metalloprotease FtsH2, accumulate damaged chloroplast proteins and trigger a UPR-like response, namely the accumulation of a suite of chloroplast proteins involved in protein quality control (PQC). These PQC proteins include heat-shock proteins, chaperones, proteases, and ROS detoxifiers. Given that FtsH2 functions primarily in photosystem II proteostasis, the accumulation of PQC-related proteins may balance the FtsH2 deficiency. Moreover, the apparent up-regulation of the cognate transcripts indicates that the accumulation of PQC-related proteins in var2 is probably mediated by retrograde signaling, indicating the occurrence of a UPR-like response in var2.
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Affiliation(s)
- Vivek Dogra
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jianli Duan
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Keun Pyo Lee
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- Correspondence:
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18
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Valentini A, Nucci M, Frutos LM, Marazzi M. Photosensitized Retinal Isomerization in Rhodopsin Mediated by a Triplet State. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Alessio Valentini
- Departamento de Química Analítica, Química Física e Ingeniería Química, Unidad de Química FísicaUniversidad de Alcalá Ctra. Madrid-Barcelona Km. 33,600 E-28871 Alcalá de Henares, Madrid Spain
- Department of Biotechnology, Chemistry and PharmacyUniversity of Siena via A. Moro 2 53100 Siena Italy
- Theoretical Physical Chemistry, Research Unit MolSysUniversité de Liège Allée du 6 Aôut, 11 4000 Liège Belgium
| | - Martina Nucci
- Departamento de Química Analítica, Química Física e Ingeniería Química, Unidad de Química FísicaUniversidad de Alcalá Ctra. Madrid-Barcelona Km. 33,600 E-28871 Alcalá de Henares, Madrid Spain
| | - Luis Manuel Frutos
- Departamento de Química Analítica, Química Física e Ingeniería Química, Unidad de Química FísicaUniversidad de Alcalá Ctra. Madrid-Barcelona Km. 33,600 E-28871 Alcalá de Henares, Madrid Spain
- Instituto de Investigación Química “Andrés M. del Río” (IQAR)Universidad de Alcalá E-28871 Alcalá de Henares, Madrid Spain
| | - Marco Marazzi
- Departamento de Química Analítica, Química Física e Ingeniería Química, Unidad de Química FísicaUniversidad de Alcalá Ctra. Madrid-Barcelona Km. 33,600 E-28871 Alcalá de Henares, Madrid Spain
- Instituto de Investigación Química “Andrés M. del Río” (IQAR)Universidad de Alcalá E-28871 Alcalá de Henares, Madrid Spain
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19
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Dogra V, Kim C. Singlet Oxygen Metabolism: From Genesis to Signaling. FRONTIERS IN PLANT SCIENCE 2019; 10:1640. [PMID: 31969891 PMCID: PMC6960194 DOI: 10.3389/fpls.2019.01640] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 11/21/2019] [Indexed: 05/03/2023]
Abstract
Singlet oxygen (1O2) is an excited state of molecular oxygen with an electron spin shift in the molecular orbitals, which is extremely unstable and highly reactive. In plants, 1O2 is primarily generated as a byproduct of photosynthesis in the photosystem II reaction center (PSII RC) and the light-harvesting antenna complex (LHC) in the grana core (GC). This occurs upon the absorption of light energy when the excited chlorophyll molecules in the PSII transfer the excess energy to molecular oxygen, thereby generating 1O2. As a potent oxidant, 1O2 promotes oxidative damage. However, at sub-lethal levels, it initiates chloroplast-to-nucleus retrograde signaling to contribute to plant stress responses, including acclimation and cell death. The thylakoid membranes comprise two spatially separated 1O2 sensors: β-carotene localized in the PSII RC in the GC and the nuclear-encoded chloroplast protein EXECUTER1 (EX1) residing in the non-appressed grana margin (GM). Finding EX1 in the GM suggests the existence of an additional source of 1O2 in the GM and the presence of two distinct 1O2-signaling pathways. In this review, we mainly discuss the genesis and impact of 1O2 in plant physiology.
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20
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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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21
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Dogra V, Rochaix JD, Kim C. Singlet oxygen-triggered chloroplast-to-nucleus retrograde signalling pathways: An emerging perspective. PLANT, CELL & ENVIRONMENT 2018; 41:1727-1738. [PMID: 29749057 DOI: 10.1111/pce.13332] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 05/19/2023]
Abstract
Singlet oxygen (1 O2 ) is a prime cause of photo-damage of the photosynthetic apparatus. The chlorophyll molecules in the photosystem II reaction center and in the light-harvesting antenna complex are major sources of 1 O2 generation. It has been thought that the generation of 1 O2 mainly takes place in the appressed regions of the thylakoid membranes, namely, the grana core, where most of the active photosystem II complexes are localized. Apart from being a toxic molecule, new evidence suggests that 1 O2 significantly contributes to chloroplast-to-nucleus retrograde signalling that primes acclimation and cell death responses. Interestingly, recent studies reveal that chloroplasts operate two distinct 1 O2 -triggered retrograde signalling pathways in which β-carotene and a nuclear-encoded chloroplast protein EXECUTER1 play essential roles as signalling mediators. The coexistence of these mediators raises several questions: their crosstalk, source(s) of 1 O2 , downstream signalling components, and the perception and reaction mechanism of these mediators towards 1 O2 . In this review, we mainly discuss the molecular genetic basis of the mode of action of these two putative 1 O2 sensors and their corresponding retrograde signalling pathways. In addition, we also propose the possible existence of an alternative source of 1 O2 , which is spatially and functionally separated from the grana core.
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Affiliation(s)
- Vivek Dogra
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Jean-David Rochaix
- Department of Molecular Biology and Plant Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
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22
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Agostini A, Palm DM, Paulsen H, Carbonera D. Optically Detected Magnetic Resonance of Chlorophyll Triplet States in Water-Soluble Chlorophyll Proteins from Lepidium virginicum: Evidence for Excitonic Interaction among the Four Pigments. J Phys Chem B 2018; 122:6156-6163. [DOI: 10.1021/acs.jpcb.8b01906] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Alessandro Agostini
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
- Institute of Molecular Physiology, Johannes-Gutenberg University Mainz, Johannes-von-Müller-Weg 6, 55128 Mainz, Germany
| | - Daniel M. Palm
- Institute of Molecular Physiology, Johannes-Gutenberg University Mainz, Johannes-von-Müller-Weg 6, 55128 Mainz, Germany
| | - Harald Paulsen
- Institute of Molecular Physiology, Johannes-Gutenberg University Mainz, Johannes-von-Müller-Weg 6, 55128 Mainz, Germany
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
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23
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High photochemical trapping efficiency in Photosystem I from the red clade algae Chromera velia and Phaeodactylum tricornutum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:56-63. [DOI: 10.1016/j.bbabio.2016.10.002] [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: 11/23/2022]
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24
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Wobbe L, Bassi R, Kruse O. Multi-Level Light Capture Control in Plants and Green Algae. TRENDS IN PLANT SCIENCE 2016; 21:55-68. [PMID: 26545578 DOI: 10.1016/j.tplants.2015.10.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 09/16/2015] [Accepted: 10/05/2015] [Indexed: 05/02/2023]
Abstract
Life on Earth relies on photosynthesis, and the ongoing depletion of fossil carbon fuels has renewed interest in phototrophic light-energy conversion processes as a blueprint for the conversion of atmospheric CO2 into various organic compounds. Light-harvesting systems have evolved in plants and green algae, which are adapted to the light intensity and spectral composition encountered in their habitats. These organisms are constantly challenged by a fluctuating light supply and other environmental cues affecting photosynthetic performance. Excess light can be especially harmful, but plants and microalgae are equipped with different acclimation mechanisms to control the processing of sunlight absorbed at both photosystems. We summarize the current knowledge and discuss the potential for optimization of phototrophic light-energy conversion.
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Affiliation(s)
- Lutz Wobbe
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615, Bielefeld, Germany
| | - Roberto Bassi
- Universita degli Studi di Verona, Department of Biotechnology, Strada Le Grazie 15, 37134 Verona, Italy
| | - Olaf Kruse
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615, Bielefeld, Germany.
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Caffarri S, Tibiletti T, Jennings RC, Santabarbara S. A comparison between plant photosystem I and photosystem II architecture and functioning. Curr Protein Pept Sci 2015; 15:296-331. [PMID: 24678674 PMCID: PMC4030627 DOI: 10.2174/1389203715666140327102218] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 11/22/2013] [Accepted: 03/16/2014] [Indexed: 01/31/2023]
Abstract
Oxygenic photosynthesis is indispensable both for the development and maintenance of life on earth by converting
light energy into chemical energy and by producing molecular oxygen and consuming carbon dioxide. This latter
process has been responsible for reducing the CO2 from its very high levels in the primitive atmosphere to the present low
levels and thus reducing global temperatures to levels conducive to the development of life. Photosystem I and photosystem
II are the two multi-protein complexes that contain the pigments necessary to harvest photons and use light energy to
catalyse the primary photosynthetic endergonic reactions producing high energy compounds. Both photosystems are
highly organised membrane supercomplexes composed of a core complex, containing the reaction centre where electron
transport is initiated, and of a peripheral antenna system, which is important for light harvesting and photosynthetic activity
regulation. If on the one hand both the chemical reactions catalysed by the two photosystems and their detailed structure
are different, on the other hand they share many similarities. In this review we discuss and compare various aspects of
the organisation, functioning and regulation of plant photosystems by comparing them for similarities and differences as
obtained by structural, biochemical and spectroscopic investigations.
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Affiliation(s)
| | | | | | - Stefano Santabarbara
- Laboratoire de Génétique et de Biophysique des Plantes (LGBP), Aix-Marseille Université, Faculté des Sciences de Luminy, 163 Avenue de Luminy, 13009, Marseille, France.
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26
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Khorobrykh SA, Karonen M, Tyystjärvi E. Experimental evidence suggesting that H2O2 is produced within the thylakoid membrane in a reaction between plastoquinol and singlet oxygen. FEBS Lett 2015; 589:779-86. [PMID: 25701589 DOI: 10.1016/j.febslet.2015.02.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/30/2015] [Accepted: 02/10/2015] [Indexed: 10/24/2022]
Abstract
Plastoquinol (PQH2-9) and plastoquinone (PQ-9) mediate photosynthetic electron transfer. We isolated PQH2-9 from thylakoid membranes, purified it with HPLC, subjected the purified PQH2-9 to singlet oxygen ((1)O2) and analyzed the products. The main reaction of (1)O2 with PQH2-9 in methanol was found to result in formation of PQ-9 and H2O2, and the amount of H2O2 produced was essentially the same as the amount of oxidized PQH2-9. Formation of H2O2 in the reaction between (1)O2 and PQH2-9 may be an important source of H2O2 within the lipophilic thylakoid membrane.
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Affiliation(s)
- Sergey A Khorobrykh
- Department of Biochemistry/Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Maarit Karonen
- Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, FI-20014 Turku, Finland
| | - Esa Tyystjärvi
- Department of Biochemistry/Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
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27
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Santabarbara S, Agostini A, Casazza AP, Zucchelli G, Carbonera D. Carotenoid triplet states in photosystem II: coupling with low-energy states of the core complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:262-275. [PMID: 25481107 DOI: 10.1016/j.bbabio.2014.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/19/2014] [Accepted: 11/21/2014] [Indexed: 11/28/2022]
Abstract
The photo-excited triplet states of carotenoids, sensitised by triplet-triplet energy transfer from the chlorophyll triplet states, have been investigated in the isolated Photosystem II (PSII) core complex and PSII-LHCII (Light Harvesting Complex II) supercomplex by Optically Detected Magnetic Resonance techniques, using both fluorescence (FDMR) and absorption (ADMR) detection. The absence of Photosystem I allows us to reach the full assignment of the carotenoid triplet states populated in PSII under steady state illumination at low temperature. Five carotenoid triplet ((3)Car) populations were identified in PSII-LHCII, and four in the PSII core complex. Thus, four (3)Car populations are attributed to β-carotene molecules bound to the core complex. All of them show associated fluorescence emission maxima which are relatively red-shifted with respect to the bulk emission of both the PSII-LHCII and the isolated core complexes. In particular the two populations characterised by Zero Field Splitting parameters |D|=0.0370-0.0373 cm(-1)/|E|=0.00373-0.00375 cm(-1) and |D|=0.0381-0.0385 cm(-1)/|E|=0.00393-0.00389 cm(-1), are coupled by singlet energy transfer with chlorophylls which have a red-shifted emission peaking at 705 nm. This observation supports previous suggestions that pointed towards the presence of long-wavelength chlorophyll spectral forms in the PSII core complex. The fifth (3)Car component is observed only in the PSII-LHCII supercomplex and is then assigned to the peripheral light harvesting system.
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Affiliation(s)
- Stefano Santabarbara
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via Celoria 26, 20133 Milan, Italy.
| | - Alessandro Agostini
- Department of Chemical Sciences, Università di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Anna Paola Casazza
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133 Milano, Italy
| | - Giuseppe Zucchelli
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via Celoria 26, 20133 Milan, Italy
| | - Donatella Carbonera
- Department of Chemical Sciences, Università di Padova, Via Marzolo 1, 35131 Padova, Italy.
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Porcar-Castell A, Tyystjärvi E, Atherton J, van der Tol C, Flexas J, Pfündel EE, Moreno J, Frankenberg C, Berry JA. Linking chlorophyll a fluorescence to photosynthesis for remote sensing applications: mechanisms and challenges. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4065-95. [PMID: 24868038 DOI: 10.1093/jxb/eru191] [Citation(s) in RCA: 283] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Chlorophyll a fluorescence (ChlF) has been used for decades to study the organization, functioning, and physiology of photosynthesis at the leaf and subcellular levels. ChlF is now measurable from remote sensing platforms. This provides a new optical means to track photosynthesis and gross primary productivity of terrestrial ecosystems. Importantly, the spatiotemporal and methodological context of the new applications is dramatically different compared with most of the available ChlF literature, which raises a number of important considerations. Although we have a good mechanistic understanding of the processes that control the ChlF signal over the short term, the seasonal link between ChlF and photosynthesis remains obscure. Additionally, while the current understanding of in vivo ChlF is based on pulse amplitude-modulated (PAM) measurements, remote sensing applications are based on the measurement of the passive solar-induced chlorophyll fluorescence (SIF), which entails important differences and new challenges that remain to be solved. In this review we introduce and revisit the physical, physiological, and methodological factors that control the leaf-level ChlF signal in the context of the new remote sensing applications. Specifically, we present the basis of photosynthetic acclimation and its optical signals, we introduce the physical and physiological basis of ChlF from the molecular to the leaf level and beyond, and we introduce and compare PAM and SIF methodology. Finally, we evaluate and identify the challenges that still remain to be answered in order to consolidate our mechanistic understanding of the remotely sensed SIF signal.
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Affiliation(s)
- Albert Porcar-Castell
- Department of Forest Sciences, University of Helsinki, PO Box 27, 00014 Helsinki, Finland
| | - Esa Tyystjärvi
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Jon Atherton
- Department of Forest Sciences, University of Helsinki, PO Box 27, 00014 Helsinki, Finland
| | | | - Jaume Flexas
- Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Ctra. de Valldemossa Km. 7.5, 07122 Palma, Spain
| | | | - Jose Moreno
- Department of Earth Physics and Thermodynamics, Faculty of Physics, University of Valencia, C/ Dr. Moliner, 50, 46100 Burjassot, Valencia, Spain
| | - Christian Frankenberg
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Joseph A Berry
- Department of Global Ecology, Carnegie Institution of Washington, Stanford, CA 94305, USA
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Rizzo F, Zucchelli G, Jennings R, Santabarbara S. Wavelength dependence of the fluorescence emission under conditions of open and closed Photosystem II reaction centres in the green alga Chlorella sorokiniana. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:726-33. [PMID: 24561096 DOI: 10.1016/j.bbabio.2014.02.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 11/29/2022]
Abstract
The fluorescence emission characteristics of the photosynthetic apparatus under conditions of open (F0) and closed (FM) Photosystem II reaction centres have been investigated under steady state conditions and by monitoring the decay lifetimes of the excited state, in vivo, in the green alga Chlorella sorokiniana. The results indicate a marked wavelength dependence of the ratio of the variable fluorescence, FV=FM-F0, over FM, a parameter that is often employed to estimate the maximal quantum efficiency of Photosystem II. The maximal value of the FV/FM ratio is observed between 660 and 680nm and the minimal in the 690-730nm region. It is possible to attribute the spectral variation of FV/FM principally to the contribution of Photosystem I fluorescence emission at room temperature. Moreover, the analysis of the excited state lifetime at F0 and FM indicates only a small wavelength dependence of Photosystem II trapping efficiency in vivo.
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Affiliation(s)
- Federico Rizzo
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, via Celoria 26, 20133 Milano, Italy; Dipartimento di Bioscienze, Università di Milano, via Celoria 26, 20133 Milano, Italy
| | - Giuseppe Zucchelli
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, via Celoria 26, 20133 Milano, Italy; Dipartimento di Bioscienze, Università di Milano, via Celoria 26, 20133 Milano, Italy
| | - Robert Jennings
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, via Celoria 26, 20133 Milano, Italy; Dipartimento di Bioscienze, Università di Milano, via Celoria 26, 20133 Milano, Italy
| | - Stefano Santabarbara
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, via Celoria 26, 20133 Milano, Italy; Dipartimento di Bioscienze, Università di Milano, via Celoria 26, 20133 Milano, Italy.
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Isolation and characterization of phytotoxic compounds produced by Streptomyces sp. AMC 23 from red mangrove (Rhizophora mangle). Appl Biochem Biotechnol 2013; 171:1602-16. [PMID: 23979946 DOI: 10.1007/s12010-013-0418-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 07/29/2013] [Indexed: 10/26/2022]
Abstract
Natural products produced by microorganisms have been utilized as sources of new drugs possessing a wide range of agrochemical and pharmacological activities. During our research on Actinomycetes from Brazilian mangroves, the ethyl acetate extract of Streptomyces sp. AMC 23 isolated from the red mangrove (Rhizophora mangle) rhizosphere produced a highly active compound against the microalga Chlorella vulgaris, often used to assess the phytotoxic activity. As a result, the bioassay-guided fractionation led to the isolation of the mixture of the known compounds bafilomycin B1 and bafilomycin B2. The chemical structures of bafilomycin B1 and bafilomycin B2 were established based on their spectroscopic data by infrared (IR), mass spectrometry (MS), (1)H nuclear magnetic resonance (NMR), gradient-enhanced heteronuclear multiple quantum coherence (gHMQC), and gradient-enhanced heteronuclear multiple-bond connectivity (gHMBC) as well as comparison with reference data from the literature. Moreover, it was also possible to identify other bafilomycins using non-chromatographic-dependent techniques (Tandem mass spectrometry). Additionally, this is the first report on the phytotoxic activity of bafilomycin B1.
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Ballottari M, Mozzo M, Girardon J, Hienerwadel R, Bassi R. Chlorophyll triplet quenching and photoprotection in the higher plant monomeric antenna protein Lhcb5. J Phys Chem B 2013; 117:11337-48. [PMID: 23786371 DOI: 10.1021/jp402977y] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In oxygenic photosynthetic organisms, chlorophyll triplets are harmful excited states readily reacting with molecular oxygen to yield the reactive oxygen species (ROS) singlet oxygen. Carotenoids have a photoprotective role in photosynthetic membranes by preventing photoxidative damage through quenching of chlorophyll singlets and triplets. In this work we used mutation analysis to investigate the architecture of chlorophyll triplet quenching sites within Lhcb5, a monomeric antenna protein of Photosystem II. The carotenoid and chlorophyll triplet formation as well as the production of ROS molecules were studied in a family of recombinant Lhcb5 proteins either with WT sequence, mutated into individual chlorophyll binding residues or refolded in vitro to bind different xanthophyll complements. We observed a site-specific effect in the efficiency of chlorophyll-carotenoid triplet-triplet energy transfer. Thus chlorophyll (Chl) 602 and 603 appear to be particularly important for triplet-triplet energy transfer to the xanthophyll bound into site L2. Surprisingly, mutation on Chl 612, the chlorophyll with the lower energy associated and in close contact with lutein in site L1, had no effect on quenching chlorophyll triplet excited states. Finally, we present evidence for an indirect role of neoxanthin in chlorophyll triplet quenching and show that quenching of both singlet and triplet states is necessary for minimizing singlet oxygen formation.
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Affiliation(s)
- Matteo Ballottari
- Dipartimento di Biotecnologie, Università di Verona , Ca' Vignal 1, strada le Grazie 15, I-37134 Verona, Italy
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32
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Delayed fluorescence spectra of intact leaves photoexcited by sunlight measured with a multichannel Fourier-transform chemiluminescence spectrometer. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.04.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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Tyystjärvi E. Photoinhibition of Photosystem II. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 300:243-303. [PMID: 23273864 DOI: 10.1016/b978-0-12-405210-9.00007-2] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Photoinhibition of Photosystem II (PSII) is the light-induced loss of PSII electron-transfer activity. Although photoinhibition has been studied for a long time, there is no consensus about its mechanism. On one hand, production of singlet oxygen ((1)O(2)) by PSII has promoted models in which this reactive oxygen species (ROS) is considered to act as the agent of photoinhibitory damage. These chemistry-based models have often not taken into account the photophysical features of photoinhibition-like light response and action spectrum. On the other hand, models that reproduce these basic photophysical features of the reaction have not considered the importance of data about ROS. In this chapter, it is shown that the evidence behind the chemistry-based models and the photophysically oriented models can be brought together to build a mechanism that confirms with all types of experimental data. A working hypothesis is proposed, starting with inhibition of the manganese complex by light. Inability of the manganese complex to reduce the primary donor promotes recombination between the oxidized primary donor and Q(A), the first stable quinone acceptor of PSII. (1)O(2) production due to this recombination may inhibit protein synthesis or spread the photoinhibitory damage to another PSII center. The production of (1)O(2) is transient because loss of activity of the oxygen-evolving complex induces an increase in the redox potential of Q(A), which lowers (1)O(2) production.
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Affiliation(s)
- Esa Tyystjärvi
- Molecular Plant Biology, Department of Biochemistry and Food Chemistry, University of Turku, Turku, Finland.
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Santabarbara S, Casazza AP, Ali K, Economou CK, Wannathong T, Zito F, Redding KE, Rappaport F, Purton S. The requirement for carotenoids in the assembly and function of the photosynthetic complexes in Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 2013; 161:535-46. [PMID: 23161889 PMCID: PMC3532283 DOI: 10.1104/pp.112.205260] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We have investigated the importance of carotenoids on the accumulation and function of the photosynthetic apparatus using a mutant of the green alga Chlamydomonas reinhardtii lacking carotenoids. The FN68 mutant is deficient in phytoene synthase, the first enzyme of the carotenoid biosynthesis pathway, and therefore is unable to synthesize any carotenes and xanthophylls. We find that FN68 is unable to accumulate the light-harvesting complexes associated with both photosystems as well as the RC subunits of photosystem II. The accumulation of the cytochrome b₆f complex is also strongly reduced to a level approximately 10% that of the wild type. However, the residual fraction of assembled cytochrome b₆f complexes exhibits single-turnover electron transfer kinetics comparable to those observed in the wild-type strain. Surprisingly, photosystem I is assembled to significant levels in the absence of carotenoids in FN68 and possesses functional properties that are very similar to those of the wild-type complex.
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Affiliation(s)
- Stefano Santabarbara
- Institute of Structural and Molecular Biology, University College London, London WC1E 6BT, United Kingdom.
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Carbonera D, Gerotto C, Posocco B, Giacometti GM, Morosinotto T. NPQ activation reduces chlorophyll triplet state formation in the moss Physcomitrella patens. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1608-15. [DOI: 10.1016/j.bbabio.2012.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 05/11/2012] [Accepted: 05/15/2012] [Indexed: 10/28/2022]
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36
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Santabarbara S, Reifschneider K, Jasaitis A, Gu F, Agostini G, Carbonera D, Rappaport F, Redding KE. Interquinone electron transfer in photosystem I as evidenced by altering the hydrogen bond strength to the phylloquinone(s). J Phys Chem B 2010; 114:9300-12. [PMID: 20583790 DOI: 10.1021/jp1038656] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The kinetics of electron transfer from phyllosemiquinone (PhQ(*-)) to the iron sulfur cluster F(X) in Photosystem I (PS I) are described by lifetimes of approximately 20 and approximately 250 ns. These two rates are attributed to reactions involving the quinones bound primarily by the PsaB (PhQ(B)) and PsaA (PhQ(A)) subunits, respectively. The factors leading to a approximately 10-fold difference between the observed lifetimes are not yet clear. The peptide nitrogen of conserved residues PsaA-Leu722 and PsaB-Leu706 is involved in asymmetric hydrogen-bonding to PhQ(A) and PhQ(B), respectively. Upon mutation of these residues in PS I of the green alga, Chlamydomonas reinhardtii , we observe an acceleration of the oxidation kinetics of the PhQ(*-) interacting with the targeted residue: from approximately 255 to approximately 180 ns in PsaA-L722Y/T and from approximately 24 to approximately 10 ns in PsaB-L706Y. The acceleration of the kinetics in the mutants is consistent with a perturbation of the H-bond, destabilizing the PhQ(*-) state, and increasing the driving force of its oxidation. Surprisingly, the relative amplitudes of the phases reflecting PhQ(A)(*-) and PhQ(B)(*-) oxidation were also affected by these mutations: the apparent PhQ(A)(*-)/PhQ(B)(*-) ratio is shifted from 0.65:0.35 in wild-type reaction centers to 0.5:0.5 in PsaA-L722Y/T and to 0.8:0.2 in PsaB-L706Y. The most consistent account for all these observations involves considering reversibility of oxidation of PhQ(A)(*-) and PhQ(B)(*-) by F(X), and asymmetry in the driving forces for these electron transfer reactions, which in turn leads to F(x)-mediated interquinone electron transfer.
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Affiliation(s)
- Stefano Santabarbara
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA.
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Di Valentin M, Ceola S, Agostini G, Telfer A, Barber J, Böhles F, Santabarbara S, Carbonera D. The photo-excited triplet state of chlorophylldin methyl-tetrahydrofuran studied by optically detected magnetic resonance and time-resolved EPR. Mol Phys 2010. [DOI: 10.1080/00268970701627797] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Carbonera D. Optically Detected Magnetic Resonance (ODMR) of photoexcited triplet states. PHOTOSYNTHESIS RESEARCH 2009; 102:403-414. [PMID: 19238576 DOI: 10.1007/s11120-009-9407-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Accepted: 01/15/2009] [Indexed: 05/27/2023]
Abstract
Optically Detected Magnetic Resonance (ODMR) is a double resonance technique which combines optical measurements (fluorescence, phosphorescence, absorption) with electron spin resonance spectroscopy. After the first triplet-state ODMR experiments in zero magnetic field reported in 1968 by Schmidt and van der Waals, the number of double resonance studies on excited triplet states grew rapidly. Photosynthesis has proven to be a fruitful field of application due to the intrinsic possibility of forming photo-induced pigment triplet states in many sites of the photosynthetic apparatus. The basic principles of this technique are described and examples of application in Photosynthesis are reported.
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Affiliation(s)
- Donatella Carbonera
- Dipartimento di Scienze Chimiche, Universitá di Padova, 35131 Padova, Italy.
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van de Poll WH, Buma AGJ. Does ultraviolet radiation affect the xanthophyll cycle in marine phytoplankton? Photochem Photobiol Sci 2009; 8:1295-301. [DOI: 10.1039/b904501e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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