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Gorka M, Charles P, Kalendra V, Baldansuren A, Lakshmi KV, Golbeck JH. A dimeric chlorophyll electron acceptor differentiates type I from type II photosynthetic reaction centers. iScience 2021; 24:102719. [PMID: 34278250 PMCID: PMC8267441 DOI: 10.1016/j.isci.2021.102719] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 05/17/2021] [Accepted: 06/09/2021] [Indexed: 01/09/2023] Open
Abstract
This research addresses one of the most compelling issues in the field of photosynthesis, namely, the role of the accessory chlorophyll molecules in primary charge separation. Using a combination of empirical and computational methods, we demonstrate that the primary acceptor of photosystem (PS) I is a dimer of accessory and secondary chlorophyll molecules, Chl2A and Chl3A, with an asymmetric electron charge density distribution. The incorporation of highly coupled donors and acceptors in PS I allows for extensive delocalization that prolongs the lifetime of the charge-separated state, providing for high quantum efficiency. The discovery of this motif has widespread implications ranging from the evolution of naturally occurring reaction centers to the development of a new generation of highly efficient artificial photosynthetic systems. Video abstract
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Affiliation(s)
- Michael Gorka
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Philip Charles
- Department of Chemistry and Chemical Biology and The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Vidmantas Kalendra
- Department of Chemistry and Chemical Biology and The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Amgalanbaatar Baldansuren
- Department of Chemistry and Chemical Biology and The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - K V Lakshmi
- Department of Chemistry and Chemical Biology and The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.,Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
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Charles P, Kalendra V, He Z, Khatami MH, Golbeck JH, van der Est A, Lakshmi KV, Bryant DA. Two-dimensional 67Zn HYSCORE spectroscopy reveals that a Zn-bacteriochlorophyll aP′ dimer is the primary donor (P840) in the type-1 reaction centers of Chloracidobacterium thermophilum. Phys Chem Chem Phys 2020; 22:6457-6467. [DOI: 10.1039/c9cp06556c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Using pulsed EPR spectroscopy and isotopic labeling we demonstrate that reaction centers of Chloracidobacterium thermophilum have an unusual primary donor that is a dimer of Zn-bacteriochlorophyll aP′ molecules.
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Affiliation(s)
- Philip Charles
- Departments of Chemistry and Physics and The Baruch ’60 Center for Biochemical Solar Energy Research
- Rensselaer Polytechnic Institute
- Troy
- USA
| | - Vidmantas Kalendra
- Departments of Chemistry and Physics and The Baruch ’60 Center for Biochemical Solar Energy Research
- Rensselaer Polytechnic Institute
- Troy
- USA
| | - Zhihui He
- Department of Biochemistry and Molecular Biology
- The Pennsylvania State University
- State College
- USA
| | | | - John H. Golbeck
- Department of Biochemistry and Molecular Biology
- The Pennsylvania State University
- State College
- USA
- Department of Chemistry
| | | | - K. V. Lakshmi
- Departments of Chemistry and Physics and The Baruch ’60 Center for Biochemical Solar Energy Research
- Rensselaer Polytechnic Institute
- Troy
- USA
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology
- The Pennsylvania State University
- State College
- USA
- Department of Chemistry and Biochemistry
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Zill JC, Kansy M, Goss R, Alia A, Wilhelm C, Matysik J. 15N photo-CIDNP MAS NMR on both photosystems and magnetic field-dependent 13C photo-CIDNP MAS NMR in photosystem II of the diatom Phaeodactylum tricornutum. PHOTOSYNTHESIS RESEARCH 2019; 140:151-171. [PMID: 30194671 DOI: 10.1007/s11120-018-0578-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 08/24/2018] [Indexed: 05/14/2023]
Abstract
Diatoms contribute about 20-25% to the global marine productivity and are successful autotrophic players in all aquatic ecosystems, which raises the question whether this performance is caused by differences in their photosynthetic apparatus. Photo-CIDNP MAS NMR presents a unique tool to obtain insights into the reaction centres of photosystems (PS), by selective enhancement of NMR signals from both, the electron donor and the primary electron acceptor molecules. Here, we present the first observation of the solid-state photo-CIDNP effect in the pennate diatoms. In comparison to plant PSs, similar spectral patterns have been observed for PS I at 9.4 T and PS II at 4.7 T in the PSs of Phaeodactylum tricornutum. Studies at different magnetic fields reveal a surprising sign change of the 13C photo-CIDNP MAS NMR signals indicating an alternative arrangement of cofactors which allows to quench the Chl a donor triplet state in contrast to the situation in plant PS II. This unusual quenching mechanism is related to a carotenoid molecule in close vicinity to the Chl a donor. In addition to the photo-CIDNP MAS NMR signals arising from the donor and the primary electron acceptor cofactors, a complete set of signals of the imidazole ring ligating to the magnesium of Chl a can be observed.
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Affiliation(s)
- Jeremias C Zill
- Institute of Analytical Chemistry, University of Leipzig, Johannisallee 29, 04103, Leipzig, Germany
| | - Marcel Kansy
- Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103, Leipzig, Germany
| | - Reimund Goss
- Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103, Leipzig, Germany
| | - A Alia
- Leiden Institute of Chemistry, University of Leiden, Einsteinweg 55, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04107, Leipzig, Germany
| | - Christian Wilhelm
- Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103, Leipzig, Germany
| | - Jörg Matysik
- Institute of Analytical Chemistry, University of Leipzig, Johannisallee 29, 04103, Leipzig, Germany.
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Zill JC, Kansy M, Goss R, Köhler L, Alia A, Wilhelm C, Matysik J. Photo-CIDNP in the Reaction Center of the Diatom Cyclotella meneghiniana Observed by 13C MAS NMR. Z PHYS CHEM 2016. [DOI: 10.1515/zpch-2016-0806] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Photo-CIDNP MAS NMR presents a unique tool to obtain insight into the photosynthetic reaction centers (RCs) of bacteria and plants. Using the dramatic enhancement of sensitivity and selectivity of the solid-state photo-CIDNP effect, structural as well as functional information can be obtained from the cofactor molecules forming a light-induced spin-correlated radical pair (SCRP) in a given reaction center. Here we demonstrate that the effect can be observed in a further species, which belongs neither to the plant nor the bacteria kingdom. Cyclotella (C.) meneghiniana is a member of the diatom phylum and, therefore, belongs to the kingdom of chromista. Chromista are some of the most productive organisms in nature, even in comparison to trees and terrestrial grasses. The observation of the effect in chromista indicates that the effect occurs in all photosynthetic organisms and completes the list with the last phototrophic kingdoms. Our data also demonstrate that the photo- and spin-chemical machineries of photosystem I of plants and chromista are very similar with respect to structure as well as function.
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Affiliation(s)
- Jeremias C. Zill
- University of Leipzig, Institute of Analytical Chemistry, Johannisallee 29, D-04103 Leipzig, Germany
| | - Marcel Kansy
- University of Leipzig, Institute of Biology, Abteilung Pflanzenphysiologie, Johannisallee 21-23, D-04103 Leipzig, Germany
| | - Reimund Goss
- University of Leipzig, Institute of Biology, Abteilung Pflanzenphysiologie, Johannisallee 21-23, D-04103 Leipzig, Germany
| | - Lisa Köhler
- University of Leipzig, Institute of Analytical Chemistry, Johannisallee 29, D-04103 Leipzig, Germany
| | - A. Alia
- University of Leiden, Leiden Institute of Chemistry, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands
- University of Leipzig, Institute of Medical Physics and Biophysics, Härtelstr. 16-18, D-04107 Leipzig, Germany
| | - Christian Wilhelm
- University of Leipzig, Institute of Biology, Abteilung Pflanzenphysiologie, Johannisallee 21-23, D-04103 Leipzig, Germany
| | - Jörg Matysik
- University of Leipzig, Institute of Analytical Chemistry, Johannisallee 29, D-04103 Leipzig, Germany
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High-Time Resolution Electron Paramagnetic Resonance Study of Quantum Beat Oscillations Observed in Photosynthetic Reaction Center Proteins. BIOPHYSICAL TECHNIQUES IN PHOTOSYNTHESIS 2008. [DOI: 10.1007/978-1-4020-8250-4_15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Golbeck JH. The binding of cofactors to photosystem I analyzed by spectroscopic and mutagenic methods. ANNUAL REVIEW OF BIOPHYSICS AND BIOMOLECULAR STRUCTURE 2003; 32:237-56. [PMID: 12524325 DOI: 10.1146/annurev.biophys.32.110601.142356] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This review focuses on cofactor-ligand and protein-protein interactions within the photosystem I reaction center. The topics include a description of the electron transfer cofactors, the mode of binding of the cofactors to protein-bound ligands, and a description of intraprotein contacts that ultimately allow photosystem I to be assembled (in cyanobacteria) from 96 chlorophylls, 22 carotenoids, 2 phylloquinones, 3 [4Fe-4S] clusters, and 12 polypeptides. During the 15 years that have elapsed from the first report of crystals to the atomic-resolution X-ray crystal structure, cofactor-ligand interactions and protein-protein interactions were systematically being explored by spectroscopic and genetic methods. This article charts the interplay between these disciplines and assesses how good the early insights were in light of the current structure of photosystem I.
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Affiliation(s)
- John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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Plato M, Krauß N, Fromme P, Lubitz W. Molecular orbital study of the primary electron donor P700 of photosystem I based on a recent X-ray single crystal structure analysis. Chem Phys 2003. [DOI: 10.1016/s0301-0104(03)00378-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Webber AN, Lubitz W. P700: the primary electron donor of photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1507:61-79. [PMID: 11687208 DOI: 10.1016/s0005-2728(01)00198-0] [Citation(s) in RCA: 211] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The primary electron donor of photosystem I, P700, is a chlorophyll species that in its excited state has a potential of approximately -1.2 V. The precise chemical composition and electronic structure of P700 is still unknown. Recent evidence indicates that P700 is a dimer of one chlorophyll (Chl) a and one Chl a'. The Chl a' and Chl a are axially coordinated by His residues provided by protein subunits PsaA and PsaB, respectively. The Chl a', but not the Chl a, is also H-bonded to the protein. The H-bonding is likely responsible for selective insertion of Chl a' into the reaction center. EPR studies of P700(+*) in frozen solution and single crystals indicate a large asymmetry in the electron spin and charge distribution towards one Chl of the dimer. Molecular orbital calculations indicate that H-bonding will specifically stabilize the Chl a'-side of the dimer, suggesting that the unpaired electron would predominantly reside on the Chl a. This is supported by results of specific mutagenesis of the PsaA and PsaB axial His residues, which show that only mutations of the PsaB subunit significantly alter the hyperfine coupling constants associated with a single Chl molecule. The PsaB mutants also alter the microwave induced triplet-minus-singlet spectrum indicating that the triplet state is localized on the same Chl. Excitonic coupling between the two Chl a of P700 is weak due to the distance and overlap of the porphyrin planes. Evidence of excitonic coupling is found in PsaB mutants which show a new bleaching band at 665 nm that likely represents an increased intensity of the upper exciton band of P700. Additional properties of P700 that may give rise to its unusually low potential are discussed.
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Affiliation(s)
- A N Webber
- Department of Plant Biology and Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe 85287-1601, USA.
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Deligiannakis Y, Rutherford AW. Electron spin echo envelope modulation spectroscopy in photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1507:226-46. [PMID: 11687217 DOI: 10.1016/s0005-2728(01)00201-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The applications of electron spin echo envelope modulation (ESEEM) spectroscopy to study paramagnetic centers in photosystem I (PSI) are reviewed with special attention to the novel spectroscopic techniques applied and the structural information obtained. We briefly summarize the physical principles and experimental techniques of ESEEM, the spectral shapes and the methods for their analysis. In PSI, ESEEM spectroscopy has been used to the study of the cation radical form of the primary electron donor chlorophyll species, P(700)(+), and the phyllosemiquinone anion radical, A(1)(-), that acts as a low-potential electron carrier. For P(700)(+), ESEEM has contributed to a debate concerning whether the cation is localized on a one or two chlorophyll molecules. This debate is treated in detail and relevant data from other methods, particularly electron nuclear double resonance (ENDOR), are also discussed. It is concluded that the ESEEM and ENDOR data can be explained in terms of five distinct nitrogen couplings, four from the tetrapyrrole ring and a fifth from an axial ligand. Thus the ENDOR and ESEEM data can be fully accounted for based on the spin density being localized on a single chlorophyll molecule. This does not eliminate the possibility that some of the unpaired spin is shared with the other chlorophyll of P(700)(+); so far, however, no unambiguous evidence has been obtained from these electron paramagnetic resonance methods. The ESEEM of the phyllosemiquinone radical A(1)(-) provided the first evidence for a tryptophan molecule pi-stacked over the semiquinone and for a weaker interaction from an additional nitrogen nucleus. Recent site-directed mutagenesis studies verified the presence of the tryptophan close to A(1), while the recent crystal structure showed that the tryptophan was indeed pi-stacked and that a weak potential H-bond from an amide backbone to one of the (semi)quinone carbonyls is probably the origin of the to the second nitrogen coupling seen in the ESEEM. ESEEM has already played an important role in the structural characterization on PSI and since it specifically probes the radical forms of the chromophores and their protein environment, the information obtained is complimentary to the crystallography. ESEEM then will continue to provide structural information that is often unavailable using other methods.
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Affiliation(s)
- Y Deligiannakis
- Laboratory of Physical Chemistry, Department of Environment and Natural Resources, University of Ioannina, Greece.
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11
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Rigby SE, Evans MC, Heathcote P. Electron nuclear double resonance (ENDOR) spectroscopy of radicals in photosystem I and related Type 1 photosynthetic reaction centres. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1507:247-59. [PMID: 11687218 DOI: 10.1016/s0005-2728(01)00211-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- S E Rigby
- School of Biological Sciences, University of London, UK.
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Abstract
In plants and cyanobacteria, the primary step in oxygenic photosynthesis, the light induced charge separation, is driven by two large membrane intrinsic protein complexes, the photosystems I and II. Photosystem I catalyses the light driven electron transfer from plastocyanin/cytochrome c(6) on the lumenal side of the membrane to ferredoxin/flavodoxin at the stromal side by a chain of electron carriers. Photosystem I of Synechococcus elongatus consists of 12 protein subunits, 96 chlorophyll a molecules, 22 carotenoids, three [4Fe4S] clusters and two phylloquinones. Furthermore, it has been discovered that four lipids are intrinsic components of photosystem I. Photosystem I exists as a trimer in the native membrane with a molecular mass of 1068 kDa for the whole complex. The X-ray structure of photosystem I at a resolution of 2.5 A shows the location of the individual subunits and cofactors and provides new information on the protein-cofactor interactions. [P. Jordan, P. Fromme, H.T. Witt, O. Klukas, W. Saenger, N. Krauss, Nature 411 (2001) 909-917]. In this review, biochemical data and results of biophysical investigations are discussed with respect to the X-ray crystallographic structure in order to give an overview of the structure and function of this large membrane protein.
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Affiliation(s)
- P Fromme
- Max Volmer Laboratorium für Biophysikalische Chemie Institut für Chemie, Technische Universität Berlin, Germany.
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Chitnis PR. PHOTOSYSTEM I: Function and Physiology. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:593-626. [PMID: 11337410 DOI: 10.1146/annurev.arplant.52.1.593] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Photosystem I is the light-driven plastocyanin-ferredoxin oxidoreductase in the thylakoid membranes of cyanobacteria and chloroplasts. In recent years, sophisticated spectroscopy, molecular genetics, and biochemistry have been used to understand the light conversion and electron transport functions of photosystem I. The light-harvesting complexes and internal antenna of photosystem I absorb photons and transfer the excitation energy to P700, the primary electron donor. The subsequent charge separation and electron transport leads to the reduction of ferredoxin. The photosystem I proteins are responsible for the precise arrangement of cofactors and determine redox properties of the electron transfer centers. With the availability of genomic information and the structure of photosystem I, one can now probe the functions of photosystem I proteins and cofactors. The strong reductant produced by photosystem I has a central role in chloroplast metabolism, and thus photosystem I has a critical role in the metabolic networks and physiological responses in plants.
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Affiliation(s)
- Parag R Chitnis
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011; e-mail:
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Hippler M, Redding K, Rochaix JD. Chlamydomonas genetics, a tool for the study of bioenergetic pathways. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1367:1-62. [PMID: 9784589 DOI: 10.1016/s0005-2728(98)00136-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- M Hippler
- Departments of Molecular Biology and Plant Biology, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva-4, Switzerland
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Kamlowski A, Altenberg-Greulich B, van der Est A, Zech SG, Bittl R, Fromme P, Lubitz W, Stehlik D. The Quinone Acceptor A1 in Photosystem I: Binding Site, and Comparison to QA in Purple Bacteria Reaction Centers. J Phys Chem B 1998. [DOI: 10.1021/jp9824611] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andreas Kamlowski
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany; European Molecular Biology Laboratory, Abt. Biocomputing, Meyerhofstr. 1, 69117 Heidelberg, Germany; and Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Brigitte Altenberg-Greulich
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany; European Molecular Biology Laboratory, Abt. Biocomputing, Meyerhofstr. 1, 69117 Heidelberg, Germany; and Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Arthur van der Est
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany; European Molecular Biology Laboratory, Abt. Biocomputing, Meyerhofstr. 1, 69117 Heidelberg, Germany; and Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Stephan G. Zech
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany; European Molecular Biology Laboratory, Abt. Biocomputing, Meyerhofstr. 1, 69117 Heidelberg, Germany; and Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Robert Bittl
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany; European Molecular Biology Laboratory, Abt. Biocomputing, Meyerhofstr. 1, 69117 Heidelberg, Germany; and Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Petra Fromme
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany; European Molecular Biology Laboratory, Abt. Biocomputing, Meyerhofstr. 1, 69117 Heidelberg, Germany; and Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Wolfgang Lubitz
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany; European Molecular Biology Laboratory, Abt. Biocomputing, Meyerhofstr. 1, 69117 Heidelberg, Germany; and Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Dietmar Stehlik
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany; European Molecular Biology Laboratory, Abt. Biocomputing, Meyerhofstr. 1, 69117 Heidelberg, Germany; and Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
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Schubert WD, Klukas O, Saenger W, Witt HT, Fromme P, Krauss N. A common ancestor for oxygenic and anoxygenic photosynthetic systems: a comparison based on the structural model of photosystem I. J Mol Biol 1998; 280:297-314. [PMID: 9654453 DOI: 10.1006/jmbi.1998.1824] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The 4 A structural model of photosystem I (PSI) has elucidated essential features of this protein complex. Inter alia, it demonstrates that the core proteins of PSI, PsaA and PsaB each consist of an N-terminal antenna-binding domain, and a C-terminal reaction center (RC)-domain. A comparison of the RC-domain of PSI and the photosynthetic RC of purple bacteria (PbRC), reveals significantly analogous structures. This provides the structural support for the hypothesis that the two RC-types (I and II) share a common evolutionary origin. Apart from a similar set of constituent cofactors of the electron transfer system, the analogous features include a comparable cofactor arrangement and a corresponding secondary structure motif of the RC-cores. Despite these analogies, significant differences are evident, particularly as regards the distances between and the orientation of individual cofactors, and the length and orientation of alpha-helices. Inferred roles of conserved amino acids are discussed for PSI, photosystem II (PSII), photosystem C (PSC, green sulfur bacteria) and photosystem H (PSH, heliobacteria). Significant sequence homology between the N-terminal, antenna-binding domains of the core proteins of type-I RCs, PsaA, PsaB, PscA and PshA (of PSI, PSC and PSH respectively) with the antenna-binding subunits CP43 and CP47 of PSII indicate that PSII has a modular structure comparable to that of PSI.
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Affiliation(s)
- W D Schubert
- Institut für Kristallographie, Freie Universität Berlin, Takustr. 6, Berlin, D-14195, Germany
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17
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Redding K, MacMillan F, Leibl W, Brettel K, Hanley J, Rutherford AW, Breton J, Rochaix JD. A systematic survey of conserved histidines in the core subunits of Photosystem I by site-directed mutagenesis reveals the likely axial ligands of P700. EMBO J 1998; 17:50-60. [PMID: 9427740 PMCID: PMC1170357 DOI: 10.1093/emboj/17.1.50] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The Photosystem I complex catalyses the transfer of an electron from lumenal plastocyanin to stromal ferredoxin, using the energy of an absorbed photon. The initial photochemical event is the transfer of an electron from the excited state of P700, a pair of chlorophylls, to a monomer chlorophyll serving as the primary electron acceptor. We have performed a systematic survey of conserved histidines in the last six transmembrane segments of the related polytopic membrane proteins PsaA and PsaB in the green alga Chlamydomonas reinhardtii. These histidines, which are present in analogous positions in both proteins, were changed to glutamine or leucine by site-directed mutagenesis. Double mutants in which both histidines had been changed to glutamine were screened for changes in the characteristics of P700 using electron paramagnetic resonance, Fourier transform infrared and visible spectroscopy. Only mutations in the histidines of helix 10 (PsaA-His676 and PsaB-His656) resulted in changes in spectroscopic properties of P700, leading us to conclude that these histidines are most likely the axial ligands to the P700 chlorophylls.
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Affiliation(s)
- K Redding
- Department of Molecular Biology, University of Geneva, 30, quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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18
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Pulsed EPR detection of light-generated nuclear coherences in photosynthetic reaction centers. Chem Phys Lett 1998. [DOI: 10.1016/s0009-2614(97)01331-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Diner BA. [23]Application of spectroscopic techniques to the Study of Photosystem II Mutations Engineered in Synechocystis and Chlamydomonas. Methods Enzymol 1998. [DOI: 10.1016/s0076-6879(98)97025-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Schubert WD, Klukas O, Krauss N, Saenger W, Fromme P, Witt HT. Photosystem I of Synechococcus elongatus at 4 A resolution: comprehensive structure analysis. J Mol Biol 1997; 272:741-69. [PMID: 9368655 DOI: 10.1006/jmbi.1997.1269] [Citation(s) in RCA: 224] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An improved structural model of the photosystem I complex from the thermophilic cyanobacterium Synechococcus elongatus is described at 4 A resolution. This represents the most complete model of a photosystem presently available, uniting both a photosynthetic reaction centre domain and a core antenna system. Most constituent elements of the electron transfer system have been located and their relative centre-to-centre distances determined at an accuracy of approximately 1 A. These include three pseudosymmetric pairs of Chla and three iron-sulphur centres, FX, FA and FB. The first pair, a Chla dimer, has been assigned to the primary electron donor P700. One or both Chla of the second pair, eC2 and eC'2, presumably functionally link P700 to the corresponding Chla of the third pair, eC3 and eC'3, which is assumed to constitute the spectroscopically-identified primary electron acceptor(s), A0, of PSI. A likely location of the subsequent phylloquinone electron acceptor, QK, in relation to the properties of the spectroscopically identified electron acceptor A1 is discussed. The positions of a total of 89 Chla, 83 of which constitute the core antenna system, are presented. The maximal centre-to-centre distance between antenna Chla is < or = 16 A; 81 Chla are grouped into four clusters comprising 21, 23, 17 and 20 Chla, respectively. Two "connecting" Chla are positioned to structurally (and possibly functionally) link the Chla of the core antenna to those of the electron transfer system. Thus the second and third Chla pairs of the electron transfer system may have a dual function both in energy transfer and electron transport. A total of 34 transmembrane and nine surface alpha-helices have been identified and assigned to the 11 subunits of the PSI complex. The connectivity of the nine C-terminal (seven transmembrane, two "surface") alpha-helices of each of the large core subunits PsaA and PsaB is described. The assignment of the amino acid sequence to the transmembrane alpha-helices is proposed and likely residues involved in co-ordinating the Chla of the electron transfer system discussed.
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Affiliation(s)
- W D Schubert
- Institut für Kristallographie, Freie Universität Berlin, Germany
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