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Zavafer A, Chow WS, Cheah MH. The action spectrum of Photosystem II photoinactivation in visible light. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 152:247-60. [PMID: 26298696 DOI: 10.1016/j.jphotobiol.2015.08.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 07/23/2015] [Accepted: 08/10/2015] [Indexed: 12/25/2022]
Abstract
Photosynthesis is always accompanied by light induced damage to the Photosystem II (PSII) which is compensated by its subsequent repair. Photoinhibition of PSII is a complex process, balancing between photoinactivation, protective and repair mechanisms. Current understanding of photoinactivation is limited with competing hypotheses where the photosensitiser is either photosynthetic pigments or the Mn4CaO5 cluster itself, with little consensus on the mechanisms and consequences of PSII photoinactivation. The mechanism of photoinactivation should be reflected in the action spectrum of PSII photoinactivation, but there is a great diversity of the action spectra reported thus far. The only consensus is that PSII photoinactivation is greatest in the UV region of the electromagnetic spectrum. In this review, the authors revisit the methods, technical constraints and the different action spectra of PSII photoinactivation reported to date and compare them against the diverse mechanisms proposed. Upon critical examination of the reported action spectra, a hybrid mechanism of photoinactivation, sensitised by both photosynthetic pigments and the Mn4CaO5 appears to be the most plausible rationalisation.
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Affiliation(s)
- Alonso Zavafer
- Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra ACT 2601, Australia
| | - Wah Soon Chow
- Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra ACT 2601, Australia
| | - Mun Hon Cheah
- Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra ACT 2601, Australia.
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Goldschmidt-Clermont M, Bassi R. Sharing light between two photosystems: mechanism of state transitions. CURRENT OPINION IN PLANT BIOLOGY 2015; 25:71-8. [PMID: 26002067 DOI: 10.1016/j.pbi.2015.04.009] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 04/17/2015] [Accepted: 04/30/2015] [Indexed: 05/19/2023]
Abstract
In the thylakoid membrane, the two photosystems act in series to promote linear electron flow, with the concomitant production of ATP and reducing equivalents such as NADPH. Photosystem I, which is preferentially activated in far-red light, also energizes cyclic electron flow which generates only ATP. Thus, changes in light quality and cellular metabolic demand require a rapid regulation of the activity of the two photosystems. At low light intensities, this is mediated by state transitions. They allow the dynamic allocation of light harvesting antennae to the two photosystems, regulated through protein phosphorylation by a kinase and phosphatase pair that respond to the redox state of the electron transfer chain. Phosphorylation of the antennae leads to remodeling of the photosynthetic complexes.
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Affiliation(s)
- Michel Goldschmidt-Clermont
- Department of Botany and Plant Biology, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva 4, Switzerland.
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Università degli Studi di Verona, 15, strada Le Grazie, 37134 Verona, Italy
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Grewe S, Ballottari M, Alcocer M, D'Andrea C, Blifernez-Klassen O, Hankamer B, Mussgnug JH, Bassi R, Kruse O. Light-Harvesting Complex Protein LHCBM9 Is Critical for Photosystem II Activity and Hydrogen Production in Chlamydomonas reinhardtii. THE PLANT CELL 2014; 26:1598-1611. [PMID: 24706511 PMCID: PMC4036574 DOI: 10.1105/tpc.114.124198] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Photosynthetic organisms developed multiple strategies for balancing light-harvesting versus intracellular energy utilization to survive ever-changing environmental conditions. The light-harvesting complex (LHC) protein family is of paramount importance for this function and can form light-harvesting pigment protein complexes. In this work, we describe detailed analyses of the photosystem II (PSII) LHC protein LHCBM9 of the microalga Chlamydomonas reinhardtii in terms of expression kinetics, localization, and function. In contrast to most LHC members described before, LHCBM9 expression was determined to be very low during standard cell cultivation but strongly increased as a response to specific stress conditions, e.g., when nutrient availability was limited. LHCBM9 was localized as part of PSII supercomplexes but was not found in association with photosystem I complexes. Knockdown cell lines with 50 to 70% reduced amounts of LHCBM9 showed reduced photosynthetic activity upon illumination and severe perturbation of hydrogen production activity. Functional analysis, performed on isolated PSII supercomplexes and recombinant LHCBM9 proteins, demonstrated that presence of LHCBM9 resulted in faster chlorophyll fluorescence decay and reduced production of singlet oxygen, indicating upgraded photoprotection. We conclude that LHCBM9 has a special role within the family of LHCII proteins and serves an important protective function during stress conditions by promoting efficient light energy dissipation and stabilizing PSII supercomplexes.
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Affiliation(s)
- Sabrina Grewe
- Algae Biotechnology and Bioenergy Group, Department of Biology, Center for Biotechnology, Bielefeld University, D-33615 Bielefeld, Germany
| | - Matteo Ballottari
- Dipartimento di Biotecnologie, Università di Verona, I-37134 Verona, Italy
| | - Marcelo Alcocer
- INF-CNR, Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia, 20133 Milan, Italy
| | - Cosimo D'Andrea
- INF-CNR, Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia, 20133 Milan, Italy
| | - Olga Blifernez-Klassen
- Algae Biotechnology and Bioenergy Group, Department of Biology, Center for Biotechnology, Bielefeld University, D-33615 Bielefeld, Germany
| | - Ben Hankamer
- Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland 4072, Australia
| | - Jan H Mussgnug
- Algae Biotechnology and Bioenergy Group, Department of Biology, Center for Biotechnology, Bielefeld University, D-33615 Bielefeld, Germany
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Università di Verona, I-37134 Verona, Italy
| | - Olaf Kruse
- Algae Biotechnology and Bioenergy Group, Department of Biology, Center for Biotechnology, Bielefeld University, D-33615 Bielefeld, Germany
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Zhang L, Melø TB, Li H, Naqvi KR, Yang C. The inter-monomer interface of the major light-harvesting chlorophyll a/b complexes of photosystem II (LHCII) influences the chlorophyll triplet distribution. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:42-8. [PMID: 24484957 DOI: 10.1016/j.jplph.2013.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 11/16/2013] [Accepted: 11/18/2013] [Indexed: 06/03/2023]
Abstract
Under strong light conditions, long-lived chlorophyll triplets ((3)Chls) are formed, which can sensitize singlet oxygen, a species harmful to the photosynthetic apparatus of plants. Plants have developed multiple photoprotective mechanisms to quench (3)Chl and scavenge singlet oxygen in order to sustain the photosynthetic activities. The lumenal loop of light-harvesting chlorophyll a/b complex of photosystem II (LHCII) plays important roles in regulating the pigment conformation and energy dissipation. In this study, site-directed mutagenesis analysis was applied to investigate triplet-triplet energy transfer and quenching of (3)Chl in LHCII. We mutated the amino acid at site 123 located in this region to Gly, Pro, Gln, Thr and Tyr, respectively, and recorded fluorescence excitation spectra, triplet-minus-singlet (TmS) spectra and kinetics of carotenoid triplet decay for wild type and all the mutants. A red-shift was evident in the TmS spectra of the mutants S123T and S123P, and all of the mutants except S123Y showed a decrease in the triplet energy transfer efficiency. We propose, on the basis of the available structural information, that these phenomena are related to the involvement, due to conformational changes in the lumenal region, of a long-wavelength lutein (Lut2) involved in quenching (3)Chl.
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Affiliation(s)
- Lei Zhang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Thor Bernt Melø
- Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Heng Li
- Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - K Razi Naqvi
- Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
| | - Chunhong Yang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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