1
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Gray C, Kailas L, Adams PG, Duffy CDP. Unravelling the fluorescence kinetics of light-harvesting proteins with simulated measurements. Biochim Biophys Acta Bioenerg 2024; 1865:149004. [PMID: 37699505 DOI: 10.1016/j.bbabio.2023.149004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 08/24/2023] [Accepted: 08/31/2023] [Indexed: 09/14/2023]
Abstract
The plant light-harvesting pigment-protein complex LHCII is the major antenna sub-unit of PSII and is generally (though not universally) accepted to play a role in photoprotective energy dissipation under high light conditions, a process known Non-Photochemical Quenching (NPQ). The underlying mechanisms of energy trapping and dissipation within LHCII are still debated. Various models have been proposed for the underlying molecular detail of NPQ, but they are often based on different interpretations of very similar transient absorption measurements of isolated complexes. Here we present a simulated measurement of the fluorescence decay kinetics of quenched LHCII aggregates to determine whether this relatively simple measurement can discriminate between different potential NPQ mechanisms. We simulate not just the underlying physics (excitation, energy migration, quenching and singlet-singlet annihilation) but also the signal detection and typical experimental data analysis. Comparing this to a selection of published fluorescence decay kinetics we find that: (1) Different proposed quenching mechanisms produce noticeably different fluorescence kinetics even at low (annihilation free) excitation density, though the degree of difference is dependent on pulse width. (2) Measured decay kinetics are consistent with most LHCII trimers becoming relatively slow excitation quenchers. A small sub-population of very fast quenchers produces kinetics which do not resemble any observed measurement. (3) It is necessary to consider at least two distinct quenching mechanisms in order to accurately reproduce experimental kinetics, supporting the idea that NPQ is not a simple binary switch.
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Affiliation(s)
- Callum Gray
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End, London E1 4NS, United Kingdom
| | - Lekshmi Kailas
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Peter G Adams
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End, London E1 4NS, United Kingdom.
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2
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Abstract
Carotenoids are an integral part of natural photosynthetic complexes, with tasks ranging from light harvesting to photoprotection. Their underlying energy deactivation network of optically dark and bright excited states is extremely efficient: after excitation of light with up to 2.5 eV of photon energy, the system relaxes back to ground state on a time scale of a few picoseconds. In this article, we summarize how a model based on the vibrational energy relaxation approach (VERA) explains the main characteristics of relaxation dynamics after one-photon excitation with special emphasis on the so-called S* state. Lineshapes after two-photon excitation are beyond the current model of VERA. We outline this future line of research in our article. In terms of experimental method development, we discuss which techniques are needed to better describe energy dissipation effects in carotenoids and within the first solvation shell.
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Affiliation(s)
- Václav Šebelík
- Dynamical Spectroscopy, Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching bei Munich, Germany
| | - Christopher D P Duffy
- Digital Environment Research Institute, Queen Mary University of London, London E1 4NS, U.K
| | - Erika Keil
- Dynamical Spectroscopy, Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching bei Munich, Germany
| | - Tomáš Polívka
- Department of Physics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.,Biology Centre, Institute of Plant Molecular Biology, Czech Academy of Sciences, Branišovská 1160/31, 370 05 České Budějovice, Czech Republic
| | - Jürgen Hauer
- Dynamical Spectroscopy, Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching bei Munich, Germany
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3
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Hancock AM, Son M, Nairat M, Wei T, Jeuken LJC, Duffy CDP, Schlau-Cohen GS, Adams PG. Ultrafast energy transfer between lipid-linked chromophores and plant light-harvesting complex II. Phys Chem Chem Phys 2021; 23:19511-19524. [PMID: 34524278 PMCID: PMC8442836 DOI: 10.1039/d1cp01628h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Light-Harvesting Complex II (LHCII) is a membrane protein found in plant chloroplasts that has the crucial role of absorbing solar energy and subsequently performing excitation energy transfer to the reaction centre subunits of Photosystem II. LHCII provides strong absorption of blue and red light, however, it has minimal absorption in the green spectral region where solar irradiance is maximal. In a recent proof-of-principle study, we enhanced the absorption in this spectral range by developing a biohybrid system where LHCII proteins together with lipid-linked Texas Red (TR) chromophores were assembled into lipid membrane vesicles. The utility of these systems was limited by significant LHCII quenching due to protein-protein interactions and heterogeneous lipid structures. Here, we organise TR and LHCII into a lipid nanodisc, which provides a homogeneous, well-controlled platform to study the interactions between TR molecules and single LHCII complexes. Fluorescence spectroscopy determined that TR-to-LHCII energy transfer has an efficiency of at least 60%, resulting in a 262% enhancement of LHCII fluorescence in the 525-625 nm range, two-fold greater than in the previous system. Ultrafast transient absorption spectroscopy revealed two time constants of 3.7 and 128 ps for TR-to-LHCII energy transfer. Structural modelling and theoretical calculations indicate that these timescales correspond to TR-lipids that are loosely- or tightly-associated with the protein, respectively, with estimated TR-to-LHCII separations of ∼3.5 nm and ∼1 nm. Overall, we demonstrate that a nanodisc-based biohybrid system provides an idealised platform to explore the photophysical interactions between extrinsic chromophores and membrane proteins with potential applications in understanding more complex natural or artificial photosynthetic systems.
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Affiliation(s)
- Ashley M Hancock
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Minjung Son
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Muath Nairat
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Tiejun Wei
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Lars J C Jeuken
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.,Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands
| | - Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Gabriela S Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Peter G Adams
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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4
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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. Front Plant Sci 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] [What about the content of this article? (0)] [Affiliation(s)] [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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5
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Abstract
A universal design principle underlies photosynthetic antenna systems
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Affiliation(s)
- Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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6
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Kim E, Watanabe A, Duffy CDP, Ruban AV, Minagawa J. Multimeric and monomeric photosystem II supercomplexes represent structural adaptations to low- and high-light conditions. J Biol Chem 2020; 295:14537-14545. [PMID: 32561642 DOI: 10.1074/jbc.ra120.014198] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/15/2020] [Indexed: 12/20/2022] Open
Abstract
An intriguing molecular architecture called the "semi-crystalline photosystem II (PSII) array" has been observed in the thylakoid membranes in vascular plants. It is an array of PSII-light-harvesting complex II (LHCII) supercomplexes that only appears in low light, but its functional role has not been clarified. Here, we identified PSII-LHCII supercomplexes in their monomeric and multimeric forms in low light-acclimated spinach leaves and prepared them using sucrose-density gradient ultracentrifugation in the presence of amphipol A8-35. When the leaves were acclimated to high light, only the monomeric forms were present, suggesting that the multimeric forms represent a structural adaptation to low light and that disaggregation of the PSII-LHCII supercomplex represents an adaptation to high light. Single-particle EM revealed that the multimeric PSII-LHCII supercomplexes are composed of two ("megacomplex") or three ("arraycomplex") units of PSII-LHCII supercomplexes, which likely constitute a fraction of the semi-crystalline PSII array. Further characterization with fluorescence analysis revealed that multimeric forms have a higher light-harvesting capability but a lower thermal dissipation capability than the monomeric form. These findings suggest that the configurational conversion of PSII-LHCII supercomplexes may serve as a structural basis for acclimation of plants to environmental light.
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Affiliation(s)
- Eunchul Kim
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan; Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya, Japan
| | - Akimasa Watanabe
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan; Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Jun Minagawa
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan; Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan.
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7
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Balevičius V, Duffy CDP. Excitation quenching in chlorophyll-carotenoid antenna systems: 'coherent' or 'incoherent'. Photosynth Res 2020; 144:301-315. [PMID: 32266612 PMCID: PMC7239839 DOI: 10.1007/s11120-020-00737-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 03/18/2020] [Indexed: 05/20/2023]
Abstract
Plants possess an essential ability to rapidly down-regulate light-harvesting in response to high light. This photoprotective process involves the formation of energy-quenching interactions between the chlorophyll and carotenoid pigments within the antenna of Photosystem II (PSII). The nature of these interactions is currently debated, with, among others, 'incoherent' or 'coherent' quenching models (or a combination of the two) suggested by a range of time-resolved spectroscopic measurements. In 'incoherent quenching', energy is transferred from a chlorophyll to a carotenoid and is dissipated due to the intrinsically short excitation lifetime of the latter. 'Coherent quenching' would arise from the quantum mechanical mixing of chlorophyll and carotenoid excited state properties, leading to a reduction in chlorophyll excitation lifetime. The key parameters are the energy gap, [Formula: see text] and the resonance coupling, J, between the two excited states. Coherent quenching will be the dominant process when [Formula: see text] i.e., when the two molecules are resonant, while the quenching will be largely incoherent when [Formula: see text] One would expect quenching to be energetically unfavorable for [Formula: see text] The actual dynamics of quenching lie somewhere between these limiting regimes and have non-trivial dependencies of both J and [Formula: see text] Using the Hierarchical Equation of Motion (HEOM) formalism we present a detailed theoretical examination of these excitation dynamics and their dependence on slow variations in J and [Formula: see text] We first consider an isolated chlorophyll-carotenoid dimer before embedding it within a PSII antenna sub-unit (LHCII). We show that neither energy transfer, nor the mixing of excited state lifetimes represent unique or necessary pathways for quenching and in fact discussing them as distinct quenching mechanisms is misleading. However, we do show that quenching cannot be switched 'on' and 'off' by fine tuning of [Formula: see text] around the resonance point, [Formula: see text] Due to the large reorganization energy of the carotenoid excited state, we find that the presence (or absence) of coherent interactions have almost no impact of the dynamics of quenching. Counter-intuitively significant quenching is present even when the carotenoid excited state lies above that of the chlorophyll. We also show that, above a rather small threshold value of [Formula: see text]quenching becomes less and less sensitive to J (since in the window [Formula: see text] the overall lifetime is independent of it). The requirement for quenching appear to be only that [Formula: see text] Although the coherent/incoherent character of the quenching can vary, the overall kinetics are likely robust with respect to fluctuations in J and [Formula: see text] This may be the basis for previous observations of NPQ with both coherent and incoherent features.
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Affiliation(s)
- Vytautas Balevičius
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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8
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Wei T, Balevičius V, Polívka T, Ruban AV, Duffy CDP. How carotenoid distortions may determine optical properties: lessons from the Orange Carotenoid Protein. Phys Chem Chem Phys 2019; 21:23187-23197. [PMID: 31612872 DOI: 10.1039/c9cp03574e] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carotenoids in photosynthetic proteins carry out the dual function of harvesting light and defending against photo-damage by quenching excess energy. The latter involves the low-lying, dark, excited state labelled S1. Here "dark" means optically-forbidden, a property that is often attributed to molecular symmetry, which leads to speculation that its optical properties may be strongly-perturbed by structural distortions. This has been both explicitly and implicitly proposed as an important feature of photo-protective energy quenching. Here we present a theoretical analysis of the relationship between structural distortions and S1 optical properties. We outline how S1 is dark not because of overall geometric symmetry but because of a topological symmetry related to bond length alternation in the conjugated backbone. Taking the carotenoid echinenone as an example and using a combination of molecular dynamics, quantum chemistry, and the theory of spectral lineshapes, we show that distortions that break this symmetry are extremely stiff. They are therefore absent in solution and only marginally present in even a very highly-distorted protein binding pocket such as in the Orange Carotenoid Protein (OCP). S1 remains resolutely optically-forbidden despite any breaking of bulk molecular symmetry by the protein environment. However, rotations of partially conjugated end-rings can result in fine tuning of the S1 transition density which may exert some influence on interactions with neighbouring chromophores.
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Affiliation(s)
- Tiejun Wei
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
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9
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Daskalakis V, Maity S, Hart CL, Stergiannakos T, Duffy CDP, Kleinekathöfer U. Structural Basis for Allosteric Regulation in the Major Antenna Trimer of Photosystem II. J Phys Chem B 2019; 123:9609-9615. [DOI: 10.1021/acs.jpcb.9b09767] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Vangelis Daskalakis
- Department of Environmental Science and Technology, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3603, Limassol, Cyprus
| | - Sayan Maity
- Department of Physics & Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Cameron Lewis Hart
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Taxiarchis Stergiannakos
- Department of Environmental Science and Technology, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3603, Limassol, Cyprus
| | - Christopher D. P. Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Ulrich Kleinekathöfer
- Department of Physics & Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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10
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Balevičius V, Wei T, Di Tommaso D, Abramavicius D, Hauer J, Polívka T, Duffy CDP. The full dynamics of energy relaxation in large organic molecules: from photo-excitation to solvent heating. Chem Sci 2019; 10:4792-4804. [PMID: 31183032 PMCID: PMC6521204 DOI: 10.1039/c9sc00410f] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/29/2019] [Indexed: 01/04/2023] Open
Abstract
In some molecular systems, such as nucleobases, polyenes or sunscreens, substantial amounts of photo-excitation energy are dissipated on a sub-picosecond time scale. Where does this energy go or among which degrees of freedom it is being distributed at such early times?
In some molecular systems, such as nucleobases, polyenes or the active ingredients of sunscreens, substantial amounts of photo-excitation energy are dissipated on a sub-picosecond time scale, raising questions such as: where does this energy go or among which degrees of freedom it is being distributed at such early times? Here we use transient absorption spectroscopy to track excitation energy dispersing from the optically accessible vibronic subsystem into the remaining vibrational subsystem of the solute and solvent. Monitoring the flow of energy during vibrational redistribution enables quantification of local molecular heating. Subsequent heat dissipation away from the solute molecule is characterized by classical thermodynamics and molecular dynamics simulations. Hence, we present a holistic approach that tracks the internal temperature and vibronic distribution from the act of photo-excitation to the restoration of the global equilibrium. Within this framework internal vibrational redistribution and vibrational cooling are emergent phenomena. We demonstrate the validity of the framework by examining a highly controversial example, carotenoids. We show that correctly accounting for the local temperature unambiguously explains their energetically and temporally congested spectral dynamics without the ad hoc postulation of additional ‘dark’ states. An immediate further application of this approach would be to monitor the excitation and thermal dynamics of pigment–protein systems.
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Affiliation(s)
- Vytautas Balevičius
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Tiejun Wei
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Devis Di Tommaso
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Darius Abramavicius
- Institute of Chemical Physics , Vilnius University , Sauletekio av. 9 , Vilnius , LT-10222 , Lithuania
| | - Jürgen Hauer
- Fakultät für Chemie , Technical University of Munich , Lichtenbergstraße 4 , D-85748 Garching , Germany.,Photonics Institute , TU Wien , Gußhausstraße 27 , 1040 Vienna , Austria
| | - Tomas Polívka
- Institute of Physics and Biophysics , Faculty of Science , University of South Bohemia , Branišovská 1760 , 37005 České Budějovice , Czech Republic
| | - Christopher D P Duffy
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
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11
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Fox KF, Balevičius V, Chmeliov J, Valkunas L, Ruban AV, Duffy CDP. The carotenoid pathway: what is important for excitation quenching in plant antenna complexes? Phys Chem Chem Phys 2017; 19:22957-22968. [DOI: 10.1039/c7cp03535g] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Plant light-harvesting is regulated by the Non-Photochemical Quenching (NPQ) mechanism involving the slow trapping of excitation energy by carotenoids in the Photosystem II (PSII) antenna in response to high light.
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Affiliation(s)
- Kieran F. Fox
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London E1 4NS
- UK
| | - Vytautas Balevičius
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London E1 4NS
- UK
| | - Jevgenij Chmeliov
- Department of Theoretical Physics
- Faculty of Physics
- Vilnius University
- Sauletekio Ave. 9
- 10222 Vilnius
| | - Leonas Valkunas
- Department of Theoretical Physics
- Faculty of Physics
- Vilnius University
- Sauletekio Ave. 9
- 10222 Vilnius
| | - Alexander V. Ruban
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London E1 4NS
- UK
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12
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Chmeliov J, Gelzinis A, Songaila E, Augulis R, Duffy CDP, Ruban AV, Valkunas L. The nature of self-regulation in photosynthetic light-harvesting antenna. Nat Plants 2016; 2:16045. [PMID: 27243647 DOI: 10.1038/nplants.2016.45] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 03/09/2016] [Indexed: 05/08/2023]
Abstract
The photosynthetic apparatus of green plants is well known for its extremely high efficiency that allows them to operate under dim light conditions. On the other hand, intense sunlight may result in overexcitation of the light-harvesting antenna and the formation of reactive compounds capable of 'burning out' the whole photosynthetic unit. Non-photochemical quenching is a self-regulatory mechanism utilized by green plants on a molecular level that allows them to safely dissipate the detrimental excess excitation energy as heat. Although it is believed to take place in the plant's major light-harvesting complexes (LHC) II, there is still no consensus regarding its molecular nature. To get more insight into its physical origin, we performed high-resolution time-resolved fluorescence measurements of LHCII trimers and their aggregates across a wide temperature range. Based on simulations of the excitation energy transfer in the LHCII aggregate, we associate the red-emitting state, having fluorescence maximum at ∼700 nm, with the partial mixing of excitonic and chlorophyll-chlorophyll charge transfer states. On the other hand, the quenched state has a totally different nature and is related to the incoherent excitation transfer to the short-lived carotenoid excited states. Our results also show that the required level of photoprotection in vivo can be achieved by a very subtle change in the number of LHCIIs switched to the quenched state.
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Affiliation(s)
- Jevgenij Chmeliov
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
| | - Andrius Gelzinis
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
| | - Egidijus Songaila
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
| | - Ramūnas Augulis
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
| | - Christopher D P Duffy
- The School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Alexander V Ruban
- The School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Leonas Valkunas
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
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13
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Chmeliov J, Bricker WP, Lo C, Jouin E, Valkunas L, Ruban AV, Duffy CDP. An ‘all pigment’ model of excitation quenching in LHCII. Phys Chem Chem Phys 2015; 17:15857-67. [DOI: 10.1039/c5cp01905b] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This work presents the first all-pigment microscopic model of a major light-harvesting complex of plants and the first attempt to capture the dissipative character of the known structure.
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Affiliation(s)
- Jevgenij Chmeliov
- Department of Theoretical Physics
- Faculty of Physics
- Vilnius University
- LT-10222 Vilnius
- Lithuania
| | - William P. Bricker
- Department of Energy
- Environmental and Chemical Engineering
- Washington University in St. Louis
- Saint Louis
- USA
| | - Cynthia Lo
- Department of Energy
- Environmental and Chemical Engineering
- Washington University in St. Louis
- Saint Louis
- USA
| | - Elodie Jouin
- The School of Biological and Chemical Sciences
- Queen Mary
- University of London
- London E1 4NS
- UK
| | - Leonas Valkunas
- Department of Theoretical Physics
- Faculty of Physics
- Vilnius University
- LT-10222 Vilnius
- Lithuania
| | - Alexander V. Ruban
- The School of Biological and Chemical Sciences
- Queen Mary
- University of London
- London E1 4NS
- UK
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14
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Duffy CDP, Pandit A, Ruban AV. Modeling the NMR signatures associated with the functional conformational switch in the major light-harvesting antenna of photosystem II in higher plants. Phys Chem Chem Phys 2014; 16:5571-80. [PMID: 24513782 DOI: 10.1039/c3cp54971b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The major photosystem II antenna complex, LHCII, possesses an intrinsic conformational switch linked to the formation of a photoprotective, excitation-quenching state. Recent solid state NMR experiments revealed that aggregation-induced quenching in (13)C-enriched LHCII from C. reinhardtii is associated with changes to the chemical shifts of three specific (13)C atoms in the Chla conjugated macrocycle. We performed DFT-based NMR calculations on the strongly-quenched crystal structure of LHCII (taken from spinach). We demonstrate that specific Chla-xanthophyll interactions in the quenched structure lead to changes in the Chla(13)C chemical shifts that are qualitatively similar to those observed by solid state NMR. We propose that these NMR changes are due to modulations in Chla-xanthophyll associations that occur due to a quenching-associated functional conformation change in the lutein and neoxanthin domains of LHCII. The combination of solid-state NMR and theoretical modeling is therefore a powerful tool for assessing functional conformational switching in the photosystem II antenna.
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Affiliation(s)
- Christopher D P Duffy
- The School of Biological and Chemical Science, Queen Mary, University of London, Mile End, London E1 4NS, UK.
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15
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Belgio E, Duffy CDP, Ruban AV. Switching light harvesting complex II into photoprotective state involves the lumen-facing apoprotein loop. Phys Chem Chem Phys 2013; 15:12253-61. [PMID: 23771239 DOI: 10.1039/c3cp51925b] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In higher plants, high light conditions trigger the activation of non-photochemical quenching (NPQ), a process of photoprotective light energy dissipation, via acidification of the chloroplast lumen. Spectral changes occurring in the neoxanthin domain of the major light harvesting antenna complex (LHCII) have previously provided indirect evidence of a protein conformational switch during NPQ. We report here of two recombinant LHCII complexes mutated at the level of lumenal loop with altered quenching capacity with respect to the control. Replacement of the acidic lumenal-facing residue aspartate 111 (D111) with neutral valine (V111) yielded a recombinant complex with increased quenching capacity under low pH, due to a shift of the pK by 1 pH unit. The increase in total quenching was consistent with 40% reduction in the relative chlorophyll fluorescence lifetime and was accompanied by a lower energy emitting state of the mutant, as demonstrated by 77 K fluorescence spectroscopy. On the other hand, replacement of acidic glutamate 94 (E94) with glycine (G94) resulted in reduction of the fluorescence quenching yield attained at low pH. These results show for the first time that a subtle change in the LHCII apoprotein structure at the level of the lumenal loop induced by single aminoacid mutagenesis can affect protein sensitivity to pH leading to the establishment of NPQ. This work opens a potential avenue for manipulation of light harvesting efficiency in the natural antenna pigment-protein complexes that can be used for the creation of hybrid light energy conversion systems in future.
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Affiliation(s)
- Erica Belgio
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, Fogg Building, London E1 4NS, UK
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16
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Ilioaia C, Duffy CDP, Johnson MP, Ruban AV. Changes in the Energy Transfer Pathways within Photosystem II Antenna Induced by Xanthophyll Cycle Activity. J Phys Chem B 2013; 117:5841-7. [DOI: 10.1021/jp402469d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cristian Ilioaia
- Institut de
Biologie et de Technologie
de Saclay, CEA Saclay, 91191 Gif/Yvette
Cedex, France
| | - Christopher D. P. Duffy
- School of
Biological and Chemical
Sciences, Queen Mary University of London, Mile End, Bancroft Road, London E1 4NS, United Kingdom
| | - Matthew P. Johnson
- Department of Molecular Biology
and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Alexander V. Ruban
- School of
Biological and Chemical
Sciences, Queen Mary University of London, Mile End, Bancroft Road, London E1 4NS, United Kingdom
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17
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Affiliation(s)
- Mindaugas Macernis
- Theoretical Physics Department,
Faculty of Physics, Vilnius University,
Saulėtekio al. 9, LT-10222 Vilnius, Lithuania
- Center for Physical Sciences and Technology, Savanorių 231, LT-02300
Vilnius, Lithuania
| | - Juozas Sulskus
- Theoretical Physics Department,
Faculty of Physics, Vilnius University,
Saulėtekio al. 9, LT-10222 Vilnius, Lithuania
| | - Christopher D. P. Duffy
- School
of Biological and Chemical
Sciences, Queen Mary University of London, Mile End Road, London E1 4TN, U.K
| | - Alexander V. Ruban
- School
of Biological and Chemical
Sciences, Queen Mary University of London, Mile End Road, London E1 4TN, U.K
| | - Leonas Valkunas
- Theoretical Physics Department,
Faculty of Physics, Vilnius University,
Saulėtekio al. 9, LT-10222 Vilnius, Lithuania
- Center for Physical Sciences and Technology, Savanorių 231, LT-02300
Vilnius, Lithuania
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18
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Affiliation(s)
- Christopher D. P. Duffy
- School of Biological and
Chemical Sciences, Queen Mary University of London, Mile End Road, London
E1 4NS, United Kingdom
| | - Alexander V. Ruban
- School of Biological and
Chemical Sciences, Queen Mary University of London, Mile End Road, London
E1 4NS, United Kingdom
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19
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Goral TK, Johnson MP, Duffy CDP, Brain APR, Ruban AV, Mullineaux CW. Light-harvesting antenna composition controls the macrostructure and dynamics of thylakoid membranes in Arabidopsis. Plant J 2012; 69:289-301. [PMID: 21919982 DOI: 10.1111/j.1365-313x.2011.04790.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We characterized a set of Arabidopsis mutants deficient in specific light-harvesting proteins, using freeze-fracture electron microscopy to probe the organization of complexes in the membrane and confocal fluorescence recovery after photobleaching to probe the dynamics of thylakoid membranes within intact chloroplasts. The same methods were used to characterize mutants lacking or over-expressing PsbS, a protein related to light-harvesting complexes that appears to play a role in regulation of photosynthetic light harvesting. We found that changes in the complement of light-harvesting complexes and PsbS have striking effects on the photosystem II macrostructure, and that these effects correlate with changes in the mobility of chlorophyll proteins within the thylakoid membrane. The mobility of chlorophyll proteins was found to correlate with the extent of photoprotective non-photochemical quenching, consistent with the idea that non-photochemical quenching involves extensive re-organization of complexes in the membrane. We suggest that a key feature of the physiological function of PsbS is to decrease the formation of ordered semi-crystalline arrays of photosystem II in the low-light state. Thus the presence of PsbS leads to an increase in the fluidity of the membrane, accelerating the re-organization of the photosystem II macrostructure that is necessary for induction of non-photochemical quenching.
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Affiliation(s)
- Tomasz K Goral
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E14NS, UK
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20
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Valkunas L, Chmeliov J, Trinkunas G, Duffy CDP, van Grondelle R, Ruban AV. Excitation Migration, Quenching, and Regulation of Photosynthetic Light Harvesting in Photosystem II. J Phys Chem B 2011; 115:9252-60. [DOI: 10.1021/jp2014385] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Leonas Valkunas
- Institute of Physics, Center for Physical Sciences and Technology, Savanoriu Ave 231, LT-02300 Vilnius, Lithuania
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Ave 9, build. 3, LT-10222 Vilnius, Lithuania
| | - Jevgenij Chmeliov
- Institute of Physics, Center for Physical Sciences and Technology, Savanoriu Ave 231, LT-02300 Vilnius, Lithuania
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Ave 9, build. 3, LT-10222 Vilnius, Lithuania
| | - Gediminas Trinkunas
- Institute of Physics, Center for Physical Sciences and Technology, Savanoriu Ave 231, LT-02300 Vilnius, Lithuania
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Ave 9, build. 3, LT-10222 Vilnius, Lithuania
| | - Christopher D. P. Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, VU Universiteit Amsterdam, De Boelelaan 1081, NL-1081 HV Amsterdam, The Netherlands
| | - Alexander V. Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
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21
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Ruban AV, Johnson MP, Duffy CDP. The photoprotective molecular switch in the photosystem II antenna. Biochim Biophys Acta 2011; 1817:167-81. [PMID: 21569757 DOI: 10.1016/j.bbabio.2011.04.007] [Citation(s) in RCA: 473] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 03/28/2011] [Accepted: 04/01/2011] [Indexed: 10/18/2022]
Abstract
We have reviewed the current state of multidisciplinary knowledge of the photoprotective mechanism in the photosystem II antenna underlying non-photochemical chlorophyll fluorescence quenching (NPQ). The physiological need for photoprotection of photosystem II and the concept of feed-back control of excess light energy are described. The outline of the major component of nonphotochemical quenching, qE, is suggested to comprise four key elements: trigger (ΔpH), site (antenna), mechanics (antenna dynamics) and quencher(s). The current understanding of the identity and role of these qE components is presented. Existing opinions on the involvement of protons, different LHCII antenna complexes, the PsbS protein and different xanthophylls are reviewed. The evidence for LHCII aggregation and macrostructural reorganization of photosystem II and their role in qE are also discussed. The models describing the qE locus in LHCII complexes, the pigments involved and the evidence for structural dynamics within single monomeric antenna complexes are reviewed. We suggest how PsbS and xanthophylls may exert control over qE by controlling the affinity of LHCII complexes for protons with reference to the concepts of hydrophobicity, allostery and hysteresis. Finally, the physics of the proposed chlorophyll-chlorophyll and chlorophyll-xanthophyll mechanisms of energy quenching is explained and discussed. This article is part of a Special Issue entitled: Photosystem II.
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Affiliation(s)
- Alexander V Ruban
- Queen Mary Universityof London, School of Biological & Chemical Sciences, Mile Enf Road, London E1 4TN, UK.
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22
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Ilioaia C, Johnson MP, Duffy CDP, Pascal AA, van Grondelle R, Robert B, Ruban AV. Origin of absorption changes associated with photoprotective energy dissipation in the absence of zeaxanthin. J Biol Chem 2010; 286:91-8. [PMID: 21036900 DOI: 10.1074/jbc.m110.184887] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To prevent photo-oxidative damage to the photosynthetic membrane in strong light, plants dissipate excess absorbed light energy as heat in a mechanism known as non-photochemical quenching (NPQ). NPQ is triggered by the trans-membrane proton gradient (ΔpH), which causes the protonation of the photosystem II light-harvesting antenna (LHCII) and the PsbS protein, as well as the de-epoxidation of the xanthophyll violaxanthin to zeaxanthin. The combination of these factors brings about formation of dissipative pigment interactions that quench the excess energy. The formation of NPQ is associated with certain absorption changes that have been suggested to reflect a conformational change in LHCII brought about by its protonation. The light-minus-dark recovery absorption difference spectrum is characterized by a series of positive and negative bands, the best known of which is ΔA(535). Light-minus-dark recovery resonance Raman difference spectra performed at the wavelength of the absorption change of interest allows identification of the pigment responsible from its unique vibrational signature. Using this technique, the origin of ΔA(535) was previously shown to be a subpopulation of red-shifted zeaxanthin molecules. In the absence of zeaxanthin (and antheraxanthin), a proportion of NPQ remains, and the ΔA(535) change is blue-shifted to 525 nm (ΔA(525)). Using resonance Raman spectroscopy, it is shown that the ΔA(525) absorption change in Arabidopsis leaves lacking zeaxanthin belongs to a red-shifted subpopulation of violaxanthin molecules formed during NPQ. The presence of the same ΔA(535) and ΔA(525) Raman signatures in vitro in aggregated LHCII, containing zeaxanthin and violaxanthin, respectively, leads to a new proposal for the origin of the xanthophyll red shifts associated with NPQ.
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Affiliation(s)
- Cristian Ilioaia
- Commisariat à l'Energie Atomique, Institut de Biologie et Technologies de Saclay (iBiTecS), CNRS Unité de Recherche Associée 2096, Gif sur Yvette, F-91191 France.
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23
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Duffy CDP, Ruban AV, Barford W. Theoretical Investigation of the Role of Strongly Coupled Chlorophyll Dimers in Photoprotection of LHCII. J Phys Chem B 2008; 112:12508-15. [DOI: 10.1021/jp804571k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christopher D. P. Duffy
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom; School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom; and Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Alexander V. Ruban
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom; School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom; and Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - William Barford
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom; School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom; and Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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