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Bhattacharjee S, Arra S, Daidone I, Pantazis DA. Excitation landscape of the CP43 photosynthetic antenna complex from multiscale simulations. Chem Sci 2024; 15:7269-7284. [PMID: 38756808 PMCID: PMC11095388 DOI: 10.1039/d3sc06714a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/07/2024] [Indexed: 05/18/2024] Open
Abstract
Photosystem II (PSII), the principal enzyme of oxygenic photosynthesis, contains two integral light harvesting proteins (CP43 and CP47) that bind chlorophylls and carotenoids. The two intrinsic antennae play crucial roles in excitation energy transfer and photoprotection. CP43 interacts most closely with the reaction center of PSII, specifically with the branch of the reaction center (D1) that is responsible for primary charge separation and electron transfer. Deciphering the function of CP43 requires detailed atomic-level insights into the properties of the embedded pigments. To advance this goal, we employ a range of multiscale computational approaches to determine the site energies and excitonic profile of CP43 chlorophylls, using large all-atom models of a membrane-bound PSII monomer. In addition to time-dependent density functional theory (TD-DFT) used in the context of a quantum-mechanics/molecular-mechanics setup (QM/MM), we present a thorough analysis using the perturbed matrix method (PMM), which enables us to utilize information from long-timescale molecular dynamics simulations of native PSII-complexed CP43. The excited state energetics and excitonic couplings have both similarities and differences compared with previous experimental fits and theoretical calculations. Both static TD-DFT and dynamic PMM results indicate a layered distribution of site energies and reveal specific groups of chlorophylls that have shared contributions to low-energy excitations. Importantly, the contribution to the lowest energy exciton does not arise from the same chlorophylls at each system configuration, but rather changes as a function of conformational dynamics. An unexpected finding is the identification of a low-energy charge-transfer excited state within CP43 that involves a lumenal (C2) and the central (C10) chlorophyll of the complex. The results provide a refined basis for structure-based interpretation of spectroscopic observations and for further deciphering excitation energy transfer in oxygenic photosynthesis.
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Affiliation(s)
- Sinjini Bhattacharjee
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Srilatha Arra
- Department of Physical and Chemical Sciences, University of L'Aquila Via Vetoio (Coppito 1) 67010 L'Aquila Italy
| | - Isabella Daidone
- Department of Physical and Chemical Sciences, University of L'Aquila Via Vetoio (Coppito 1) 67010 L'Aquila Italy
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
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2
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Biswas S, Niedzwiedzki DM, Liberton M, Pakrasi HB. Phylogenetic and spectroscopic insights on the evolution of core antenna proteins in cyanobacteria. PHOTOSYNTHESIS RESEARCH 2023:10.1007/s11120-023-01046-6. [PMID: 37737529 DOI: 10.1007/s11120-023-01046-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 08/31/2023] [Indexed: 09/23/2023]
Abstract
Light harvesting by antenna systems is the initial step in a series of electron-transfer reactions in all photosynthetic organisms, leading to energy trapping by reaction center proteins. Cyanobacteria are an ecologically diverse group and are the simplest organisms capable of oxygenic photosynthesis. The primary light-harvesting antenna in cyanobacteria is the large membrane extrinsic pigment-protein complex called the phycobilisome. In addition, cyanobacteria have also evolved specialized membrane-intrinsic chlorophyll-binding antenna proteins that transfer excitation energy to the reaction centers of photosystems I and II (PSI and PSII) and dissipate excess energy through nonphotochemical quenching. Primary among these are the CP43 and CP47 proteins of PSII, but in addition, some cyanobacteria also use IsiA and the prochlorophyte chlorophyll a/b binding (Pcb) family of proteins. Together, these proteins comprise the CP43 family of proteins owing to their sequence similarity with CP43. In this article, we have revisited the evolution of these chlorophyll-binding antenna proteins by examining their protein sequences in parallel with their spectral properties. Our phylogenetic and spectroscopic analyses support the idea of a common ancestor for CP43, IsiA, and Pcb proteins, and suggest that PcbC might be a distant ancestor of IsiA. The similar spectral properties of CP47 and IsiA suggest a closer evolutionary relationship between these proteins compared to CP43.
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Affiliation(s)
- Sandeep Biswas
- Department of Biology, Washington University, St. Louis, MO, 63130, USA
| | - Dariusz M Niedzwiedzki
- Center for Solar Energy and Energy Storage, Washington University, St. Louis, MO, 63130, USA
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, 63130, USA
| | - Michelle Liberton
- Department of Biology, Washington University, St. Louis, MO, 63130, USA
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO, 63130, USA.
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3
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Biswas S, Niedzwiedzki DM, Pakrasi HB. Energy dissipation efficiency in the CP43 assembly intermediate complex of photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148982. [PMID: 37146928 DOI: 10.1016/j.bbabio.2023.148982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/10/2023] [Accepted: 04/20/2023] [Indexed: 05/07/2023]
Abstract
Photosystem II in oxygenic organisms is a large membrane bound rapidly turning over pigment protein complex. During its biogenesis, multiple assembly intermediates are formed, including the CP43-preassembly complex (pCP43). To understand the energy transfer dynamics in pCP43, we first engineered a His-tagged version of the CP43 in a CP47-less strain of the cyanobacterium Synechocystis 6803. Isolated pCP43 from this engineered strain was subjected to advanced spectroscopic analysis to evaluate its excitation energy dissipation characteristics. These included measurements of steady-state absorption and fluorescence emission spectra for which correlation was tested with Stepanov relation. Comparison of fluorescence excitation and absorptance spectra determined that efficiency of energy transfer from β-carotene to chlorophyll a is 39 %. Time-resolved fluorescence images of pCP43-bound Chl a were recorded on streak camera, and fluorescence decay dynamics were evaluated with global fitting. These demonstrated that the decay kinetics strongly depends on temperature and buffer used to disperse the protein sample and fluorescence decay lifetime was estimated in 3.2-5.7 ns time range, depending on conditions. The pCP43 complex was also investigated with femtosecond and nanosecond time-resolved absorption spectroscopy upon excitation of Chl a and β-carotene to reveal pathways of singlet excitation relaxation/decay, Chl a triplet dynamics and Chl a → β-carotene triplet state sensitization process. The latter demonstrated that Chl a triplet in the pCP43 complex is not efficiently quenched by carotenoids. Finally, detailed kinetic analysis of the rise of the population of β-carotene triplets determined that the time constant of the carotenoid triplet sensitization is 40 ns.
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Affiliation(s)
- Sandeep Biswas
- Department of Biology, Washington University, St. Louis, MO 63130, USA.
| | - Dariusz M Niedzwiedzki
- Center for Solar Energy and Energy Storage, Washington University, St. Louis, MO 63130, USA; Department of Energy, Environmental & Chemical Engineering, Washington University, St. Louis, MO 63130, USA.
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO 63130, USA.
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4
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Saito K, Mitsuhashi K, Tamura H, Ishikita H. Quantum mechanical analysis of excitation energy transfer couplings in photosystem II. Biophys J 2023; 122:470-483. [PMID: 36609140 PMCID: PMC9941724 DOI: 10.1016/j.bpj.2023.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/21/2022] [Accepted: 01/04/2023] [Indexed: 01/07/2023] Open
Abstract
We evaluated excitation energy transfer (EET) coupling (J) between all pairs of chlorophylls (Chls) and pheophytins (Pheos) in the protein environment of photosystem II based on the time-dependent density functional theory with a quantum mechanical/molecular mechanics approach. In the reaction center, the EET coupling between Chls PD1 and PD2 is weaker (|J(PD1/PD2)| = 79 cm-1), irrespective of a short edge-to-edge distance of 3.6 Å (Mg-to-Mg distance of 8.1 Å), than the couplings between PD1 and the accessory ChlD1 (|J(PD1/ChlD2)| = 104 cm-1) and between PD2 and ChlD2 (|J(PD2/ChlD1)| = 101 cm-1), suggesting that PD1 and PD2 are two monomeric Chls rather than a "special pair". There exist strongly coupled Chl pairs (|J| > ∼100 cm-1) in the CP47 and CP43 core antennas, which may be candidates for the red-shifted Chls observed in spectroscopic studies. In CP47 and CP43, Chls ligated to CP47-His26 and CP43-His56, which are located in the middle layer of the thylakoid membrane, play a role in the "hub" that mediates the EET from the lumenal to stromal layers. In the stromal layer, Chls ligated to CP47-His466, CP43-His441, and CP43-His444 mediate the EET from CP47 to ChlD2/PheoD2 and from CP43 to ChlD1/PheoD1 in the reaction center. Thus, the excitation energy from both CP47 and CP43 can always be utilized for the charge-separation reaction in the reaction center.
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Affiliation(s)
- Keisuke Saito
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo, Japan; Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan.
| | - Koji Mitsuhashi
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hiroyuki Tamura
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo, Japan; Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan.
| | - Hiroshi Ishikita
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo, Japan; Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan.
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5
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Sarngadharan P, Maity S, Kleinekathöfer U. Spectral densities and absorption spectra of the core antenna complex CP43 from photosystem II. J Chem Phys 2022; 156:215101. [DOI: 10.1063/5.0091005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Besides absorbing light, the core antenna complex CP43 of photosystem II is of great importance in transferring excitation energy from the antenna complexes to the reaction center. Excitation energies, spectral densities, and linear absorption spectra of the complex have been evaluated by a multiscale approach. In this scheme, quantum mechanics/molecular mechanics molecular dynamics simulations are performed employing the parameterized density functional tight binding (DFTB) while the time-dependent long-range-corrected DFTB scheme is applied for the excited state calculations. The obtained average spectral density of the CP43 complex shows a very good agreement with experimental results. Moreover, the excitonic Hamiltonian of the system along with the computed site-dependent spectral densities was used to determine the linear absorption. While a Redfield-like approximation has severe shortcomings in dealing with the CP43 complex due to quasi-degenerate states, the non-Markovian full second-order cumulant expansion formalism is able to overcome the drawbacks. Linear absorption spectra were obtained, which show a good agreement with the experimental counterparts at different temperatures. This study once more emphasizes that by combining diverse techniques from the areas of molecular dynamics simulations, quantum chemistry, and open quantum systems, it is possible to obtain first-principle results for photosynthetic complexes, which are in accord with experimental findings.
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Affiliation(s)
- Pooja Sarngadharan
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Sayan Maity
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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6
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Trempe A, Levenberg A, Ortega ADG, Lujan MA, Picorel R, Zazubovich V. Effects of Chlorophyll Triplet States on the Kinetics of Spectral Hole Growth. J Phys Chem B 2021; 125:3278-3285. [PMID: 33764072 DOI: 10.1021/acs.jpcb.0c09042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Spectral hole burning has been employed for decades to study various amorphous solids and proteins. Triplet states and respective transient holes were incorporated into theoretical models and software simulating nonphotochemical spectral hole burning (NPHB) and including all relevant distributions, in particular the distribution of the angle between the electric field of light E and transient dipole moment of the chromophore μ. The presence of a chlorophyll a triplet state with a lifetime of several milliseconds explains the slowdown of NPHB (on the depth vs illumination dose scale) with the increase of the light intensity, as well as larger hole depths observed in weak probe beam experiments, compared to those deduced from the hole growth kinetics (HGK) measurements (signal collected at a fixed wavelength while a stronger burning beam is on) in cytochrome b6f and chemically modified LH2. We also considered the solvent deuteration effects on triplet lifetime and concluded that both triplet states and local heating likely play a role in slowing down the HGK with increasing burn intensity.
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Affiliation(s)
- Alexandra Trempe
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal, Quebec H4B 1R6, Canada
| | - Alexander Levenberg
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal, Quebec H4B 1R6, Canada
| | | | - Maria A Lujan
- Estacion Experimental de Aula Dei (CSIC), Avda. Montañana 1005, Zaragoza 50059, Spain
| | - Rafael Picorel
- Estacion Experimental de Aula Dei (CSIC), Avda. Montañana 1005, Zaragoza 50059, Spain
| | - Valter Zazubovich
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal, Quebec H4B 1R6, Canada
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7
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Müh F, Zouni A. Structural basis of light-harvesting in the photosystem II core complex. Protein Sci 2020; 29:1090-1119. [PMID: 32067287 PMCID: PMC7184784 DOI: 10.1002/pro.3841] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 12/20/2022]
Abstract
Photosystem II (PSII) is a membrane-spanning, multi-subunit pigment-protein complex responsible for the oxidation of water and the reduction of plastoquinone in oxygenic photosynthesis. In the present review, the recent explosive increase in available structural information about the PSII core complex based on X-ray crystallography and cryo-electron microscopy is described at a level of detail that is suitable for a future structure-based analysis of light-harvesting processes. This description includes a proposal for a consistent numbering scheme of protein-bound pigment cofactors across species. The structural survey is complemented by an overview of the state of affairs in structure-based modeling of excitation energy transfer in the PSII core complex with emphasis on electrostatic computations, optical properties of the reaction center, the assignment of long-wavelength chlorophylls, and energy trapping mechanisms.
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Affiliation(s)
- Frank Müh
- Department of Theoretical Biophysics, Institute for Theoretical Physics, Johannes Kepler University Linz, Linz, Austria
| | - Athina Zouni
- Humboldt-Universität zu Berlin, Institute for Biology, Biophysics of Photosynthesis, Berlin, Germany
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8
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Pieper J, Artene P, Rätsep M, Pajusalu M, Freiberg A. Evaluation of Electron–Phonon Coupling and Spectral Densities of Pigment–Protein Complexes by Line-Narrowed Optical Spectroscopy. J Phys Chem B 2018; 122:9289-9301. [DOI: 10.1021/acs.jpcb.8b05220] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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9
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Mohamed A, Nagao R, Noguchi T, Fukumura H, Shibata Y. Structure-Based Modeling of Fluorescence Kinetics of Photosystem II: Relation between Its Dimeric Form and Photoregulation. J Phys Chem B 2016; 120:365-76. [PMID: 26714062 DOI: 10.1021/acs.jpcb.5b09103] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A photosystem II-enriched membrane (PSII-em) consists of the PSII core complex (PSII-cc) which is surrounded by peripheral antenna complexes. PSII-cc consists of two core antenna (CP43 and CP47) and the reaction center (RC) complex. Time-resolved fluorescence spectra of a PSII-em were measured at 77 K. The data were globally analyzed with a new compartment model, which has a minimum number of compartments and is consistent with the structure of PSII-cc. The reliability of the model was investigated by fitting the data of different experimental conditions. From the analysis, the energy-transfer time constants from the peripheral antenna to CP47 and CP43 were estimated to be 20 and 35 ps, respectively. With an exponential time constant of 320 ps, the excitation energy was estimated to accumulate in the reddest chlorophyll (Red Chl), giving a 692 nm fluorescence peak. The excited state on the Red Chl was confirmed to be quenched upon the addition of an oxidant, as reported previously. The calculations based on the Förster theory predicted that the excitation energy on Chl29 is quenched by ChlZD1(+), which is a redox active but not involved in the electron-transfer chain, located in the D1 subunit of RC, in the other monomer with an exponential time constant of 75 ps. This quenching pathway is consistent with our structure-based simulation of PSII-cc, which assigned Chl29 as the Red Chl. On the other hand, the alternative interpretation assigning Chl26 as the Red Chl was not excluded. The excited Chl26 was predicted to be quenched by another redox active ChlZD2(+) in the D2 subunit of RC in the same monomer unit with an exponential time constant of 88 ps.
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Affiliation(s)
- Ahmed Mohamed
- Department of Chemistry, Graduate School of Science, Tohoku University , Aramaki Aza Aoba, Aoba-Ku, Sendai 980-8578, Japan
| | - Ryo Nagao
- Division of Material Science (Physics), Graduate School of Science, Nagoya University , Furo-Cho, Chikusa-Ku, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- Division of Material Science (Physics), Graduate School of Science, Nagoya University , Furo-Cho, Chikusa-Ku, Nagoya 464-8602, Japan
| | - Hiroshi Fukumura
- Department of Chemistry, Graduate School of Science, Tohoku University , Aramaki Aza Aoba, Aoba-Ku, Sendai 980-8578, Japan
| | - Yutaka Shibata
- Department of Chemistry, Graduate School of Science, Tohoku University , Aramaki Aza Aoba, Aoba-Ku, Sendai 980-8578, Japan
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10
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The quest for energy traps in the CP43 antenna of photosystem II. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 152:286-300. [DOI: 10.1016/j.jphotobiol.2015.05.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/13/2015] [Accepted: 05/28/2015] [Indexed: 01/08/2023]
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11
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Hall J, Renger T, Picorel R, Krausz E. Circularly polarized luminescence spectroscopy reveals low-energy excited states and dynamic localization of vibronic transitions in CP43. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:115-128. [PMID: 26449206 DOI: 10.1016/j.bbabio.2015.09.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 09/23/2015] [Accepted: 09/29/2015] [Indexed: 11/26/2022]
Abstract
Circularly polarized luminescence (CPL) spectroscopy is an established but relatively little-used technique that monitors the chirality of an emission. When applied to photosynthetic pigment assemblies, we find that CPL provides sensitive and detailed information on low-energy exciton states, reflecting the interactions, site energies and geometries of interacting pigments. CPL is the emission analog of circular dichroism (CD) and thus spectra explore the optical activity only of fluorescent states of the pigment-protein complex and consequently the nature of the lowest-energy excited states (trap states), whose study is a critical area of photosynthesis research. In this work, we develop the new approach of temperature-dependent CPL spectroscopy, over the 2-120 K temperature range, and apply it to the CP43 proximal antenna protein of photosystem II. Our results confirm strong excitonic interactions for at least one of the two well-established emitting states of CP43 named "A" and "B". Previous structure-based models of CP43 spectra are evaluated in the light of the new CPL data. Our analysis supports the assignments of Shibata et al. [Shibata et al. J. Am. Chem. Soc. 135 (2013) 6903-6914], particularly for the highly-delocalized B-state. This state dominates CPL spectra and is attributed predominantly to chlorophyll a's labeled Chl 634 and Chl 636 (alternatively labeled Chl 43 and 45 by Shibata et al.). The absence of any CPL intensity in intramolecular vibrational sidebands associated with the delocalized "B" excited state is attributed to the dynamic localization of intramolecular vibronic transitions.
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Affiliation(s)
- Jeremy Hall
- Research School of Chemistry, Australian National University, Canberra, Australia
| | - Thomas Renger
- Institut für Theoretische Physik, Johannes Kepler Universität, Linz, Austria
| | - Rafael Picorel
- Estacion Experimental de Aula Dei (CSIC), Avda. Montañana, Zaragoza, Spain
| | - Elmars Krausz
- Research School of Chemistry, Australian National University, Canberra, Australia.
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12
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Najafi M, Zazubovich V. Monte Carlo Modeling of Spectral Diffusion Employing Multiwell Protein Energy Landscapes: Application to Pigment-Protein Complexes Involved in Photosynthesis. J Phys Chem B 2015; 119:7911-21. [PMID: 26020801 DOI: 10.1021/acs.jpcb.5b02764] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We are reporting development and initial applications of the light-induced and thermally induced spectral diffusion modeling software, covering nonphotochemical spectral hole burning (NPHB), hole recovery, and single-molecule spectroscopy and involving random generation of the multiwell protein energy landscapes. The model includes tunneling and activated barrier-hopping in both ground and excited states of a protein-chromophore system. Evolution of such a system is predicted by solving the system of rate equations. Using the barrier parameters from the range typical for the energy landscapes of the pigment-protein complexes involved in photosynthesis, we (a) show that realistic cooling of the sample must result in proteins quite far from thermodynamic equilibrium, (b) demonstrate hole evolution in the cases of burning, fixed-temperature recovery and thermocycling that mostly agrees with the experiment and modeling based on the NPHB master equation, and (c) explore the effects of different protein energy landscapes on the antihole shape. Introducing the multiwell energy landscapes and starting the hole burning experiments in realistic nonequilibrium conditions are not sufficient to explain all experimental observations even qualitatively. Therefore, for instance, one is required to invoke the modified NPHB mechanism where a complex interplay of several small conformational changes is poising the energy landscape of the pigment-protein system for downhill tunneling.
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Affiliation(s)
- Mehdi Najafi
- Department of Physics, Concordia University, Montreal H4B 1R6, Quebec, Canada
| | - Valter Zazubovich
- Department of Physics, Concordia University, Montreal H4B 1R6, Quebec, Canada
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13
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Najafi M, Herascu N, Shafiei G, Picorel R, Zazubovich V. Conformational Changes in Pigment–Protein Complexes at Low Temperatures—Spectral Memory and a Possibility of Cooperative Effects. J Phys Chem B 2015; 119:6930-40. [PMID: 25985255 DOI: 10.1021/acs.jpcb.5b02845] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mehdi Najafi
- Department
of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Nicoleta Herascu
- Department
of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Golia Shafiei
- Department
of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Rafael Picorel
- Estacion Experimental de Aula Dei (CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain
| | - Valter Zazubovich
- Department
of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
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14
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15
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Zazubovich V. Fluorescence Line Narrowing and Δ-FLN Spectra in the Presence of Excitation Energy Transfer between Weakly Coupled Chromophores. J Phys Chem B 2014; 118:13535-43. [DOI: 10.1021/jp509056z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Valter Zazubovich
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal H4B 1R6, Quebec, Canada
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16
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Najafi M, Herascu N, Seibert M, Picorel R, Jankowiak R, Zazubovich V. Spectral Hole Burning, Recovery, and Thermocycling in Chlorophyll–Protein Complexes: Distributions of Barriers on the Protein Energy Landscape. J Phys Chem B 2012; 116:11780-90. [DOI: 10.1021/jp308055r] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mehdi Najafi
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal,
Quebec H4B 1R6 Canada
| | - Nicoleta Herascu
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal,
Quebec H4B 1R6 Canada
| | - Michael Seibert
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Rafael Picorel
- Estacion Experimental de Aula Dei (CSIC), Avda. Montañana 1005, 50002
Zaragoza, Spain
| | - Ryszard Jankowiak
- Department
of Chemistry, Kansas State University,
Manhattan, Kansas 66505, United
States
| | - Valter Zazubovich
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal,
Quebec H4B 1R6 Canada
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17
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Müh F, Madjet MEA, Renger T. Structure-based simulation of linear optical spectra of the CP43 core antenna of photosystem II. PHOTOSYNTHESIS RESEARCH 2012; 111:87-101. [PMID: 21809112 DOI: 10.1007/s11120-011-9675-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 07/18/2011] [Indexed: 05/31/2023]
Abstract
The linear optical spectra (absorbance, linear dichroism, circular dichroism, fluorescence) of the CP43 (PsbC) antenna of the photosystem II core complex (PSIIcc) pertaining to the S(0) → S(1) (Q(Y)) transitions of the chlorophyll (Chl) a pigments are simulated by applying a combined quantum chemical/electrostatic method to obtain excitonic couplings and local transition energies (site energies) on the basis of the 2.9 Å resolution crystal structure (Guskov et al., Nat Struct Mol Biol 16:334-342, 2009). The electrostatic calculations identify three Chls with low site energies (Chls 35, 37, and 45 in the nomenclature of Loll et al. (Nature 438:1040-1044, 2005). A refined simulation of experimental spectra of isolated CP43 suggests a modified set of site energies within 143 cm(-1) of the directly calculated values (root mean square deviation: 80 cm(-1)). In the refined set, energy sinks are at Chls 37, 43, and 45 in agreement with earlier fitting results (Raszewski and Renger, J Am Chem Soc 130:4431-4446, 2008). The present structure-based simulations reveal that a large part of the redshift of Chl 37 is due to a digalactosyldiacylglycerol lipid. This finding suggests a new role for lipids in PSIIcc, namely the tuning of optical spectra and the creation of an excitation energy funnel towards the reaction center. The analysis of electrostatic pigment-protein interactions is used to identify amino acid residues that are of potential interest for an experimental approach to an assignment of site energies and energy sinks by site-directed mutagenesis.
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Affiliation(s)
- Frank Müh
- Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040, Linz, Austria.
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Herascu N, Ahmouda S, Picorel R, Seibert M, Jankowiak R, Zazubovich V. Effects of the Distributions of Energy or Charge Transfer Rates on Spectral Hole Burning in Pigment–Protein Complexes at Low Temperatures. J Phys Chem B 2011; 115:15098-109. [DOI: 10.1021/jp208142k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nicoleta Herascu
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6 Canada
| | - Somaya Ahmouda
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6 Canada
| | - Rafael Picorel
- Estacion Experimental Aula Dei (CSIC), Avda. Montañana, 50059 Zaragoza, Spain
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Michael Seibert
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Valter Zazubovich
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6 Canada
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Feng X, Neupane B, Acharya K, Zazubovich V, Picorel R, Seibert M, Jankowiak R. Spectroscopic Study of the CP43′ Complex and the PSI–CP43′ Supercomplex of the Cyanobacterium Synechocystis PCC 6803. J Phys Chem B 2011; 115:13339-49. [DOI: 10.1021/jp206054b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ximao Feng
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Bhanu Neupane
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Khem Acharya
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Valter Zazubovich
- Department of Physics, Concordia University, Montreal, Quebec, Canada
| | - Rafael Picorel
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Estación Experimental de Aula Dei (CSIC), Zaragoza, Spain
| | - Michael Seibert
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
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Renger T, Schlodder E. Optical properties, excitation energy and primary charge transfer in photosystem II: theory meets experiment. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:126-41. [PMID: 21531572 DOI: 10.1016/j.jphotobiol.2011.03.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/04/2011] [Accepted: 03/21/2011] [Indexed: 11/29/2022]
Abstract
In this review we discuss structure-function relationships of the core complex of photosystem II, as uncovered from analysis of optical spectra of the complex and its subunits. Based on descriptions of optical difference spectra including site directed mutagenesis we propose a revision of the multimer model of the symmetrically arranged reaction center pigments, described by an asymmetric exciton Hamiltonian. Evidence is provided for the location of the triplet state, the identity of the primary electron donor, the localization of the cation and the secondary electron transfer pathway in the reaction center. We also discuss the stationary and time-dependent optical properties of the CP43 and CP47 subunits and the excitation energy transfer and trapping-by-charge-transfer kinetics in the core complex.
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Affiliation(s)
- Thomas Renger
- Institut für Theoretische Physik, Johannes Kepler Universität, Abteilung Theoretische Biophysik, Austria.
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Herascu N, Najafi M, Amunts A, Pieper J, Irrgang KD, Picorel R, Seibert M, Zazubovich V. Parameters of the protein energy landscapes of several light-harvesting complexes probed via spectral hole growth kinetics measurements. J Phys Chem B 2011; 115:2737-47. [PMID: 21391534 DOI: 10.1021/jp108775y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The parameters of barrier distributions on the protein energy landscape in the excited electronic state of the pigment/protein system have been determined by means of spectral hole burning for the lowest-energy pigments of CP43 core antenna complex and CP29 minor antenna complex of spinach Photosystem II (PS II) as well as of trimeric and monomeric LHCII complexes transiently associated with the pea Photosystem I (PS I) pool. All of these complexes exhibit sixty to several hundred times lower spectral hole burning yields as compared with molecular glassy solids previously probed by means of the hole growth kinetics measurements. Therefore, the entities (groups of atoms), which participate in conformational changes in protein, appear to be significantly larger and heavier than those in molecular glasses. No evidence of a small (∼1 cm(-1)) spectral shift tier of the spectral diffusion dynamics has been observed. Therefore, our data most likely reflect the true barrier distributions of the intact protein and not those related to the interface or surrounding host. Possible applications of the barrier distributions as well as the assignments of low-energy states of CP29 and LHCII are discussed in light of the above results.
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Affiliation(s)
- Nicoleta Herascu
- Department of Physics, Concordia University, Montreal, Quebec, Canada
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Energy transfer processes in the isolated core antenna complexes CP43 and CP47 of photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1606-16. [DOI: 10.1016/j.bbabio.2010.05.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 05/07/2010] [Accepted: 05/11/2010] [Indexed: 11/21/2022]
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Renger T, Schlodder E. Primary Photophysical Processes in Photosystem II: Bridging the Gap between Crystal Structure and Optical Spectra. Chemphyschem 2010; 11:1141-53. [DOI: 10.1002/cphc.200900932] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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24
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Modeling study of non-line-narrowed hole-burned spectra in weakly coupled dimers and multi-chromophoric molecular assemblies. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2009.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Purchase R, Völker S. Spectral hole burning: examples from photosynthesis. PHOTOSYNTHESIS RESEARCH 2009; 101:245-66. [PMID: 19714478 PMCID: PMC2744831 DOI: 10.1007/s11120-009-9484-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Accepted: 07/31/2009] [Indexed: 05/14/2023]
Abstract
The optical spectra of photosynthetic pigment-protein complexes usually show broad absorption bands, often consisting of a number of overlapping, "hidden" bands belonging to different species. Spectral hole burning is an ideal technique to unravel the optical and dynamic properties of such hidden species. Here, the principles of spectral hole burning (HB) and the experimental set-up used in its continuous wave (CW) and time-resolved versions are described. Examples from photosynthesis studied with hole burning, obtained in our laboratory, are then presented. These examples have been classified into three groups according to the parameters that were measured: (1) hole widths as a function of temperature, (2) hole widths as a function of delay time and (3) hole depths as a function of wavelength. Two examples from light-harvesting (LH) 2 complexes of purple bacteria are given within the first group: (a) the determination of energy-transfer times from the chromophores in the B800 ring to the B850 ring, and (b) optical dephasing in the B850 absorption band. One example from photosystem II (PSII) sub-core complexes of higher plants is given within the second group: it shows that the size of the complex determines the amount of spectral diffusion measured. Within the third group, two examples from (green) plants and purple bacteria have been chosen for: (a) the identification of "traps" for energy transfer in PSII sub-core complexes of green plants, and (b) the uncovering of the lowest k = 0 exciton-state distribution within the B850 band of LH2 complexes of purple bacteria. The results prove the potential of spectral hole burning measurements for getting quantitative insight into dynamic processes in photosynthetic systems at low temperature, in particular, when individual bands are hidden within broad absorption bands. Because of its high-resolution wavelength selectivity, HB is a technique that is complementary to ultrafast pump-probe methods. In this review, we have provided an extensive bibliography for the benefit of scientists who plan to make use of this valuable technique in their future research.
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Affiliation(s)
- Robin Purchase
- Huygens and Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Silvia Völker
- Huygens and Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
- Department of Biophysics, Faculty of Exact Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
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Pieper J, Rätsep M, Irrgang KD, Freiberg A. Chromophore−Chromophore and Chromophore−Protein Interactions in Monomeric Light-Harvesting Complex II of Green Plants Studied by Spectral Hole Burning and Fluorescence Line Narrowing. J Phys Chem B 2009; 113:10870-80. [DOI: 10.1021/jp900836p] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jörg Pieper
- Max-Volmer-Laboratories for Biophysical Chemistry, Technical University Berlin, Berlin, Germany, Institute of Physics, University of Tartu, Tartu, Estonia, Department of Life Science & Technology, Laboratory of Biochemistry, University for Applied Sciences, Berlin, Germany, and Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Margus Rätsep
- Max-Volmer-Laboratories for Biophysical Chemistry, Technical University Berlin, Berlin, Germany, Institute of Physics, University of Tartu, Tartu, Estonia, Department of Life Science & Technology, Laboratory of Biochemistry, University for Applied Sciences, Berlin, Germany, and Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Klaus-Dieter Irrgang
- Max-Volmer-Laboratories for Biophysical Chemistry, Technical University Berlin, Berlin, Germany, Institute of Physics, University of Tartu, Tartu, Estonia, Department of Life Science & Technology, Laboratory of Biochemistry, University for Applied Sciences, Berlin, Germany, and Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Arvi Freiberg
- Max-Volmer-Laboratories for Biophysical Chemistry, Technical University Berlin, Berlin, Germany, Institute of Physics, University of Tartu, Tartu, Estonia, Department of Life Science & Technology, Laboratory of Biochemistry, University for Applied Sciences, Berlin, Germany, and Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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Reppert M, Zazubovich V, Dang NC, Seibert M, Jankowiak R. Low-Energy Chlorophyll States in the CP43 Antenna Protein Complex: Simulation of Various Optical Spectra. II. J Phys Chem B 2008; 112:9934-47. [DOI: 10.1021/jp8013749] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mike Reppert
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506,, Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada, and National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Valter Zazubovich
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506,, Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada, and National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Nhan C. Dang
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506,, Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada, and National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Michael Seibert
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506,, Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada, and National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506,, Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada, and National Renewable Energy Laboratory, Golden, Colorado 80401
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28
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Dang NC, Zazubovich V, Reppert M, Neupane B, Picorel R, Seibert M, Jankowiak R. The CP43 proximal antenna complex of higher plant photosystem II revisited: modeling and hole burning study. I. J Phys Chem B 2008; 112:9921-33. [PMID: 18642949 DOI: 10.1021/jp801373c] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The CP43 core antenna complex of photosystem II is known to possess two quasi-degenerate "red"-trap states (Jankowiak, R. et al. J. Phys. Chem. B 2000, 104, 11805). It has been suggested recently (Zazubovich, V.; Jankowiak, R. J. Lumin. 2007, 127, 245) that the site distribution functions of the red states (A and B) are uncorrelated and that narrow holes are burned in the subpopulations of chlorophylls (Chls) from states A and B that are the lowest-energy Chl in their complex and previously thought not to transfer energy. This model of uncorrelated excitation energy transfer (EET) between the quasidegenerate bands is expanded by taking into account both electron-phonon and vibrational coupling. The model is applied to fit simultaneously absorption, emission, zero-phonon action, and transient hole burned (HB) spectra obtained for the CP43 complex with minimized contribution from aggregation. It is demonstrated that the above listed spectra can be well-fitted using the uncorrelated EET model, providing strong evidence for the existence of efficient energy transfer between the two lowest energy states, A and B (either from A to B or from B to A), in CP43. Possible candidate Chls for the low-energy A and B states are discussed, providing a link between CP43 structure and spectroscopy. Finally, we propose that persistent holes originate from regular NPHB accompanied by the redistribution of oscillator strength due to excitonic interactions, rather than photoconversion involving Chl-protein hydrogen bonding, as suggested before ( Hughes J. L. et al. Biochemistry 2006, 45, 12345 ). In the accompanying paper (Reppert, M.; Zazubovich, V.; Dang, N. C.; Seibert, M.; Jankowiak, R. J. Phys. Chem. B 2008, 9934), it is demonstrated that the model discussed in this manuscript is consistent with excitonic calculations, which also provide very good fits to both transient and persistent HB spectra obtained under non-line-narrowing conditions.
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Affiliation(s)
- Nhan C Dang
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, USA
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Vassiliev S, Bruce D. Toward understanding molecular mechanisms of light harvesting and charge separation in photosystem II. PHOTOSYNTHESIS RESEARCH 2008; 97:75-89. [PMID: 18443918 DOI: 10.1007/s11120-008-9303-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 03/31/2008] [Indexed: 05/26/2023]
Abstract
Conversion of light energy in photosynthesis is extremely fast and efficient, and understanding the nature of this complex photophysical process is challenging. This review describes current progress in understanding molecular mechanisms of light harvesting and charge separation in photosystem II (PSII). Breakthroughs in X-ray crystallography have allowed the development and testing of more detailed kinetic models than have previously been possible. However, due to the complexity of the light conversion processes, satisfactory descriptions remain elusive. Recent advances point out the importance of variations in the photochemical properties of PSII in situ in different thylakoid membrane regions as well as the advantages of combining sophisticated time-resolved spectroscopic experiments with atomic level computational modeling which includes the effects of molecular dynamics.
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Affiliation(s)
- Serguei Vassiliev
- Department of Biology, Brock University, St. Catharines, ON, Canada L2S 3A1.
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Raszewski G, Renger T. Light harvesting in photosystem II core complexes is limited by the transfer to the trap: can the core complex turn into a photoprotective mode? J Am Chem Soc 2008; 130:4431-46. [PMID: 18327941 DOI: 10.1021/ja7099826] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A structure-based modeling and analysis of the primary photophysical reactions in photosystem II (PS-II) core complexes is presented. The modeling is based on a description of stationary and time-resolved optical spectra of the CP43, CP47, and D1-D2-cytb559 subunits and whole core complexes. It shows that the decay of excited states in PS-II core complexes with functional (open) reaction centers (RCs) is limited by the excitation energy transfer from the CP43 and CP47 core antennae to the RC occurring with a time constant of 40-50 ps at room temperature. The chlorophylls responsible for the low energy absorbance bands in the CP43 and CP47 subunits are assigned, and their signatures in hole burning, fluorescence line narrowing, and triplet-minus-singlet spectra are explained. The different locations of these trap states in the CP43 and CP47 antennae with respect to the reaction center lead to a dramatic change of the transfer dynamics at low temperatures. The calculations predict that, compared to room temperature, the fluorescence decay at 77 K should reveal a faster transfer from CP43 and a much slower and highly dispersive transfer from CP47 to the RC. A factor of 3 increase in the fastest decay time constant of fluorescence that was reported to occur when the RC is closed (the plastoquinone QA is reduced) is understood in the present model by assuming that the intrinsic rate constant for primary electron transfer decreases from 100 fs-1 for open RCs to 6 ps-1 for closed RCs, leading to a reduction of the primary electron acceptor PheoD1, in 300 fs and 18 ps, respectively. The model suggests that the reduced QA switches the photosystem into a photoprotective mode in which a large part of the excitation energy of the RC returns to the CP43 and CP47 core antennae, where the physiologically dangerous triplet energy of the chlorophylls can be quenched by the carotenoids. Experiments are suggested to test this hypothesis. The ultrafast primary electron transfer inferred for open RCs provides further support for the accessory chlorophyll ChlD1 to be the primary electron donor in photosystem II.
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Affiliation(s)
- Grzegorz Raszewski
- Institut für Chemie und Biochemie (Kristallographie), Freie Universität Berlin, Fabeckstrasse 36a, 6, D-14195 Berlin, Germany
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31
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Müh F, Renger T, Zouni A. Crystal structure of cyanobacterial photosystem II at 3.0 A resolution: a closer look at the antenna system and the small membrane-intrinsic subunits. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2008; 46:238-64. [PMID: 18313317 DOI: 10.1016/j.plaphy.2008.01.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Indexed: 05/04/2023]
Abstract
Photosystem II (PSII) is a homodimeric protein-cofactor complex embedded in the thylakoid membrane that catalyses light-driven charge separation accompanied by the water splitting reaction during oxygenic photosynthesis. In the first part of this review, we describe the current state of the crystal structure at 3.0 A resolution of cyanobacterial PSII from Thermosynechococcus elongatus [B. Loll et al., Towards complete cofactor arrangement in the 3.0 A resolution structure of photosystem II, Nature 438 (2005) 1040-1044] with emphasis on the core antenna subunits CP43 and CP47 and the small membrane-intrinsic subunits. The second part describes first the general theory of optical spectra and excitation energy transfer and how the parameters of the theory can be obtained from the structural data. Next, structure-function relationships are discussed that were identified from stationary and time-resolved experiments and simulations of optical spectra and energy transfer processes.
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Affiliation(s)
- Frank Müh
- Institut für Chemie und Biochemie/Kristallographie, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany
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Qu Y, Chen H, Qin X, Li L, Wang L, Kuang T. Thermal denaturation of CP43 studied by Fourier transform-infrared spectroscopy and terahertz time-domain spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:1614-8. [DOI: 10.1016/j.bbapap.2007.08.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2007] [Revised: 08/26/2007] [Accepted: 08/28/2007] [Indexed: 11/25/2022]
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Di Donato M, van Grondelle R, van Stokkum IHM, Groot ML. Excitation Energy Transfer in the Photosystem II Core Antenna Complex CP43 Studied by Femtosecond Visible/Visible and Visible/Mid-Infrared Pump Probe Spectroscopy. J Phys Chem B 2007; 111:7345-52. [PMID: 17550278 DOI: 10.1021/jp068315+] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Excitation energy transfer in the Photosystem II core antenna complex CP43 has been investigated by vis/vis and vis/mid-IR pump-probe spectroscopy with the aim of understanding the relation between the dynamics of energy transfer and the structural arrangement of individual chlorophyll molecules within the protein. Energy transfer was found to occur on time scales of 250 fs, 2-4 ps, and 10-12 ps. The vis/mid-IR difference spectra show that the excitation is initially distributed over chlorophylls located in environments with different polarity, since two 9-keto C=O stretching bleachings, at 1691 and 1677 cm-1, are observable at early delay times. Positive signals in the initial difference spectra around 1750 and 1720 cm-1 indicate the presence of a charge transfer state between strongly interacting chlorophylls. We conclude, both from the spectral behavior in the visible when the annihilation processes are increased and from the vis/mid-IR data, that there are two pigments (one absorbing around 670 nm and one at 683 nm) which are not connected to the other pigments on a time scale faster than 10-20 ps. Since, in the IR, on a 10 ps time scale the population of the 1691 cm-1 mode almost disappears, while the 1677 cm-1 mode is still significantly populated, we can conclude that at least some of the red absorbing pigments are located in a polar environment, possibly forming H-bonds with the surrounding protein.
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Affiliation(s)
- Mariangela Di Donato
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands
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Qu Y, Chen H, Qin X, Wang L, Li L, Kuang T. The guanidine hydrochloride-induced denaturation of CP43 and CP47 studied by terahertz time-domain spectroscopy. ACTA ACUST UNITED AC 2007; 50:350-5. [PMID: 17609892 DOI: 10.1007/s11427-007-0048-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Accepted: 12/04/2006] [Indexed: 10/23/2022]
Abstract
Terahertz time-domain spectroscopy (THz-TDS) is a new technique in studying the conformational state of a molecule in recent years. In this work, we reported the first use of THz-TDS to examine the denaturation of two photosynthesis membrane proteins: CP43 and CP47. THz-TDS was proven to be useful in discriminating the different conformational states of given proteins with similar structure and in monitoring the denaturation process of proteins. Upon treatment with guanidine hydrochloride (GuHCl), a 1.8 THz peak appeared for CP47 and free chlorophyll a (Chl a). This peak was deemed to originate from the interaction between Chl a and GuHCl molecules. The Chl a molecules in CP47 interacted with GuHCl more easily than those in CP43.
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Affiliation(s)
- YuanGang Qu
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China,
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Komura M, Shibata Y, Itoh S. A new fluorescence band F689 in photosystem II revealed by picosecond analysis at 4–77 K: Function of two terminal energy sinks F689 and F695 in PS II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:1657-68. [PMID: 17070496 DOI: 10.1016/j.bbabio.2006.09.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 09/22/2006] [Accepted: 09/26/2006] [Indexed: 11/29/2022]
Abstract
We performed picosecond time-resolved fluorescence spectroscopy in spinach photosystem II (PS II) particles at 4, 40, and 77 K and identified a new fluorescence band, F689. F689 was identified in addition to the well-known F685 and F695 bands in both analyses of decay-associated spectra and global Gaussian deconvolution of time-resolved spectra. Its fast decay suggests the energy transfer directly from F689 to the reaction center chlorophyll P680. The contribution of F689, which increases only at low temperature, explains the unusually broad and variable bandwidth of F695 at low temperature. Global analysis revealed the three types of excitation energy transfer/dissipation processes: (1) energy transfer from the peripheral antenna to the three core antenna bands F685, F689, and F695 with time constants of 29 and 171 ps at 77 and 4 K, respectively; (2) between the three core bands (0.18 and 0.82 ns); and (3) the decays of F689 (0.69 and 3.02 ns) and F695 (2.18 and 4.37 ns). The retardations of these energy transfer rates and the slow F689 decay rate produced the strong blue shift of the PS II fluorescence upon the cooling below 77 K.
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Affiliation(s)
- Masayuki Komura
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8602, Japan
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Riley KJ, Zazubovich V, Jankowiak R. Frequency-Domain Spectroscopic Study of the PS I−CP43‘ Supercomplex from the Cyanobacterium Synechocystis PCC 6803 Grown under Iron Stress Conditions. J Phys Chem B 2006; 110:22436-46. [PMID: 17091985 DOI: 10.1021/jp063691f] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Absorption, fluorescence excitation, emission, and hole-burning (HB) spectra were measured at liquid helium temperatures for the PS I-CP43' supercomplexes of Synechocystis PCC 6803 grown under iron stress conditions and for respective trimeric PS I cores. Results are compared with those of room temperature, time-domain experiments (Biochemistry 2003, 42, 3893) as well as with the low-temperature steady-state experiments on PS I-CP43' supercomplexes of Synechococcus PCC 7942 (Biochim. Biophys. Acta 2002, 1556, 265). In contrast to the CP43' of Synechococcus PCC 7942, CP43' of Synechocystis PCC 6803 possesses two low-energy states analogous to the quasidegenerate states A and B of CP43 of photosystem II (J. Phys. Chem. B 2000, 104, 11805). Energy transfer between the CP43' and the PS I core occurs, to a significant degree, through the state A, characterized with a broader site distribution function (SDF). It is demonstrated that the low temperature (T = 5 K) excitation energy transfer (EET) time between the state A of CP43' (IsiA) and the PS I core in PS I-CP43' supercomplexes from Synechocystis PCC 6803 is about 60 ps, which is significantly slower than the EET observed at room temperature. Our results are consistent with fast (< or =10 ps) energy transfer from state B to state A in CP43'. Energy absorbed by the CP43' manifold has, on average, a greater chance of being transferred to the reaction center (RC) and utilized for charge separation than energy absorbed by the PS I core antenna. This indicates that energy is likely transferred from the CP43' to the RC along a well-defined path and that the "red antenna states" of the PS I core are localized far away from that path, most likely on the B7-A32 and B37-B38 dimers in the vicinity of the PS I trimerization domain (near PsaL subunit). We argue that the A38-A39 dimer does not contribute to the red antenna region.
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Affiliation(s)
- Kerry J Riley
- Ames Laboratory-USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, USA
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Hughes JL, Picorel R, Seibert M, Krausz E. Photophysical Behavior and Assignment of the Low-Energy Chlorophyll States in the CP43 Proximal Antenna Protein of Higher Plant Photosystem II. Biochemistry 2006; 45:12345-57. [PMID: 17014087 DOI: 10.1021/bi0614683] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have employed absorption, circular dichroism (CD), and persistent spectral hole-burning measurements at 1.7 K to study the photoconversion properties and exciton coupling of low-energy chlorophylls (Chls) in the CP43 proximal antenna light-harvesting subunit of photosystem II (PSII) isolated from spinach. These approximately 683 nm states act as traps for excitation energy in isolated CP43. They "bleach" at 683 nm upon illumination and photoconvert to a form absorbing in the range approximately 660-680 nm. We present new data that show the changes in the CD spectrum due to the photoconversion process. These changes occur in parallel with those in absorption, providing evidence that the feature undergoing the apparent bleach is a component of a weakly exciton-coupled system. From our photoconversion difference spectra, we assign four states in the Chl long-wavelength region of CP43, two of which are the known trap states and are both highly localized on single Chls. The other two states are associated with weak exciton coupling (maximally approximately 50 cm(-)(1)) to one of these traps. We propose a mechanism for photoconversion that involves Chl-protein hydrogen bonding. New hole-burning data are presented that indicate this mechanism is distinct to that for narrow-band spectral hole burning in CP43. We discuss the photophysical behavior of the Chl trap states in isolated CP43 compared to their behavior in intact PSII preparations. The latter represent a more intact, physiological complex, and we find no clear evidence that they exhibit the photoconversion process reported here.
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Affiliation(s)
- Joseph L Hughes
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia.
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38
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Hughes JL, Smith P, Pace R, Krausz E. Charge separation in photosystem II core complexes induced by 690-730 nm excitation at 1.7 K. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:841-51. [PMID: 16859635 DOI: 10.1016/j.bbabio.2006.05.035] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 05/01/2006] [Accepted: 05/22/2006] [Indexed: 11/24/2022]
Abstract
The illumination of oxygen-evolving PSII core complexes at very low temperatures in spectral regions not expected to excite P680 leads to charge separation in a majority of centers. The fraction of centers photoconverted as a function of the number of absorbed photons per PSII core is determined by quantification of electrochromic shifts on Pheo(D1). These shifts arise from the formation of metastable plastoquinone anion (Q(A)(-)) configurations. Spectra of concentrated samples identify absorption in the 700-730 nm range. This is well beyond absorption attributable to CP47. Spectra in the 690-730 nm region can be described by the 'trap' CP47 absorption at 689 nm, with dipole strength of approximately 1 chlorophyll a (chl a), partially overlapping a broader feature near 705 nm with a dipole strength of approximately 0.15 chl a. This absorption strength in the 700-730 nm region falls by 40% in the photoconverted configuration. Quantum efficiencies of photoconversion following illumination in the 690-700 nm region are similar to those obtained with green illumination but fall significantly in the 700-730 nm range. Two possible assignments of the long-wavelength absorption are considered. Firstly, as a low intensity component of strongly exciton-coupled reaction center chlorin excitations and secondly as a nominally 'dark' charge-transfer excitation of the 'special pair' P(D1)-P(D2). The opportunities offered by these observations towards the understanding of the nature of P680 and PSII fluorescence are discussed.
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Affiliation(s)
- Joseph L Hughes
- Research School of Chemistry, Australian National University, Canberra
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39
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Krausz E, Hughes JL, Smith PJ, Pace RJ, Arsköld SP. Assignment of the low-temperature fluorescence in oxygen-evolving photosystem II. PHOTOSYNTHESIS RESEARCH 2005; 84:193-9. [PMID: 16049774 DOI: 10.1007/s11120-004-7078-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Accepted: 12/02/2004] [Indexed: 05/03/2023]
Abstract
Low-temperature absorption and fluorescence spectra of fully active cores and membrane-bound PS II preparations are compared. Detailed temperature dependence of fluorescence spectra between 5 and 70 K are presented as well as 1.7-K fluorescence line-narrowed (FLN) spectra of cores, confirming that PS II emission is composite. Spectra are compared to those reported for LHCII, CP43, CP47 and D1/D2/cytit b559 subunits of PS II. A combination of subunit spectra cannot account for emission of active PS II. The complex temperature dependence of PS II fluorescence is interpretable by noting that excitation transfer from CP43 and CP47 to the reaction centre is slow, and strongly dependent on the precise energy at which a 'slow-transfer' pigment in CP43 or CP47 is located within its inhomogeneous distribution. PS II fluorescence arises from CP43 and CP47 'slow-transfer' states, convolved by this dependence. At higher temperatures, thermally activated excitation transfer to the PS II charge-separating system bypasses such bottlenecks. As the charge-separating state of active PS II absorbs at >700 nm, PS II emission in the 680-700 nm region is unlikely to arise from reaction centre pigments. PS II emission at physiological temperatures is discussed in terms of these results.
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Affiliation(s)
- Elmars Krausz
- Research School of Chemistry, Australian National University, Building 35 Science Road, Canberra, ACT 0200, Australia.
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40
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Arsköld SP, Smith PJ, Shen JR, Pace RJ, Krausz E. Key cofactors of photosystem II cores from four organisms identified by 1.7-K absorption, CD and MCD. PHOTOSYNTHESIS RESEARCH 2005; 84:309-16. [PMID: 16049791 DOI: 10.1007/s11120-005-2135-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Accepted: 02/10/2005] [Indexed: 05/03/2023]
Abstract
Active Photosystem II (PS II) cores were prepared from spinach, pea, Synechocystis PCC 6803, and Thermosynechococcus vulcanus, the latter of which has been structurally determined [Kamiya and Shen (2003) Proc Natl Acad Sci USA 100: 98-103]. Electrochromic shifts resulting from QA reduction by 1.7-K illumination were recorded, and the Qx and Qy absorption bands of the redox-active pheophytin a thus identified in the different organisms. The Qx transition is approximately 3 nm (100 cm-1) to higher energy in cyanobacteria than in the plants. The predominant Qy shift appears in the range 683-686 nm depending on species, and does not appear to have a systematic shift. Low-temperature absorption, circular dichroism (CD) and magnetic circular dichroism (MCD) spectra of the chlorophyll Qy region are very similar in spinach and pea, but vary in cyanobacteria. We assigned CP43 and CP47 trap-chlorophyll absorption features in all species, as well as a P680 transition. Each absorption identified has an area of one chlorophyll a. The MCD deficit, introduced previously for spinach as an indicator of P680 activity, occurs in the same spectral region and has the same area in all species, pointing to a robustness of this as a signature for P680. MCD and CD characteristics point towards a significant variance in P680 structure between cyanobacteria, thermophilic cyanobacteria, and higher plants.
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Affiliation(s)
- Sindra Peterson Arsköld
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia.
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41
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Melkozernov AN, Blankenship RE. Structural and functional organization of the peripheral light-harvesting system in photosystem I. PHOTOSYNTHESIS RESEARCH 2005; 85:33-50. [PMID: 15977058 DOI: 10.1007/s11120-004-6474-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2004] [Accepted: 11/19/2004] [Indexed: 05/03/2023]
Abstract
This review centers on the structural and functional organization of the light-harvesting system in the peripheral antenna of Photosystem I (LHC I) and its energy coupling to the Photosystem I (PS I) core antenna network in view of recently available structural models of the eukaryotic Photosystem I-LHC I complex, eukaryotic LHC II complexes and the cyanobacterial Photosystem I core. A structural model based on the 3D homology of Lhca4 with LHC II is used for analysis of the principles of pigment arrangement in the LHC I peripheral antenna, for prediction of the protein ligands for the pigments that are unique for LHC I and for estimates of the excitonic coupling in strongly interacting pigment dimers. The presence of chlorophyll clusters with strong pigment-pigment interactions is a structural feature of PS I, resulting in the characteristic red-shifted fluorescence. Analysis of the interactions between the PS I core antenna and the peripheral antenna leads to the suggestion that the specific function of the red pigments is likely to be determined by their localization with respect to the reaction center. In the PS I core antenna, the Chl clusters with a different magnitude of low energy shift contribute to better spectral overlap of Chls in the reaction center and the Chls of the antenna network, concentrate the excitation around the reaction center and participate in downhill enhancement of energy transfer from LHC II to the PS I core. Chlorophyll clusters forming terminal emitters in LHC I are likely to be involved in photoprotection against excess energy.
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Affiliation(s)
- Alexander N Melkozernov
- Department of Chemistry and Biochemistry, Center for the Study of Early Events in Photosynthesis, Tempe, AZ, 85287-1604, USA.
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Hughes JL, Prince BJ, Krausz E, Smith PJ, Pace RJ, Riesen H. Highly Efficient Spectral Hole-Burning in Oxygen-Evolving Photosystem II Preparations. J Phys Chem B 2004. [DOI: 10.1021/jp0492523] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joseph L. Hughes
- Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia, Faculties Chemistry, The Australian National University, Canberra ACT 0200, Australia, and School of Physical, Environmental and Mathematical Sciences, University College, The University of New South Wales, ADFA, Canberra ACT 2600, Australia
| | - Barry J. Prince
- Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia, Faculties Chemistry, The Australian National University, Canberra ACT 0200, Australia, and School of Physical, Environmental and Mathematical Sciences, University College, The University of New South Wales, ADFA, Canberra ACT 2600, Australia
| | - Elmars Krausz
- Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia, Faculties Chemistry, The Australian National University, Canberra ACT 0200, Australia, and School of Physical, Environmental and Mathematical Sciences, University College, The University of New South Wales, ADFA, Canberra ACT 2600, Australia
| | - Paul J. Smith
- Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia, Faculties Chemistry, The Australian National University, Canberra ACT 0200, Australia, and School of Physical, Environmental and Mathematical Sciences, University College, The University of New South Wales, ADFA, Canberra ACT 2600, Australia
| | - Ron J. Pace
- Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia, Faculties Chemistry, The Australian National University, Canberra ACT 0200, Australia, and School of Physical, Environmental and Mathematical Sciences, University College, The University of New South Wales, ADFA, Canberra ACT 2600, Australia
| | - Hans Riesen
- Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia, Faculties Chemistry, The Australian National University, Canberra ACT 0200, Australia, and School of Physical, Environmental and Mathematical Sciences, University College, The University of New South Wales, ADFA, Canberra ACT 2600, Australia
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43
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Hsin TM, Zazubovich V, Hayes JM, Small GJ. Red Antenna States of PS I of Cyanobacteria: Stark Effect and Interstate Energy Transfer. J Phys Chem B 2004. [DOI: 10.1021/jp049572m] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- T.-M. Hsin
- Department of Chemistry, Iowa State University and Ames Laboratory-USDOE, Ames, Iowa 50011
| | - V. Zazubovich
- Department of Chemistry, Iowa State University and Ames Laboratory-USDOE, Ames, Iowa 50011
| | - J. M. Hayes
- Department of Chemistry, Iowa State University and Ames Laboratory-USDOE, Ames, Iowa 50011
| | - G. J. Small
- Department of Chemistry, Iowa State University and Ames Laboratory-USDOE, Ames, Iowa 50011
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Arsköld SP, Masters VM, Prince BJ, Smith PJ, Pace RJ, Krausz E. Optical spectra of synechocystis and spinach photosystem II preparations at 1.7 K: identification of the D1-pheophytin energies and stark shifts. J Am Chem Soc 2004; 125:13063-74. [PMID: 14570479 DOI: 10.1021/ja034548s] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report and compare highly resolved, simultaneously recorded absorption and CD spectra of active Photosystem II (PSII) samples in the range 440-750 nm. From an appropriately scaled comparison of spinach membrane fragment (BBY) and PSII core spectra, we show that key features of the core spectrum are quantitatively represented in the BBY data. PSII from the cyanobacterium Synechocystis 6803 display spectral features in the Qy region of comparable width (50-70 cm(-1) fwhm) to those seen in plant PSII but the energies of the resolved features are distinctly different. A comparison of spectra taken of PSII poised in the S1QA and S2QA(-) redox states reveals electrochromic shifts largely attributable to the influence of QA(-) on Pheo(D1). This allows accurate determinations of the Pheo(D1) Qy absorption positions to be at 685.0 nm for spinach cores, 685.8 nm for BBY particles, and 683.0 nm for Synechocystis. These are discussed in terms of earlier reports of the Pheo(D1) energies in PSII. The Qx transition of Pheo(D1) undergoes a blue shift upon Q(A) reduction, and we place a lower limit of 80 cm(-1) on this shift in plant material. By comparing the magnitude of the Stark shifts of the Qx and Qy bands of Pheo(D1), the directions of the transition-induced dipole moment changes, Deltamu(x) and Deltamu(y), for this functionally important pigment could be determined, assuming normal magnitudes of the Deltamu's. Consequently, Deltamu(x) and Deltamu(y) are determined to be approximately orthogonal to the directions expected for these transitions. Low-fluence illumination experiments at 1.7 K resulted in very efficient formation of QA(-). This was accompanied by cyt b(559) oxidation in BBYs and carotenoid oxidation in cores. No chlorophyll oxidation was observed. Our data allow us to estimate the quantum efficiency of PSII at this temperature to be of the order 0.1-1. No Stark shift associated with the S1-to-S2 transition of the Mn cluster is evident in our samples. The similarity of Stark data in plants and Synechocystis points to minimal interactions of Pheo(D1) with nearby chloropyll pigments in active PSII preparations. This appears to be at variance with interpretations of experiments performed with inactive solubilized reaction-center preparations.
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Affiliation(s)
- Sindra Peterson Arsköld
- Research School of Chemistry and Department of Chemistry, Faculties of Science, Australian National University, Canberra ACT 0200, Australia.
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45
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Hughes JL, Prince BJ, Peterson Årsköld S, Smith PJ, Pace RJ, Riesen H, Krausz E. The Native Reaction Centre of Photosystem II: A New Paradigm for P680. Aust J Chem 2004. [DOI: 10.1071/ch04140] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Low-temperature spectra of fully active (oxygen-evolving) Photosystem II (PSII) cores prepared from spinach exhibit well developed structure. Spectra of isolated sub-fragments of PSII cores establish that the native reaction centre is better structured and red-shifted compared to the isolated reaction centre. Laser illumination of PSII cores leads to efficient and deep spectral hole-burning. Measurements of homogeneous hole-widths establish excited-state lifetimes in the 40–300 ps range. The high hole-burning efficiency is attributed to charge separation of P680 in native PSII that follows reaction-centre excitation via ‘slow transfer’ states in the inner light-harvesting assemblies CP43 and CP47. The ‘slow transfer’ state in CP47 and that in CP43 can be distinguished in the hole-burning action spectrum and high-resolution hole-burning spectra. An important observation is that 685–700 nm illumination gives rise to efficient P680 charge separation, as established by QA− formation. This leads to a new paradigm for P680. The charge-separating state has surprisingly weak absorption and extends to 700 nm.
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46
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de Weerd FL, Dekker JP, van Grondelle R. Dynamics of β-Carotene-to-Chlorophyll Singlet Energy Transfer in the Core of Photosystem II. J Phys Chem B 2003. [DOI: 10.1021/jp027737q] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Frank L. de Weerd
- Department of Biophysics and Physics of Complex Systems, Division of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Jan P. Dekker
- Department of Biophysics and Physics of Complex Systems, Division of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Department of Biophysics and Physics of Complex Systems, Division of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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47
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Spezia R, Aschi M, Nola AD, Valentin MD, Carbonera D, Amadei A. The effect of protein conformational flexibility on the electronic properties of a chromophore. Biophys J 2003; 84:2805-13. [PMID: 12719215 PMCID: PMC1302846 DOI: 10.1016/s0006-3495(03)70010-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
In this paper we address the question of how a protein environment can modulate the absorption spectrum of a chromophore during a molecular dynamics simulation. The effect of the protein is modeled as an external field acting on the unperturbed eigenstates of the chromophore. Using a first-principles method recently developed in our group, we calculated the perturbed electronic energies for each frame and the corresponding wavelength absorption during the simulation. We apply this method to a nanosencond timescale molecular dynamics simulation of the light-harvesting peridinin-chlorophyll-protein complex from Amphidinium carterae, where chlorophyll was selected among the chromophores of the complex for the calculation. The combination of this quantum-classical calculation with the analysis of the large amplitude motions of the protein makes it possible to point out the relationship between the conformational flexibility of the environment and the excitation wavelength of the chromophore. Results support the idea of the existence of a correlation between protein conformational flexibility and chlorophyll electronic transitions induced by light.
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Affiliation(s)
- Riccardo Spezia
- Dipartimento di Chimica, Università di Roma La Sapienza, Italy
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48
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49
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50
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De Weerd FL, Palacios MA, Andrizhiyevskaya EG, Dekker JP, Van Grondelle R. Identifying the lowest electronic states of the chlorophylls in the CP47 core antenna protein of photosystem II. Biochemistry 2002; 41:15224-33. [PMID: 12484760 DOI: 10.1021/bi0261948] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
CP47 is a pigment-protein complex in the core of photosystem II that tranfers excitation energy to the reaction center. Here we report on a spectroscopic investigation of the isolated CP47 complex. By deconvoluting the 77 K absorption and linear dichroism, red-most states at 683 and 690 nm have been identified with oscillator strengths corresponding to approximately 3 and approximately 1 chlorophyll, respectively. Both states contribute to the 4 K emission, and the Stark spectrum shows that they have a large value for the difference polarizability between their ground and excited states. From site-selective polarized triplet-minus-singlet spectra, an excitonic origin for the 683 nm state was found. The red shift of the 690 nm state is most probably due to strong hydrogen bonding to a protein ligand, as follows from the position of the stretch frequency of the chlorophyll 13(1) keto group (1633 cm(-)(1)) in the fluorescence line narrowing spectrum at 4 K upon red-most excitation. We discuss how the 683 and 690 nm states may be linked to specific chlorophylls in the crystal structure [Zouni, A., Witt, H.-T., Kern, J., Fromme, P., Krauss, N., Saenger, W., and Orth, P. (2001) Nature 409, 739-743].
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Affiliation(s)
- Frank L De Weerd
- Faculty of Sciences, Division of Physics and Astronomy, Department of Biophysics and Physics of Complex Systems, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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