1
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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
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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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2
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Ravensbergen J, Pillai S, Méndez-Hernández DD, Frese RN, van Grondelle R, Gust D, Moore TA, Moore AL, Kennis JTM. Dual Singlet Excited-State Quenching Mechanisms in an Artificial Caroteno-Phthalocyanine Light Harvesting Antenna. ACS PHYSICAL CHEMISTRY AU 2022; 2:59-67. [PMID: 35098245 PMCID: PMC8796278 DOI: 10.1021/acsphyschemau.1c00008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/29/2021] [Accepted: 09/29/2021] [Indexed: 11/29/2022]
Abstract
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Under excess illumination,
photosystem II of plants dissipates
excess energy through the quenching of chlorophyll fluorescence in
the light harvesting antenna. Various models involving chlorophyll
quenching by carotenoids have been proposed, including (i) direct
energy transfer from chlorophyll to the low-lying optically forbidden
carotenoid S1 state, (ii) formation of a collective quenched
chlorophyll–carotenoid S1 excitonic state, (iii)
chlorophyll–carotenoid charge separation and recombination,
and (iv) chlorophyll–chlorophyll charge separation and recombination.
In previous work, the first three processes were mimicked in model
systems: in a Zn-phthalocyanine–carotenoid dyad with an amide
linker, direct energy transfer was observed by femtosecond transient
absorption spectroscopy, whereas in a Zn-phthalocyanine–carotenoid
dyad with an amine linker excitonic quenching was demonstrated. Here,
we present a transient absorption spectroscopic study on a Zn-phthalocyanine–carotenoid
dyad with a phenylene linker. We observe that two quenching phases
of the phthalocyanine excited state exist at 77 and 213 ps in addition
to an unquenched phase at 2.7 ns. Within our instrument response of
∼100 fs, carotenoid S1 features rise which point
at an excitonic quenching mechanism. Strikingly, we observe an additional
rise of carotenoid S1 features at 3.6 ps, which shows that
a direct energy transfer mechanism in an inverted kinetics regime
is also in effect. We assign the 77 ps decay component to excitonic
quenching and the 3.6 ps/213 ps rise and decay components to direct
energy transfer. Our results indicate that dual quenching mechanisms
may be active in the same molecular system, in addition to an unquenched
fraction. Computational chemistry results indicate the presence of
multiple conformers where one of the dihedral angles of the phenylene
linker assumes distinct values. We propose that the parallel quenching
pathways and the unquenched fraction result from such conformational
subpopulations. Our results suggest that it is possible to switch
between different regimes of quenching and nonquenching through a
conformational change on the same molecule, offering insights into
potential mechanisms used in biological photosynthesis to adapt to
light intensity changes on fast time scales.
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Affiliation(s)
- Janneke Ravensbergen
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Smitha Pillai
- School of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1605, United States
| | | | - Raoul N. Frese
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Devens Gust
- School of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1605, United States
| | - Thomas A. Moore
- School of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1605, United States
| | - Ana L. Moore
- School of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1605, United States
| | - John T. M. Kennis
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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3
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Gacek DA, Betke A, Nowak J, Lokstein H, Walla PJ. Two-photon absorption and excitation spectroscopy of carotenoids, chlorophylls and pigment-protein complexes. Phys Chem Chem Phys 2021; 23:8731-8738. [PMID: 33876032 DOI: 10.1039/d1cp00656h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In addition to (bacterio)chlorophylls, (B)Chls, photosynthetic pigment-protein complexes bind carotenoids (Cars) that fulfil various important functions which are not fully understood, yet. However, certain excited states of Cars are optically one-photon forbidden ("dark") and can potentially undergo excitation energy transfer (EET) to (B)Chls following two-photon absorption (TPA). The amount of EET is reflected by the differences in TPA and two-photon excitation (TPE) spectra of a complex (multi-pigment) system. Since it is technically and analytically demanding to resolve optically forbidden states, different studies reported varying contributions of Cars and Chls to TPE/TPA spectra. In a study using well-defined 1 : 1 Car-tetrapyrrole dyads TPE contributions of tetrapyrrole molecules, including Chls, and Cars were measured. In these experiments, TPE of Cars dominated over Chl a TPE in a broad wavelength range. Another study suggested only minor contributions of Cars to TPE spectra of pigment-protein complexes such as the plant main light-harvesting complex (LHCII), in particular for wavelengths longer than ∼600/1200 nm. By joining forces and a combined analysis of all available data by both teams, we try to resolve this apparent contradiction. Here, we demonstrate that reconstruction of a wide spectral range of TPE for LHCII and photosystem I (PSI) requires both, significant Car and Chl contributions. Direct comparison of TPE spectra obtained in both studies demonstrates a good agreement of the primary data. We conclude that in TPE spectra of LHCII and PSI, the contribution of Chls is dominating above 600/1200 nm, whereas the contributions of forbidden Car states increase particularly at wavelengths shorter than 600/1200 nm. Estimates of Car contributions to TPA as well as TPE spectra are given for various wavelengths.
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Affiliation(s)
- Daniel A Gacek
- Technische Universität Braunschweig, Institute for Physical and Theoretical Chemistry, Department for Biophysical Chemistry, Gaußstr. 17, 38106 Braunschweig, Germany.
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4
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Balevičius V, Duffy CDP. Excitation quenching in chlorophyll-carotenoid antenna systems: 'coherent' or 'incoherent'. PHOTOSYNTHESIS RESEARCH 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] [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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5
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Gacek DA, Holleboom CP, Liao PN, Negretti M, Croce R, Walla PJ. Carotenoid dark state to chlorophyll energy transfer in isolated light-harvesting complexes CP24 and CP29. PHOTOSYNTHESIS RESEARCH 2020; 143:19-30. [PMID: 31659623 DOI: 10.1007/s11120-019-00676-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 09/11/2019] [Indexed: 06/10/2023]
Abstract
We present a comparison of the energy transfer between carotenoid dark states and chlorophylls for the minor complexes CP24 and CP29. To elucidate the potential involvement of certain carotenoid-chlorophyll coupling sites in fluorescence quenching of distinct complexes, varying carotenoid compositions and mutants lacking chlorophylls at specific binding sites were examined. Energy transfers between carotenoid dark states and chlorophylls were compared using the coupling parameter, [Formula: see text], which is calculated from the chlorophyll fluorescence observed after preferential carotenoid two-photon excitation. In CP24, artificial reconstitution with zeaxanthin leads to a significant reduction in the chlorophyll fluorescence quantum yield, [Formula: see text], and a considerable increase in [Formula: see text]. Similar effects of zeaxanthin were also observed in certain samples of CP29. In CP29, also the replacement of violaxanthin by the sole presence of lutein results in a significant quenching and increased [Formula: see text]. In contrast, the replacement of violaxanthin by lutein in CP24 is not significantly increasing [Formula: see text]. In general, these findings provide evidence that modification of the electronic coupling between carotenoid dark states and chlorophylls by changing carotenoids at distinct sites can significantly influence the quenching of these minor proteins, particularly when zeaxanthin or lutein is used. The absence of Chl612 in CP24 and of Chl612 or Chl603 in CP29 has a considerably smaller effect on [Formula: see text] and [Formula: see text] than the influence of some carotenoids reported above. However, in CP29 our results indicate slightly dequenching and decreased [Formula: see text] when these chlorophylls are absent. This might indicate that both, Chl612 and Chl603 are involved in carotenoid-dependent quenching in isolated CP29.
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Affiliation(s)
- Daniel A Gacek
- Department for Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstr. 17, 38106, Brunswick, Germany
| | - Christoph-Peter Holleboom
- Department for Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstr. 17, 38106, Brunswick, Germany
| | - Pen-Nan Liao
- Department for Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstr. 17, 38106, Brunswick, Germany
| | - Marco Negretti
- Department of Physics and Astronomy and LaserLab Amsterdam, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy and LaserLab Amsterdam, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Peter Jomo Walla
- Department for Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstr. 17, 38106, Brunswick, Germany.
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6
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Gacek DA, Holleboom C, Tietz S, Kirchhoff H, Walla PJ. PsbS‐dependent and ‐independent mechanisms regulate carotenoid‐chlorophyll energy coupling in grana thylakoids. FEBS Lett 2019; 593:3190-3197. [DOI: 10.1002/1873-3468.13586] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/18/2019] [Accepted: 08/05/2019] [Indexed: 01/26/2023]
Affiliation(s)
- Daniel A. Gacek
- Department of Biophysical Chemistry Institute for Physical and Theoretical Chemistry Technische Universität Braunschweig Germany
| | - Christoph‐Peter Holleboom
- Department of Biophysical Chemistry Institute for Physical and Theoretical Chemistry Technische Universität Braunschweig Germany
| | - Stefanie Tietz
- Institute of Biological Chemistry Washington State University Pullman WA USA
- DOE Plant Research Laboratory Michigan State University East Lansing MI USA
| | - Helmut Kirchhoff
- Institute of Biological Chemistry Washington State University Pullman WA USA
| | - Peter Jomo Walla
- Department of Biophysical Chemistry Institute for Physical and Theoretical Chemistry Technische Universität Braunschweig Germany
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7
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Balevičius V, Fox KF, Bricker WP, Jurinovich S, Prandi IG, Mennucci B, Duffy CDP. Fine control of chlorophyll-carotenoid interactions defines the functionality of light-harvesting proteins in plants. Sci Rep 2017; 7:13956. [PMID: 29066753 PMCID: PMC5655323 DOI: 10.1038/s41598-017-13720-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 09/26/2017] [Indexed: 11/08/2022] Open
Abstract
Photosynthetic antenna proteins can be thought of as "programmed solvents", which bind pigments at specific mutual orientations, thus tuning the overall energetic landscape and ensuring highly efficient light-harvesting. While positioning of chlorophyll cofactors is well understood and rationalized by the principle of an "energy funnel", the carotenoids still pose many open questions. Particularly, their short excited state lifetime (<25 ps) renders them potential energy sinks able to compete with the reaction centers and drastically undermine light-harvesting efficiency. Exploration of the orientational phase-space revealed that the placement of central carotenoids minimizes their interaction with the nearest chlorophylls in the plant antenna complexes LHCII, CP26, CP29 and LHCI. At the same time we show that this interaction is highly sensitive to structural perturbations, which has a profound effect on the overall lifetime of the complex. This links the protein dynamics to the light-harvesting regulation in plants by the carotenoids.
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Affiliation(s)
- Vytautas Balevičius
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Kieran F Fox
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - William P Bricker
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Sandro Jurinovich
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, Pisa, 56124, Italy
| | - Ingrid G Prandi
- Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, Brazil
- Laboratory of Molecular Modeling Applied to the Chemical and Biological Defense, Military Institute of Engineering, Praça Gen, Tibúrcio, 80, Rio de Janeiro, Brazil
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, Pisa, 56124, Italy
| | - Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.
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8
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Gacek DA, Moore AL, Moore TA, Walla PJ. Two-Photon Spectra of Chlorophylls and Carotenoid–Tetrapyrrole Dyads. J Phys Chem B 2017; 121:10055-10063. [DOI: 10.1021/acs.jpcb.7b08502] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel A. Gacek
- Technische Universität Braunschweig, Institute for Physical and Theoretical Chemistry, Department of Biophysical
Chemistry, Gaußstraße.
17, 38106 Braunschweig, Germany
| | - Ana L. Moore
- School
of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Thomas A. Moore
- School
of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Peter Jomo Walla
- Technische Universität Braunschweig, Institute for Physical and Theoretical Chemistry, Department of Biophysical
Chemistry, Gaußstraße.
17, 38106 Braunschweig, Germany
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9
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Holleboom CP, Gacek DA, Liao PN, Negretti M, Croce R, Walla PJ. Carotenoid-chlorophyll coupling and fluorescence quenching in aggregated minor PSII proteins CP24 and CP29. PHOTOSYNTHESIS RESEARCH 2015; 124:171-180. [PMID: 25744389 DOI: 10.1007/s11120-015-0113-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/25/2015] [Indexed: 05/28/2023]
Abstract
It is known that aggregation of isolated light-harvesting complex II (LHCII) in solution results in high fluorescence quenching, reduced chlorophyll fluorescence lifetime, and increased electronic coupling of carotenoid (Car) S1 and chlorophyll (Chl) Qy states, as determined by two-photon studies. It has been suggested that this behavior of aggregated LHCII mimics aspects of non-photochemical quenching processes of higher plants and algae. However, several studies proposed that the minor photosystem II proteins CP24 and CP29 also play a significant role in regulation of photosynthesis. Therefore, we use a simple protocol that allows gradual aggregation also of CP24 and CP29. Similarly, as observed for LHCII, aggregation of CP24 and CP29 also leads to increasing fluorescence quenching and increasing electronic Car S1-Chl Qy coupling. Furthermore, a direct comparison of the three proteins revealed a significant higher electronic coupling in the two minor proteins already in the absence of any aggregation. These differences become even more prominent upon aggregation. A red-shift of the Qy absorption band known from LHCII aggregation was also observed for CP29 but not for CP24. We discuss possible implications of these results for the role of CP24 and CP29 as potential valves for excess excitation energy in the regulation of photosynthetic light harvesting.
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Affiliation(s)
- Christoph-Peter Holleboom
- Department for Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, Technische Universität Braunschweig, Hans-Sommer-Str. 10, 38106, Braunschweig, Germany
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10
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Krüger TP, Ilioaia C, Johnson MP, Ruban AV, van Grondelle R. Disentangling the low-energy states of the major light-harvesting complex of plants and their role in photoprotection. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1027-38. [DOI: 10.1016/j.bbabio.2014.02.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 11/28/2022]
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11
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Krüger TPJ, Ilioaia C, Johnson MP, Belgio E, Horton P, Ruban AV, van Grondelle R. The specificity of controlled protein disorder in the photoprotection of plants. Biophys J 2014; 105:1018-26. [PMID: 23972853 DOI: 10.1016/j.bpj.2013.07.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 06/11/2013] [Accepted: 07/15/2013] [Indexed: 11/28/2022] Open
Abstract
Light-harvesting pigment-protein complexes of photosystem II of plants have a dual function: they efficiently use absorbed energy for photosynthesis at limiting sunlight intensity and dissipate the excess energy at saturating intensity for photoprotection. Recent single-molecule spectroscopy studies on the trimeric LHCII complex showed that environmental control of the intrinsic protein disorder could in principle explain the switch between their light-harvesting and photoprotective conformations in vivo. However, the validity of this proposal depends strongly on the specificity of the protein dynamics. Here, a similar study has been performed on the minor monomeric antenna complexes of photosystem II (CP29, CP26, and CP24). Despite their high structural homology, similar pigment content and organization compared to LHCII trimers, the environmental response of these proteins was found to be rather distinct. A much larger proportion of the minor antenna complexes were present in permanently weakly fluorescent states under most conditions used; however, unlike LHCII trimers the distribution of the single-molecule population between the strongly and weakly fluorescent states showed no significant sensitivity to low pH, zeaxanthin, or low detergent conditions. The results support a unique role for LHCII trimers in the regulation of light harvesting by controlled fluorescence blinking and suggest that any contribution of the minor antenna complexes to photoprotection would probably involve a distinct mechanism.
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Affiliation(s)
- Tjaart P J Krüger
- Department of Physics and Astronomy, VU University Amsterdam, Amsterdam, The Netherlands.
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12
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How Protein Disorder Controls Non-Photochemical Fluorescence Quenching. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2014. [DOI: 10.1007/978-94-017-9032-1_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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13
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Sunku K, de Groot HJM, Pandit A. Insights into the photoprotective switch of the major light-harvesting complex II (LHCII): a preserved core of arginine-glutamate interlocked helices complemented by adjustable loops. J Biol Chem 2013; 288:19796-804. [PMID: 23629658 DOI: 10.1074/jbc.m113.456111] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Light-harvesting antennae of the LHC family form transmembrane three-helix bundles of which two helices are interlocked by conserved arginine-glutamate (Arg-Glu) ion pairs that form ligation sites for chlorophylls. The antenna proteins of photosystem II have an intriguing dual function. In excess light, they can switch their conformation from a light-harvesting into a photoprotective state, in which the excess and harmful excitation energies are safely dissipated as heat. Here we applied magic angle spinning NMR and selective Arg isotope enrichment as a noninvasive method to analyze the Arg structures of the major light-harvesting complex II (LHCII). The conformations of the Arg residues that interlock helix A and B appear to be preserved in the light-harvesting and photoprotective state. Several Arg residues have very downfield-shifted proton NMR responses, indicating that they stabilize the complex by strong hydrogen bonds. For the Arg Cα chemical shifts, differences are observed between LHCII in the active, light-harvesting and in the photoprotective, quenched state. These differences are attributed to a conformational change of the Arg residue in the stromal loop region. We conclude that the interlocked helices of LHCII form a rigid core. Consequently, the LHCII conformational switch does not involve changes in A/B helix tilting but likely involves rearrangements of the loops and helical segments close to the stromal and lumenal ends.
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Affiliation(s)
- Kiran Sunku
- Department of Solid-State NMR, Leiden Institute of Chemistry, Gorlaeus Laboratory, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
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14
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Pandit A, Reus M, Morosinotto T, Bassi R, Holzwarth AR, de Groot HJM. An NMR comparison of the light-harvesting complex II (LHCII) in active and photoprotective states reveals subtle changes in the chlorophyll a ground-state electronic structures. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:738-44. [PMID: 23466337 DOI: 10.1016/j.bbabio.2013.02.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/14/2013] [Accepted: 02/23/2013] [Indexed: 11/15/2022]
Abstract
To protect the photosynthetic apparatus against photo-damage in high sunlight, the photosynthetic antenna of oxygenic organisms can switch from a light-harvesting to a photoprotective mode through the process of non-photochemical quenching (NPQ). There is growing evidence that light-harvesting proteins of photosystem II participate in photoprotection by a built-in capacity to switch their conformation between light-harvesting and energy-dissipating states. Here we applied high-resolution Magic-Angle Spinning Nuclear Magnetic Resonance on uniformly (13)C-enriched major light-harvesting complex II (LHCII) of Chlamydomonas reinhardtii in active or quenched states. Our results reveal that the switch into a dissipative state is accompanied by subtle changes in the chlorophyll (Chl) a ground-state electronic structures that affect their NMR responses, particularly for the macrocycle (13)C4, (13)C5 and (13)C6 carbon atoms. Inspection of the LHCII X-ray structures shows that of the Chl molecules in the terminal emitter domain, where excited-state energy accumulates prior to further transfer or dissipation, the C4, 5 and 6 atoms are in closest proximity to lutein; supporting quenching mechanisms that involve altered Chl-lutein interactions in the dissipative state. In addition the observed changes could represent altered interactions between Chla and neoxanthin, which alters its configuration under NPQ conditions. The Chls appear to have increased dynamics in unquenched, detergent-solubilized LHCII. Our work demonstrates that solid-state Nuclear Magnetic Resonance is applicable to investigate high-resolution structural details of light-harvesting proteins in varied functional conditions, and represents a valuable tool to address their molecular plasticity associated with photoprotection.
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Affiliation(s)
- Anjali Pandit
- Department of Physics and Astronomy, VU University Amsterdam, Amsterdam, The Netherlands.
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15
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Holleboom CP, Yoo S, Liao PN, Compton I, Haase W, Kirchhoff H, Walla PJ. Carotenoid–Chlorophyll Coupling and Fluorescence Quenching Correlate with Protein Packing Density in Grana-Thylakoids. J Phys Chem B 2013; 117:11022-30. [DOI: 10.1021/jp311786g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christoph-Peter Holleboom
- Institute of Physical and Theoretical
Chemistry, Department of Biophysical Chemistry, Technische Universität Braunschweig, Hans-Sommer-Straße
10, 38106 Braunschweig, Germany
| | - Sunny Yoo
- Sungkyunkwan University, Department of
Energy Science, Suwon 440-746, Korea
| | - Pen-Nan Liao
- Institute of Physical and Theoretical
Chemistry, Department of Biophysical Chemistry, Technische Universität Braunschweig, Hans-Sommer-Straße
10, 38106 Braunschweig, Germany
| | - Ian Compton
- Institute of Biological Chemistry, Washington State University, P.O. Box 646340, Pullman,
Washington 99164, United States
| | - Winfried Haase
- Department of Structural
Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, P.O. Box 646340, Pullman,
Washington 99164, United States
| | - Peter Jomo Walla
- Institute of Physical and Theoretical
Chemistry, Department of Biophysical Chemistry, Technische Universität Braunschweig, Hans-Sommer-Straße
10, 38106 Braunschweig, Germany
- AG Biomolecular Spectroscopy
and Single-Molecule Detection, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen,
Germany
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16
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König C, Schlüter N, Neugebauer J. Direct determination of exciton couplings from subsystem time-dependent density-functional theory within the Tamm–Dancoff approximation. J Chem Phys 2013; 138:034104. [DOI: 10.1063/1.4774117] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Pillai S, Ravensbergen J, Antoniuk-Pablant A, Sherman BD, van Grondelle R, Frese RN, Moore TA, Gust D, Moore AL, Kennis JTM. Carotenoids as electron or excited-state energy donors in artificial photosynthesis: an ultrafast investigation of a carotenoporphyrin and a carotenofullerene dyad. Phys Chem Chem Phys 2013; 15:4775-84. [DOI: 10.1039/c3cp50364j] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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