1
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Chiariello MG, Zarmiento-Garcia R, Marrink SJ. Martini 3 Coarse-Grained Model for the Cofactors Involved in Photosynthesis. Int J Mol Sci 2024; 25:7947. [PMID: 39063190 PMCID: PMC11277265 DOI: 10.3390/ijms25147947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Revised: 07/15/2024] [Accepted: 07/18/2024] [Indexed: 07/28/2024] Open
Abstract
As a critical step in advancing the simulation of photosynthetic complexes, we present the Martini 3 coarse-grained (CG) models of key cofactors associated with light harvesting (LHCII) proteins and the photosystem II (PSII) core complex. Our work focuses on the parametrization of beta-carotene, plastoquinone/quinol, violaxanthin, lutein, neoxanthin, chlorophyll A, chlorophyll B, and heme. We derived the CG parameters to match the all-atom reference simulations, while structural and thermodynamic properties of the cofactors were compared to experimental values when available. To further assess the reliability of the parameterization, we tested the behavior of these cofactors within their physiological environments, specifically in a lipid bilayer and bound to photosynthetic complexes. The results demonstrate that our CG models maintain the essential features required for realistic simulations. This work lays the groundwork for detailed simulations of the PSII-LHCII super-complex, providing a robust parameter set for future studies.
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Affiliation(s)
| | | | - Siewert-Jan Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands; (M.G.C.); (R.Z.-G.)
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2
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Zhao Y, Deng L, Last RL, Hua W, Liu J. Psb28 protein is indispensable for stable accumulation of PSII core complexes in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024. [PMID: 38796842 DOI: 10.1111/tpj.16844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/24/2024] [Accepted: 05/07/2024] [Indexed: 05/29/2024]
Abstract
Enhancing the efficiency of photosynthesis represents a promising strategy to improve crop yields, with keeping the steady state of PSII being key to determining the photosynthetic performance. However, the mechanisms whereby the stability of PSII is maintained in oxygenic organisms remain to be explored. Here, we report that the Psb28 protein functions in regulating the homeostasis of PSII under different light conditions in Arabidopsis thaliana. The psb28 mutant is much smaller than the wild-type plants under normal growth light, which is due to its significantly reduced PSII activity. Similar defects were seen under low light and became more pronounced under photoinhibitory light. Notably, the amounts of PSII core complexes and core subunits are specifically decreased in psb28, whereas the abundance of other representative components of photosynthetic complexes remains largely unaltered. Although the PSII activity of psb28 was severely reduced when subjected to high light, its recovery from photoinactivation was not affected. By contrast, the degradation of PSII core protein subunits is dramatically accelerated in the presence of lincomycin. These results indicate that psb28 is defective in the photoprotection of PSII, which is consistent with the observation that the overall NPQ is much lower in psb28 compared to the wild type. Moreover, the Psb28 protein is associated with PSII core complexes and interacts mainly with the CP47 subunit of PSII core. Taken together, these findings reveal an important role for Psb28 in the protection and stabilization of PSII core in response to changes in light environments.
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Affiliation(s)
- Yuwei Zhao
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China
- Huazhong Agricultural University, National Key Laboratory of Crop Genetic Improvement, Wuhan, 430070, China
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Linbin Deng
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China
| | - Robert L Last
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, 48824, USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Wei Hua
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China
| | - Jun Liu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China
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3
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Zheng M, Pang X, Chen M, Tian L. Ultrafast energy quenching mechanism of LHCSR3-dependent photoprotection in Chlamydomonas. Nat Commun 2024; 15:4437. [PMID: 38789432 PMCID: PMC11126702 DOI: 10.1038/s41467-024-48789-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
Photosynthetic organisms have evolved an essential energy-dependent quenching (qE) mechanism to avoid any lethal damages caused by high light. While the triggering mechanism of qE has been well addressed, candidates for quenchers are often debated. This lack of understanding is because of the tremendous difficulty in measuring intact cells using transient absorption techniques. Here, we have conducted femtosecond pump-probe measurements to characterize this photophysical reaction using micro-sized cell fractions of the green alga Chlamydomonas reinhardtii that retain physiological qE function. Combined with kinetic modeling, we have demonstrated the presence of an ultrafast excitation energy transfer (EET) pathway from Chlorophyll a (Chl a) Qy to a carotenoid (car) S1 state, therefore proposing that this carotenoid, likely lutein1, is the quencher. This work has provided an easy-to-prepare qE active thylakoid membrane system for advanced spectroscopic studies and demonstrated that the energy dissipation pathway of qE is evolutionarily conserved from green algae to land plants.
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Affiliation(s)
- Mengyuan Zheng
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaojie Pang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming Chen
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
| | - Lijin Tian
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- China National Botanical Garden, Beijing, 100093, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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4
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Sardar S, Caferri R, Camargo FVA, Capaldi S, Ghezzi A, Dall'Osto L, D'Andrea C, Cerullo G, Bassi R. Site-Directed Mutagenesis of the Chlorophyll-Binding Sites Modulates Excited-State Lifetime and Chlorophyll-Xanthophyll Energy Transfer in the Monomeric Light-Harvesting Complex CP29. J Phys Chem Lett 2024; 15:3149-3158. [PMID: 38478725 DOI: 10.1021/acs.jpclett.3c02900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
We combine site-directed mutagenesis with picosecond time-resolved fluorescence and femtosecond transient absorption (TA) spectroscopies to identify excitation energy transfer (EET) processes between chlorophylls (Chls) and xanthophylls (Xant) in the minor antenna complex CP29 assembled inside nanodiscs, which result in quenching. When compared to WT CP29, a longer lifetime was observed in the A2 mutant, missing Chl a612, which closely interacts with Xant Lutein in site L1. Conversely, a shorter lifetime was obtained in the A5 mutant, in which the interaction between Chl a603 and Chl a609 is strengthened, shifting absorption to lower energy and enhancing Chl-Xant EET. Global analysis of TA data indicated that EET from Chl a Qy to a Car dark state S* is active in both the A2 and A5 mutants and that their rate constants are modulated by mutations. Our study provides experimental evidence that multiple Chl-Xant interactions are involved in the quenching activity of CP29.
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Affiliation(s)
- Samim Sardar
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Rubattino 81, 20134 Milan, Italy
| | - Roberto Caferri
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Franco V A Camargo
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza L. da Vinci 32, 20133 Milano, Italy
| | - Stefano Capaldi
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Alberto Ghezzi
- Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
| | - Luca Dall'Osto
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Cosimo D'Andrea
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Rubattino 81, 20134 Milan, Italy
- Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
| | - Giulio Cerullo
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza L. da Vinci 32, 20133 Milano, Italy
- Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
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5
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Accomasso D, Londi G, Cupellini L, Mennucci B. The nature of carotenoid S* state and its role in the nonphotochemical quenching of plants. Nat Commun 2024; 15:847. [PMID: 38286840 PMCID: PMC11258248 DOI: 10.1038/s41467-024-45090-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 01/15/2024] [Indexed: 01/31/2024] Open
Abstract
In plants, light-harvesting complexes serve as antennas to collect and transfer the absorbed energy to reaction centers, but also regulate energy transport by dissipating the excitation energy of chlorophylls. This process, known as nonphotochemical quenching, seems to be activated by conformational changes within the light-harvesting complex, but the quenching mechanisms remain elusive. Recent spectroscopic measurements suggest the carotenoid S* dark state as the quencher of chlorophylls' excitation. By investigating lutein embedded in different conformations of CP29 (a minor antenna in plants) via nonadiabatic excited state dynamics simulations, we reveal that different conformations of the complex differently stabilize the lutein s-trans conformer with respect to the dominant s-cis one. We show that the s-trans conformer presents the spectroscopic signatures of the S* state and rationalize its ability to accept energy from the closest excited chlorophylls, providing thus a relationship between the complex's conformation and the nonphotochemical quenching.
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Affiliation(s)
- Davide Accomasso
- Department of Chemistry and Industrial Chemistry, University of Pisa, 56124, Pisa, Italy.
- Faculty of Chemistry, University of Warsaw, 02-093, Warsaw, Poland.
| | - Giacomo Londi
- Department of Chemistry and Industrial Chemistry, University of Pisa, 56124, Pisa, Italy
| | - Lorenzo Cupellini
- Department of Chemistry and Industrial Chemistry, University of Pisa, 56124, Pisa, Italy
| | - Benedetta Mennucci
- Department of Chemistry and Industrial Chemistry, University of Pisa, 56124, Pisa, Italy.
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6
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Short A, Fay TP, Crisanto T, Mangal R, Niyogi KK, Limmer DT, Fleming GR. Kinetics of the xanthophyll cycle and its role in photoprotective memory and response. Nat Commun 2023; 14:6621. [PMID: 37857617 PMCID: PMC10587229 DOI: 10.1038/s41467-023-42281-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023] Open
Abstract
Efficiently balancing photochemistry and photoprotection is crucial for survival and productivity of photosynthetic organisms in the rapidly fluctuating light levels found in natural environments. The ability to respond quickly to sudden changes in light level is clearly advantageous. In the alga Nannochloropsis oceanica we observed an ability to respond rapidly to sudden increases in light level which occur soon after a previous high-light exposure. This ability implies a kind of memory. In this work, we explore the xanthophyll cycle in N. oceanica as a short-term photoprotective memory system. By combining snapshot fluorescence lifetime measurements with a biochemistry-based quantitative model, we show that short-term memory arises from the xanthophyll cycle. In addition, the model enables us to characterize the relative quenching abilities of the three xanthophyll cycle components. Given the ubiquity of the xanthophyll cycle in photosynthetic organisms the model described here will be of utility in improving our understanding of vascular plant and algal photoprotection with important implications for crop productivity.
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Affiliation(s)
- Audrey Short
- Graduate Group in Biophysics, University of California, Berkeley, CA, 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Kavli Energy Nanoscience Institute, Berkeley, CA, 94720, USA
| | - Thomas P Fay
- Department of Chemistry, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Thien Crisanto
- Molecular Biophysics and Integrated Bioimaging Division Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720, USA
| | - Ratul Mangal
- Department of Chemistry, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Krishna K Niyogi
- Molecular Biophysics and Integrated Bioimaging Division Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720, USA
| | - David T Limmer
- Kavli Energy Nanoscience Institute, Berkeley, CA, 94720, USA
- Department of Chemistry, University of California Berkeley, Berkeley, CA, 94720, USA
- Chemical Science Division Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Material Science Division Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Graham R Fleming
- Graduate Group in Biophysics, University of California, Berkeley, CA, 94720, USA.
- Molecular Biophysics and Integrated Bioimaging Division Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Kavli Energy Nanoscience Institute, Berkeley, CA, 94720, USA.
- Department of Chemistry, University of California Berkeley, Berkeley, CA, 94720, USA.
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7
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Petry S, Tremblay JC, Götze JP. Impact of Structure, Coupling Scheme, and State of Interest on the Energy Transfer in CP29. J Phys Chem B 2023; 127:7207-7219. [PMID: 37581578 DOI: 10.1021/acs.jpcb.3c01012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
The Qy and Bx excitation energy transfer (EET) in the minor light-harvesting complex CP29 (LHCII B4.1) antenna complex of Pisum sativum was characterized using a computational approach. We applied Förster resonance energy transfer (FRET) and the transition density cube (TDC) method to estimate the Coulombic coupling, based on a combination of classical molecular dynamics and quantum mechanics/molecular mechanics calculations. Employing TDC instead of FRET mostly affects the EET between chlorophylls (Chls) and carotenoids (Crts), as expected due to the Crts being spatially more challenging for FRET. Only between Chls, effects are found to be small (about only 0.1 EET efficiency change when introducing TDC instead of FRET). Effects of structural sampling were found to be small, illustrated by a small average standard deviation for the Qy state coupling elements (FRET/TDC: 0.97/0.94 cm-1). Due to the higher flexibility of the Bx state, the corresponding deviations are larger (FRET/TDC between Chl-Chl pairs: 17.58/22.67 cm-1, between Crt-Chl pairs: 62.58/31.63 cm-1). In summary, it was found for the Q band that the coupling between Chls varies only slightly depending on FRET or TDC, resulting in a minute effect on EET acceptor preference. In contrast, the coupling in the B band spectral region is found to be more affected. Here, the S2 (1Bu) states of the spatially challenging Crts may act as acceptors in addition to the B states of the Chls. Depending on FRET or TDC, several Chls show different Chl-to-Crt couplings. Interestingly, the EET between Chls or Crts in the B band is found to often outcompete the corresponding decay processes. The individual efficiencies for B band EET to Crts vary however strongly with the chosen coupling scheme (e.g., up to 0.29/0.99 FRET/TDC efficiency for the Chl a604/neoxanthin pair). Thus, the choice of the coupling scheme must involve a consideration of the state of interest.
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Affiliation(s)
- S Petry
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - J C Tremblay
- Laboratoire de Physique et Chimie Théoriques, CNRS-Université de Lorraine, 57070 Metz, France
| | - J P Götze
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
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8
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Gulyás Z, Székely A, Kulman K, Kocsy G. Light-Dependent Regulatory Interactions between the Redox System and miRNAs and Their Biochemical and Physiological Effects in Plants. Int J Mol Sci 2023; 24:8323. [PMID: 37176028 PMCID: PMC10179207 DOI: 10.3390/ijms24098323] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/03/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023] Open
Abstract
Light intensity and spectrum play a major role in the regulation of the growth, development, and stress response of plants. Changes in the light conditions affect the formation of reactive oxygen species, the activity of the antioxidants, and, consequently, the redox environment in the plant tissues. Many metabolic processes, thus the biogenesis and function of miRNAs, are redox-responsive. The miRNAs, in turn, can modulate various components of the redox system, and this process is also associated with the alteration in the intensity and spectrum of the light. In this review, we would like to summarise the possible regulatory mechanisms by which the alterations in the light conditions can influence miRNAs in a redox-dependent manner. Daily and seasonal fluctuations in the intensity and spectral composition of the light can affect the expression of miRNAs, which can fine-tune the various physiological and biochemical processes due to their effect on their target genes. The interactions between the redox system and miRNAs may be modulated by light conditions, and the proposed function of this regulatory network and its effect on the various biochemical and physiological processes will be introduced in plants.
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Affiliation(s)
- Zsolt Gulyás
- Agricultural Institute, Centre for Agricultural Research ELKH, Department of Biological Resources, 2462 Martonvásár, Hungary
| | - András Székely
- Agricultural Institute, Centre for Agricultural Research ELKH, Department of Biological Resources, 2462 Martonvásár, Hungary
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Kitti Kulman
- Agricultural Institute, Centre for Agricultural Research ELKH, Department of Biological Resources, 2462 Martonvásár, Hungary
| | - Gábor Kocsy
- Agricultural Institute, Centre for Agricultural Research ELKH, Department of Biological Resources, 2462 Martonvásár, Hungary
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9
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Navakoudis E, Stergiannakos T, Daskalakis V. A perspective on the major light-harvesting complex dynamics under the effect of pH, salts, and the photoprotective PsbS protein. PHOTOSYNTHESIS RESEARCH 2023; 156:163-177. [PMID: 35816266 PMCID: PMC10070230 DOI: 10.1007/s11120-022-00935-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
The photosynthetic apparatus is a highly modular assembly of large pigment-binding proteins. Complexes called antennae can capture the sunlight and direct it from the periphery of two Photosystems (I, II) to the core reaction centers, where it is converted into chemical energy. The apparatus must cope with the natural light fluctuations that can become detrimental to the viability of the photosynthetic organism. Here we present an atomic scale view of the photoprotective mechanism that is activated on this line of defense by several photosynthetic organisms to avoid overexcitation upon excess illumination. We provide a complete macroscopic to microscopic picture with specific details on the conformations of the major antenna of Photosystem II that could be associated with the switch from the light-harvesting to the photoprotective state. This is achieved by combining insight from both experiments and all-atom simulations from our group and the literature in a perspective article.
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Affiliation(s)
- Eleni Navakoudis
- Department of Chemical Engineering, Cyprus University of Technology, 95 Eirinis Street, 3603, Limassol, Cyprus
| | - Taxiarchis Stergiannakos
- Department of Chemical Engineering, Cyprus University of Technology, 95 Eirinis Street, 3603, Limassol, Cyprus
| | - Vangelis Daskalakis
- Department of Chemical Engineering, Cyprus University of Technology, 95 Eirinis Street, 3603, Limassol, Cyprus.
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10
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Cignoni E, Cupellini L, Mennucci B. Machine Learning Exciton Hamiltonians in Light-Harvesting Complexes. J Chem Theory Comput 2023; 19:965-977. [PMID: 36701385 PMCID: PMC9933434 DOI: 10.1021/acs.jctc.2c01044] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Indexed: 01/27/2023]
Abstract
We propose a machine learning (ML)-based strategy for an inexpensive calculation of excitonic properties of light-harvesting complexes (LHCs). The strategy uses classical molecular dynamics simulations of LHCs in their natural environment in combination with ML prediction of the excitonic Hamiltonian of the embedded aggregate of pigments. The proposed ML model can reproduce the effects of geometrical fluctuations together with those due to electrostatic and polarization interactions between the pigments and the protein. The training is performed on the chlorophylls of the major LHC of plants, but we demonstrate that the model is able to extrapolate well beyond the initial training set. Moreover, the accuracy in predicting the effects of the environment is tested on the simulation of the small changes observed in the absorption spectra of the wild-type and a mutant of a minor LHC.
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Affiliation(s)
- Edoardo Cignoni
- Dipartimento di Chimica e
Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124Pisa, Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e
Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124Pisa, Italy
| | - Benedetta Mennucci
- Dipartimento di Chimica e
Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124Pisa, Italy
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11
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Elias E, Liguori N, Croce R. The origin of pigment-binding differences in CP29 and LHCII: the role of protein structure and dynamics. PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES : OFFICIAL JOURNAL OF THE EUROPEAN PHOTOCHEMISTRY ASSOCIATION AND THE EUROPEAN SOCIETY FOR PHOTOBIOLOGY 2023:10.1007/s43630-023-00368-7. [PMID: 36740636 DOI: 10.1007/s43630-023-00368-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/13/2023] [Indexed: 02/07/2023]
Abstract
The first step of photosynthesis in plants is performed by the light-harvesting complexes (LHC), a large family of pigment-binding proteins embedded in the photosynthetic membranes. These complexes are conserved across species, suggesting that each has a distinct role. However, they display a high degree of sequence homology and their static structures are almost identical. What are then the structural features that determine their different properties? In this work, we compared the two best-characterized LHCs of plants: LHCII and CP29. Using molecular dynamics simulations, we could rationalize the difference between them in terms of pigment-binding properties. The data also show that while the loops between the helices are very flexible, the structure of the transmembrane regions remains very similar in the crystal and the membranes. However, the small structural differences significantly affect the excitonic coupling between some pigment pairs. Finally, we analyzed in detail the structure of the long N-terminus of CP29, showing that it is structurally stable and it remains on top of the membrane even in the absence of other proteins. Although the structural changes upon phosphorylation are minor, they can explain the differences in the absorption properties of the pigments observed experimentally.
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Affiliation(s)
- Eduard Elias
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Nicoletta Liguori
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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12
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Chiariello M, Grünewald F, Zarmiento-Garcia R, Marrink SJ. pH-Dependent Conformational Switch Impacts Stability of the PsbS Dimer. J Phys Chem Lett 2023; 14:905-911. [PMID: 36662680 PMCID: PMC9900633 DOI: 10.1021/acs.jpclett.2c03760] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 01/13/2023] [Indexed: 06/17/2023]
Abstract
The photosystem II PsbS protein triggers the photoprotective mechanism of plants by sensing the acidification of the thylakoid lumen. Despite the mechanism of action of PsbS would require a pH-dependent monomerization of the dimeric form, a clear connection between the pH-induced structural changes and the dimer stability is missing. Here, by applying constant pH coarse-grained and all-atom molecular dynamics simulations, we investigate the pH-dependent structural response of the PsbS dimer. We find that the pH variation leads to structural changes in the lumen-exposed helices, located at the dimeric interface, providing an effective switch between PsbS inactive and active form. Moreover, the monomerization free energies reveal that in the neutral pH conformation, where the network of H-bond interactions at the dimeric interface is destroyed, the protein-protein interaction is weaker. Our results show how the pH-dependent conformations of PsbS affect their dimerization propensity, which is at the basis of the photoprotective mechanism.
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Affiliation(s)
| | | | - Rubi Zarmiento-Garcia
- Groningen
Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 4, 9747
AG Groningen, The Netherlands
| | - Siewert J. Marrink
- Groningen
Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 4, 9747
AG Groningen, The Netherlands
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13
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Quan J, Zheng W, Tan J, Li Z, Wu M, Hong SB, Zhao Y, Zhu Z, Zang Y. Glutamic Acid and Poly-γ-glutamic Acid Enhanced the Heat Resistance of Chinese Cabbage ( Brassica rapa L. ssp. pekinensis) by Improving Carotenoid Biosynthesis, Photosynthesis, and ROS Signaling. Int J Mol Sci 2022; 23:11671. [PMID: 36232971 PMCID: PMC9570168 DOI: 10.3390/ijms231911671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/19/2022] [Accepted: 09/28/2022] [Indexed: 11/07/2022] Open
Abstract
Heat stress is one of the most common agrometeorological risks in crop production in the middle and lower reaches of the Yangtze River in China. This study aimed to investigate whether glutamic acid (Glu) or poly-γ-glutamic acid (γ-PGA) biostimulants can improve the thermotolerance of a cool-season Chinese cabbage (Brassica rapa L. ssp. pekinensis) crop. Priming with Glu (2.0 mM) or γ-PGA (20 mg·L-1) was conducted at the third leaf stage by applying as daily foliar sprays for 5 days before 5 days of heat stress (45 °C in 16-h light/35 °C in 8-h dark). Coupled with morpho-physiological and biochemical analyses, transcriptomes of Glu or γ-PGA-primed Chinese cabbage under heat stress were examined by RNA-seq analysis. The results showed that the thermotolerance conferred by Glu and γ-PGA priming was associated with the increased parameters of vegetative growth, gas exchange, and chlorophyll fluorescence. Compared with the control, the dry weights of plants treated with Glu and γ-PGA increased by 51.52% and 39.39%, respectively. Glu and γ-PGA application also significantly increased the contents of total chlorophyll by 42.21% and 23.12%, and carotenoid by 32.00% and 24.00%, respectively. In addition, Glu- and γ-PGA-primed plants markedly inhibited the levels of malondialdehyde, electrolyte leakage, and super-oxide anion radical, which was accompanied by enhanced activity levels of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD). Enrichment analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) categories within the differentially expressed genes (DEGs) functional clusters of RNA-seq data indicated that the expression levels of the genes for DNA replication, DNA repair system, linoleic acid metabolism, cysteine and methionine metabolism, glutathione metabolism, purine and pyrimidine metabolism, carotenoid biosynthesis, and plant-pathogen interaction were commonly up-regulated by both Glu and γ-PGA priming. Glu treatment enhanced the expression levels of the genes involved in aliphatic glucosinolate and 2-oxocarboxylic acid, while γ-PGA treatment activated carotenoid cleavage reaction to synthesize abscisic acid. Taken together, both Glu and γ-PGA have great potential for the preadaptation of Chinese cabbage seedlings to heat stress, with Glu being more effective than γ-PGA.
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Affiliation(s)
- Jin Quan
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 311300, China
| | - Weiwei Zheng
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 311300, China
| | - Jingru Tan
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 311300, China
| | - Zewei Li
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 311300, China
| | - Meifang Wu
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 311300, China
| | - Seung-Beom Hong
- Department of Biotechnology, University of Houston Clear Lake, Houston, TX 77058-1098, USA
| | - Yanting Zhao
- Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Zhujun Zhu
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 311300, China
| | - Yunxiang Zang
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 311300, China
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14
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Bru P, Steen CJ, Park S, Amstutz CL, Sylak-Glassman EJ, Lam L, Fekete A, Mueller MJ, Longoni F, Fleming GR, Niyogi KK, Malnoë A. The major trimeric antenna complexes serve as a site for qH-energy dissipation in plants. J Biol Chem 2022; 298:102519. [PMID: 36152752 PMCID: PMC9615032 DOI: 10.1016/j.jbc.2022.102519] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 09/08/2022] [Accepted: 09/10/2022] [Indexed: 11/28/2022] Open
Abstract
Plants and algae are faced with a conundrum: harvesting sufficient light to drive their metabolic needs while dissipating light in excess to prevent photodamage, a process known as nonphotochemical quenching. A slowly relaxing form of energy dissipation, termed qH, is critical for plants’ survival under abiotic stress; however, qH location in the photosynthetic membrane is unresolved. Here, we tested whether we could isolate subcomplexes from plants in which qH was induced that would remain in an energy-dissipative state. Interestingly, we found that chlorophyll (Chl) fluorescence lifetimes were decreased by qH in isolated major trimeric antenna complexes, indicating that they serve as a site for qH-energy dissipation and providing a natively quenched complex with physiological relevance to natural conditions. Next, we monitored the changes in thylakoid pigment, protein, and lipid contents of antenna with active or inactive qH but did not detect any evident differences. Finally, we investigated whether specific subunits of the major antenna complexes were required for qH but found that qH was insensitive to trimer composition. Because we previously observed that qH can occur in the absence of specific xanthophylls, and no evident changes in pigments, proteins, or lipids were detected, we tentatively propose that the energy-dissipative state reported here may stem from Chl–Chl excitonic interaction.
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Affiliation(s)
- Pierrick Bru
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, 901 87 Umeå, Sweden
| | - Collin J Steen
- Department of Chemistry, University of California, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division (formerly Physical Biosciences Division), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Kavli Energy Nanoscience Institute, Berkeley, CA 94720, USA
| | - Soomin Park
- Department of Chemistry, University of California, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division (formerly Physical Biosciences Division), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Kavli Energy Nanoscience Institute, Berkeley, CA 94720, USA; School of Energy, Materials and Chemical Engineering, Korea University of Technology and Education, Cheonan, Chungnam 31253, Republic of Korea
| | - Cynthia L Amstutz
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Emily J Sylak-Glassman
- Department of Chemistry, University of California, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division (formerly Physical Biosciences Division), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Lam Lam
- Molecular Biophysics and Integrated Bioimaging Division (formerly Physical Biosciences Division), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Kavli Energy Nanoscience Institute, Berkeley, CA 94720, USA; Graduate Group in Biophysics, University of California, Berkeley, CA 94720, USA
| | - Agnes Fekete
- Julius-von-Sachs-Institute, Biocenter, Pharmaceutical Biology, University of Wuerzburg, D-97082 Wuerzburg, Germany
| | - Martin J Mueller
- Julius-von-Sachs-Institute, Biocenter, Pharmaceutical Biology, University of Wuerzburg, D-97082 Wuerzburg, Germany
| | - Fiamma Longoni
- Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Graham R Fleming
- Department of Chemistry, University of California, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division (formerly Physical Biosciences Division), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Kavli Energy Nanoscience Institute, Berkeley, CA 94720, USA; Graduate Group in Biophysics, University of California, Berkeley, CA 94720, USA
| | - Krishna K Niyogi
- Molecular Biophysics and Integrated Bioimaging Division (formerly Physical Biosciences Division), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Alizée Malnoë
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, 901 87 Umeå, Sweden.
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15
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Pandit A. Structural dynamics of light harvesting proteins, photosynthetic membranes and cells observed with spectral editing solid-state NMR. J Chem Phys 2022; 157:025101. [DOI: 10.1063/5.0094446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photosynthetic light-harvesting complexes have a remarkable capacity to perform robust photo physics at ambient temperatures and in fluctuating environments. Protein conformational dynamics and membrane mobility are processes that contribute to the light-harvesting efficiencies and control photoprotective responses. This short review describes the application of Magic Angle Spinning (MAS) NMR spectroscopy for characterizing the structural dynamics of pigment, protein and thylakoid membrane components related to light harvesting and photoprotection. I will discuss the use of dynamics-based spectral editing solid-state NMR for distinguishing rigid and mobile components and assessing protein, pigment and lipid dynamics on sub-nanosecond to millisecond timescales. Dynamic spectral editing NMR has been applied to investigate Light-Harvesting Complex II (LHCII) protein conformational dynamics inside lipid bilayers and in native membranes. Furthermore, we used the NMR approach to assess thylakoid membrane dynamics. Finally, it is shown that dynamics-based spectral editing NMR, for reducing spectral complexity, by filtering motion-dependent signals, enabled us to follow processes in live photosynthetic cells.
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16
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Sarngadharan P, Maity S, Kleinekathöfer U. Spectral densities and absorption spectra of the core antenna complex CP43 from photosystem II. J Chem Phys 2022; 156:215101. [DOI: 10.1063/5.0091005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Besides absorbing light, the core antenna complex CP43 of photosystem II is of great importance in transferring excitation energy from the antenna complexes to the reaction center. Excitation energies, spectral densities, and linear absorption spectra of the complex have been evaluated by a multiscale approach. In this scheme, quantum mechanics/molecular mechanics molecular dynamics simulations are performed employing the parameterized density functional tight binding (DFTB) while the time-dependent long-range-corrected DFTB scheme is applied for the excited state calculations. The obtained average spectral density of the CP43 complex shows a very good agreement with experimental results. Moreover, the excitonic Hamiltonian of the system along with the computed site-dependent spectral densities was used to determine the linear absorption. While a Redfield-like approximation has severe shortcomings in dealing with the CP43 complex due to quasi-degenerate states, the non-Markovian full second-order cumulant expansion formalism is able to overcome the drawbacks. Linear absorption spectra were obtained, which show a good agreement with the experimental counterparts at different temperatures. This study once more emphasizes that by combining diverse techniques from the areas of molecular dynamics simulations, quantum chemistry, and open quantum systems, it is possible to obtain first-principle results for photosynthetic complexes, which are in accord with experimental findings.
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Affiliation(s)
- Pooja Sarngadharan
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Sayan Maity
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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17
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Cignoni E, Cupellini L, Mennucci B. A fast method for electronic couplings in embedded multichromophoric systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:304004. [PMID: 35552268 DOI: 10.1088/1361-648x/ac6f3c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Abstract
Electronic couplings are key to understanding exciton delocalization and transport in natural and artificial light harvesting processes. We develop a method to compute couplings in multichromophoric aggregates embedded in complex environments without running expensive quantum chemical calculations. We use a transition charge approximation to represent the quantum mechanical transition densities of the chromophores and an atomistic and polarizable classical model to describe the environment atoms. We extend our framework to estimate transition charges directly from the chromophore geometry, i.e., bypassing completely the quantum mechanical calculations using a regression approach. The method allows to rapidly compute accurate couplings for a large number of geometries along molecular dynamics trajectories.
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Affiliation(s)
- Edoardo Cignoni
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124, Pisa, Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124, Pisa, Italy
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124, Pisa, Italy
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18
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Sláma V, Cupellini L, Mennucci B. Excitonic Nature of Carotenoid–Phthalocyanine Dyads and Its Role in Transient Absorption Spectra. ACS PHYSICAL CHEMISTRY AU 2022; 2:206-215. [PMID: 35637783 PMCID: PMC9136948 DOI: 10.1021/acsphyschemau.1c00049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/13/2022] [Accepted: 01/18/2022] [Indexed: 11/28/2022]
Abstract
![]()
Artificial carotenoid–tetrapyrrole
dyads have been extensively
used as model systems to understand the quenching mechanisms that
occur in light-harvesting complexes during nonphotochemical quenching.
In particular, dyads containing a carotenoid covalently linked to
a zinc phthalocyanine have been studied by transient absorption spectroscopy,
and the observed signals have been interpreted in terms of an excitonically
coupled state involving the lowest excited states of the two fragments.
If present, such excitonic delocalization would have significant implications
on the mechanism of nonphotochemical quenching. Here, we use quantum
chemical calculations to show that this delocalization is not needed
to reproduce the transient absorption spectra. On the contrary, the
observed signals can be explained through excitonic couplings in the
higher-energy manifold of states. We also argue that the covalent
linkage between the two fragments allows for electronic communications,
which complicates the analysis of the spectra based on two independent
but coupled moieties. These findings call for a more thorough reassessment
of the photophysics in these dyads and its implications in the context
of natural nonphotochemical quenching.
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Affiliation(s)
- Vladislav Sláma
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
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19
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Cignoni E, Slama V, Cupellini L, Mennucci B. The atomistic modeling of light-harvesting complexes from the physical models to the computational protocol. J Chem Phys 2022; 156:120901. [DOI: 10.1063/5.0086275] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The function of light-harvesting complexes is determined by a complex network of dynamic interactions among all the different components: the aggregate of pigments, the protein, and the surrounding environment. Complete and reliable predictions on these types of composite systems can be only achieved with an atomistic description. In the last few decades, there have been important advances in the atomistic modeling of light-harvesting complexes. These advances have involved both the completeness of the physical models and the accuracy and effectiveness of the computational protocols. In this Perspective, we present an overview of the main theoretical and computational breakthroughs attained so far in the field, with particular focus on the important role played by the protein and its dynamics. We then discuss the open problems in their accurate modeling that still need to be addressed. To illustrate an effective computational workflow for the modeling of light harvesting complexes, we take as an example the plant antenna complex CP29 and its H111N mutant.
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Affiliation(s)
- Edoardo Cignoni
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Vladislav Slama
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
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20
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Gray C, Wei T, Polívka T, Daskalakis V, Duffy CDP. Trivial Excitation Energy Transfer to Carotenoids Is an Unlikely Mechanism for Non-photochemical Quenching in LHCII. FRONTIERS IN PLANT SCIENCE 2021; 12:797373. [PMID: 35095968 PMCID: PMC8792765 DOI: 10.3389/fpls.2021.797373] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/20/2021] [Indexed: 05/04/2023]
Abstract
Higher plants defend themselves from bursts of intense light via the mechanism of Non-Photochemical Quenching (NPQ). It involves the Photosystem II (PSII) antenna protein (LHCII) adopting a conformation that favors excitation quenching. In recent years several structural models have suggested that quenching proceeds via energy transfer to the optically forbidden and short-lived S 1 states of a carotenoid. It was proposed that this pathway was controlled by subtle changes in the relative orientation of a small number of pigments. However, quantum chemical calculations of S 1 properties are not trivial and therefore its energy, oscillator strength and lifetime are treated as rather loose parameters. Moreover, the models were based either on a single LHCII crystal structure or Molecular Dynamics (MD) trajectories about a single minimum. Here we try and address these limitations by parameterizing the vibronic structure and relaxation dynamics of lutein in terms of observable quantities, namely its linear absorption (LA), transient absorption (TA) and two-photon excitation (TPE) spectra. We also analyze a number of minima taken from an exhaustive meta-dynamical search of the LHCII free energy surface. We show that trivial, Coulomb-mediated energy transfer to S 1 is an unlikely quenching mechanism, with pigment movements insufficiently pronounced to switch the system between quenched and unquenched states. Modulation of S 1 energy level as a quenching switch is similarly unlikely. Moreover, the quenching predicted by previous models is possibly an artifact of quantum chemical over-estimation of S 1 oscillator strength and the real mechanism likely involves short-range interaction and/or non-trivial inter-molecular states.
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Affiliation(s)
- Callum Gray
- Digital Environment Research Institute (DERI), Queen Mary University of London, London, United Kingdom
| | - Tiejun Wei
- Digital Environment Research Institute (DERI), Queen Mary University of London, London, United Kingdom
| | - Tomáš Polívka
- Department of Physics, Faculty of Science, University of South Bohemia, Ceske Budejovice, Czechia
| | - Vangelis Daskalakis
- Department of Chemical Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Christopher D. P. Duffy
- Digital Environment Research Institute (DERI), Queen Mary University of London, London, United Kingdom
- *Correspondence: Christopher D. P. Duffy
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