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Rankelytė G, Gelzinis A, Robert B, Valkunas L, Chmeliov J. Environment-dependent chlorophyll-chlorophyll charge transfer states in Lhca4 pigment-protein complex. FRONTIERS IN PLANT SCIENCE 2024; 15:1412750. [PMID: 39170787 PMCID: PMC11335733 DOI: 10.3389/fpls.2024.1412750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/02/2024] [Indexed: 08/23/2024]
Abstract
Photosystem I (PSI) light-harvesting antenna complexes LHCI contain spectral forms that absorb and emit photons of lower energy than that of its primary electron donor, P700. The most red-shifted fluorescence is associated with the Lhca4 complex. It has been suggested that this red emission is related to the inter-chlorophyll charge transfer (CT) states. In this work we present a systematic quantum-chemical study of the CT states in Lhca4, accounting for the influence of the protein environment by estimating the electrostatic interactions. We show that significant energy shifts result from these interactions and propose that the emission of the Lhca4 complex is related not only to the previously proposed a603+-a608- state, but also to the a602+-a603- state. We also investigate how different protonation patterns of protein amino acids affect the energetics of the CT states.
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Affiliation(s)
- Gabrielė Rankelytė
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Andrius Gelzinis
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Bruno Robert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Leonas Valkunas
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Jevgenij Chmeliov
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
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Gelzinis A, Chmeliov J, Tutkus M, Vitulskienė E, Franckevičius M, Büchel C, Robert B, Valkunas L. Fluorescence quenching in aggregates of fucoxanthin-chlorophyll protein complexes: Interplay of fluorescing and dark states. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149030. [PMID: 38163538 DOI: 10.1016/j.bbabio.2023.149030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/29/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
Diatoms, a major group of algae, account for about a quarter of the global primary production on Earth. These photosynthetic organisms face significant challenges due to light intensity variations in their underwater habitat. To avoid photodamage, they have developed very efficient non-photochemical quenching (NPQ) mechanisms. These mechanisms originate in their light-harvesting antenna - the fucoxanthin-chlorophyll protein (FCP) complexes. Spectroscopic studies of NPQ in vivo are often hindered by strongly overlapping signals from the photosystems and their antennae. Fortunately, in vitro FCP aggregates constitute a useful model system to study fluorescence (FL) quenching in diatoms. In this work, we present streak-camera FL measurements on FCPa and FCPb complexes, isolated from a centric diatom Cyclotella meneghiniana, and their aggregates. We find that spectra of non-aggregated FCP are dominated by a single fluorescing species, but the FL spectra of FCP aggregates additionally contain contributions from a redshifted emissive state. We relate this red state to a charge transfer state between chlorophyll c and chlorophyll a molecules. The FL quenching, on the other hand, is due to an additional dark state that involves incoherent energy transfer to the fucoxanthin carotenoids. Overall, the global picture of energy transfer and quenching in FCP aggregates is very similar to that of major light-harvesting complexes in higher plants (LHCII), but microscopic details between FCPs and LHCIIs differ significantly.
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Affiliation(s)
- Andrius Gelzinis
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, 10257 Vilnius, Lithuania; Institute of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9-III, 10222 Vilnius, Lithuania
| | - Jevgenij Chmeliov
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, 10257 Vilnius, Lithuania; Institute of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9-III, 10222 Vilnius, Lithuania
| | - Marijonas Tutkus
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, 10257 Vilnius, Lithuania; Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio Ave. 7, 10257 Vilnius, Lithuania
| | - Ernesta Vitulskienė
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, 10257 Vilnius, Lithuania
| | - Marius Franckevičius
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, 10257 Vilnius, Lithuania
| | - Claudia Büchel
- Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt, Germany
| | - Bruno Robert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Leonas Valkunas
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, 10257 Vilnius, Lithuania; Institute of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9-III, 10222 Vilnius, Lithuania.
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Marcolin G, Tumbarello F, Fresch E, Agostini A, Büchel C, Carbonera D, Collini E. Two-Dimensional Electronic Spectroscopy Characterization of Fucoxanthin-Chlorophyll Protein Reveals Excitonic Carotenoid-Chlorophyll Interactions. J Phys Chem Lett 2024; 15:2392-2399. [PMID: 38394035 DOI: 10.1021/acs.jpclett.3c03609] [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: 02/25/2024]
Abstract
Fucoxanthin Chlorophyll Protein (FCP) is a Light Harvesting Complex found in diatoms and brown algae. It is particularly interesting for its efficiency in capturing the blue-green part of the light spectrum due to the presence of specific chromophores (fucoxanthin, chlorophyll a, and chlorophyll c). Recently, the crystallographic structure of FCP was solved, revealing the 3D arrangement of the pigments in the protein scaffold. While this information is helpful for interpreting the spectroscopic features of FCP, it has also raised new questions about the potential interactions between fucoxanthin and chlorophyll c. These interactions were suggested by their spatial closeness but have never been experimentally observed. To investigate this possible interaction mechanism, in this work, two-dimensional electronic spectroscopy (2DES) has been applied to study the ultrafast relaxation dynamics of FCP. The experiments captured an instantaneous delocalization of the excitation among fucoxanthin and chlorophyll c, suggesting the presence of a non-negligible coupling between the chromophores.
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Affiliation(s)
- Giampaolo Marcolin
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Francesco Tumbarello
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Elisa Fresch
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Alessandro Agostini
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Claudia Büchel
- Institut für Molekulare Biowissenschaften, Goethe Universität Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt, Germany
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Elisabetta Collini
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
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Maity S, Daskalakis V, Jansen TLC, Kleinekathöfer U. Electric Field Susceptibility of Chlorophyll c Leads to Unexpected Excitation Dynamics in the Major Light-Harvesting Complex of Diatoms. J Phys Chem Lett 2024; 15:2499-2510. [PMID: 38410961 PMCID: PMC10926154 DOI: 10.1021/acs.jpclett.3c03241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/04/2024] [Accepted: 02/12/2024] [Indexed: 02/28/2024]
Abstract
Diatoms are one of the most abundant photosynthetic organisms on earth and contribute largely to atmospheric oxygen production. They contain fucoxanthin and chlorophyll-a/c binding proteins (FCPs) as light-harvesting complexes with a remarkable adaptation to the fluctuating light on ocean surfaces. To understand the basis of the photosynthetic process in diatoms, the excitation energy funneling within FCPs must be probed. A state-of-the-art multiscale analysis within a quantum mechanics/molecular mechanics framework has been employed. To this end, the chlorophyll (Chl) excitation energies within the FCP complex from the diatom Phaeodactylum tricornutum have been determined. The Chl-c excitation energies were found to be 5-fold more susceptible to electric fields than those of Chl-a pigments and thus are significantly lower in FCP than in organic solvents. This finding challenges the general belief that the excitation energy of Chl-c is always higher than that of Chl-a in FCP proteins and reveals that Chl-c molecules are much more sensitive to electric fields within protein scaffolds than in Chl-a pigments. The analysis of the linear absorption spectrum and the two-dimensional electronic spectra of the FCP complex strongly supports these findings and allows us to study the excitation transfer within the FCP complex.
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Affiliation(s)
- Sayan Maity
- School
of Science, Constructor University, Campus Ring 1, 28759 Bremen, Germany
| | - Vangelis Daskalakis
- Department
of Chemical Engineering, School of Engineering,
University of Patras, Patras 26504, Greece
| | - Thomas L. C. Jansen
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
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Agostini A, Bína D, Carbonera D, Litvín R. Conservation of triplet-triplet energy transfer photoprotective pathways in fucoxanthin chlorophyll-binding proteins across algal lineages. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148935. [PMID: 36379269 DOI: 10.1016/j.bbabio.2022.148935] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/18/2022] [Accepted: 11/07/2022] [Indexed: 11/14/2022]
Abstract
Detailed information on the photo-generated triplet states of diatom and haptophyte Fucoxanthin Chlorophyll-binding Proteins (FCPs and E-FCPs, respectively) have been obtained from a combined spectroscopic investigation involving Transient Absorption and Time-Resolved Electron Paramagnetic Resonance. Pennate diatom Phaeodactylum tricornutum FCP shows identical photoprotective Triplet-Triplet Energy Transfer (TTET) pathways to the previously investigated centric diatom Cyclotella meneghiniana FCP, with the same two chlorophyll a-fucoxanthin pairs that involve the fucoxanthins in sites Fx301 and Fx302 contributing to TTET in both diatom groups. In the case of the haptophyte Emilianina huxleyi E-FCP, only one of the two chlorophyll a-fucoxanthins pairs observed in diatoms, the one involving chlorophyll a409 and Fx301, has been shown to be active in TTET. Furthermore, despite the marked change in the pigment content of E-FCP with growth light intensity, the TTET pathway is not affected. Thus, our comparative investigation of FCPs revealed a photoprotective TTET pathway shared within these classes involving the fucoxanthin in site Fx301, a site exposed to the exterior of the antenna monomer that has no equivalent in Light-Harvesting Complexes from the green lineage.
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Affiliation(s)
- Alessandro Agostini
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 1160/31, 370 05 České Budějovice, Czech Republic.
| | - David Bína
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 1160/31, 370 05 České Budějovice, Czech Republic; Institute of Chemistry, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
| | - Radek Litvín
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 1160/31, 370 05 České Budějovice, Czech Republic; Institute of Chemistry, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.
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Zakutauskaitė K, Mačernis M, Nguyen HH, Ogilvie JP, Abramavičius D. Extracting the excitonic Hamiltonian of a chlorophyll dimer from broadband two-dimensional electronic spectroscopy. J Chem Phys 2023; 158:015103. [PMID: 36610982 DOI: 10.1063/5.0108166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We apply Frenkel exciton theory to model the entire Q-band of a tightly bound chlorophyll dimer inspired by the photosynthetic reaction center of photosystem II. The potential of broadband two-dimensional electronic spectroscopy experiment spanning the Qx and Qy regions to extract the parameters of the model dimer Hamiltonian is examined through theoretical simulations of the experiment. We find that the local nature of Qx excitation enables identification of molecular properties of the delocalized Qy excitons. Specifically, we demonstrate that the cross-peak region, where excitation energy is resonant with Qy while detection is at Qx, contains specific spectral signatures that can reveal the full real-space molecular Hamiltonian, a task that is impossible by considering the Qy transitions alone. System-bath coupling and site energy disorder in realistic systems may limit the resolution of these spectral signatures due to spectral congestion.
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Affiliation(s)
- Kristina Zakutauskaitė
- Institute of Chemical Physics, Vilnius University, Sauletekio al. 9-III, Vilnius, Lithuania
| | - Mindaugas Mačernis
- Institute of Chemical Physics, Vilnius University, Sauletekio al. 9-III, Vilnius, Lithuania
| | - Hoang H Nguyen
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Jennifer P Ogilvie
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Darius Abramavičius
- Institute of Chemical Physics, Vilnius University, Sauletekio al. 9-III, Vilnius, Lithuania
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