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Accueil > Départements > Biochimie, Biophysique et Biologie Structurale > Alain BOUSSAC : Photosystème II

Photosystème II

Publications de l’équipe


  • A. Boussac, I. Ugur, A. Marion, M. Sugiura, V. R. I. Kaila, et A. W. Rutherford, « The low spin - high spin equilibrium in the S2-state of the water oxidizing enzyme », Biochimica Et Biophysica Acta, vol. 1859, nᵒ 5, p. 342-356, févr. 2018.
    Résumé : In Photosystem II (PSII), the Mn4CaO5-cluster of the active site advances through five sequential oxidation states (S0to S4) before water is oxidized and O2is generated. Here, we have studied the transition between the low spin (LS) and high spin (HS) configurations of S2using EPR spectroscopy, quantum chemical calculations using Density Functional Theory (DFT), and time-resolved UV-visible absorption spectroscopy. The EPR experiments show that the equilibrium between S2LSand S2HSis pH dependent, with a pKa ≈ 8.3 (n ≈ 4) for the native Mn4CaO5and pKa ≈ 7.5 (n ≈ 1) for Mn4SrO5. The DFT results suggest that exchanging Ca with Sr modifies the electronic structure of several titratable groups within the active site, including groups that are not direct ligands to Ca/Sr, e.g., W1/W2, Asp61, His332 and His337. This is consistent with the complex modification of the pKaupon the Ca/Sr exchange. EPR also showed that NH3addition reversed the effect of high pH, NH3-S2LSbeing present at all pH values studied. Absorption spectroscopy indicates that NH3is no longer bound in the S3TyrZstate, consistent with EPR data showing minor or no NH3-induced modification of S3and S0. In both Ca-PSII and Sr-PSII, S2HSwas capable of advancing to S3at low temperature (198 K). This is an experimental demonstration that the S2LSis formed first and advances to S3via the S2HSstate without detectable intermediates. We discuss the nature of the changes occurring in the S2LSto S2HStransition which allow the S2HSto S3transition to occur below 200 K. This work also provides a protocol for generating S3in concentrated samples without the need for saturating flashes.
    Mots-clés : B3S, DFT, EPR, Mn(4)CaO(5) cluster, Oxygen evolution, Photosystem II, PS2, Spin state.

  • J. - H. Chen, L. - J. Yu, A. Boussac, Z. - Y. Wang-Otomo, T. Kuang, et J. - R. Shen, « Properties and structure of a low-potential, penta-heme cytochrome c 552 from a thermophilic purple sulfur photosynthetic bacterium Thermochromatium tepidum », Photosynthesis Research, avr. 2018.
    Résumé : The thermophilic purple sulfur bacterium Thermochromatium tepidum possesses four main water-soluble redox proteins involved in the electron transfer behavior. Crystal structures have been reported for three of them: a high potential iron-sulfur protein, cytochrome c', and one of two low-potential cytochrome c 552 (which is a flavocytochrome c) have been determined. In this study, we purified another low-potential cytochrome c 552 (LPC), determined its N-terminal amino acid sequence and the whole gene sequence, characterized it with absorption and electron paramagnetic spectroscopy, and solved its high-resolution crystal structure. This novel cytochrome was found to contain five c-type hemes. The overall fold of LPC consists of two distinct domains, one is the five heme-containing domain and the other one is an Ig-like domain. This provides a representative example for the structures of multiheme cytochromes containing an odd number of hemes, although the structures of multiheme cytochromes with an even number of hemes are frequently seen in the PDB database. Comparison of the sequence and structure of LPC with other proteins in the databases revealed several characteristic features which may be important for its functioning. Based on the results obtained, we discuss the possible intracellular function of this LPC in Tch. tepidum.
    Mots-clés : B3S, Crystal structure, Cytochrome c, Electron transfer, Multiheme, PS2, Purple sulfur bacteria, Thermochromatium tepidum.

  • M. Nakamura, A. Boussac, et M. Sugiura, « Consequences of structural modifications in cytochrome b559 on the electron acceptor side of Photosystem II », Photosynthesis Research, mai 2018.
    Résumé : Cytb559 in Photosystem II is a heterodimeric b-type cytochrome. The subunits, PsbE and PsbF, consist each in a membrane α-helix. Mutants were previously designed and studied in Thermosynechococcus elongatus (Sugiura et al., Biochim Biophys Acta 1847:276-285, 2015) either in which an axial histidine ligand of the haem-iron was substituted for a methionine, the PsbE/H23M mutant in which the haem was lacking, or in which the haem environment was modified, the PsbE/Y19F and PsbE/T26P mutants. All these mutants remained active showing that the haem has no structural role provided that PsbE and PsbF subunits are present. Here, we have carried on the characterization of these mutants. The following results were obtained: (i) the Y19F mutation hardly affect the Em of Cytb559, whereas the T26P mutation converts the haem into a form with a Em much below 0 mV (so low that it is likely not reducible by QB-) even in an active enzyme; (ii) in the PsbE/H23M mutant, and to a less extent in PsbE/T26P mutant, the electron transfer efficiency from QA- to QB is decreased; (iii) the lower Em of the QA/QA- couple in the PsbE/H23M mutant correlates with a higher production of singlet oxygen; (iv) the superoxide and/or hydroperoxide formation was not increased in the PsbE/H23M mutant lacking the haem, whereas it was significantly larger in the PsbE/T26P. These data are discussed in view of the literature to discriminate between structural and redox roles for the haem of Cytb559 in the production of reactive oxygen species.
    Mots-clés : Acceptor side, B3S, Cytb 559, Haem axial ligand, Photosystem II, PS2, Redox.

  • D. J. Nürnberg, J. Morton, S. Santabarbara, A. Telfer, P. Joliot, L. A. Antonaru, A. V. Ruban, T. Cardona, E. Krausz, A. Boussac, A. Fantuzzi, et A. W. Rutherford, « Photochemistry beyond the red limit in chlorophyll f-containing photosystems », Science (New York, N.Y.), vol. 360, nᵒ 6394, p. 1210-1213, 2018.
    Résumé : Photosystems I and II convert solar energy into the chemical energy that powers life. Chlorophyll a photochemistry, using red light (680 to 700 nm), is near universal and is considered to define the energy "red limit" of oxygenic photosynthesis. We present biophysical studies on the photosystems from a cyanobacterium grown in far-red light (750 nm). The few long-wavelength chlorophylls present are well resolved from each other and from the majority pigment, chlorophyll a. Charge separation in photosystem I and II uses chlorophyll f at 745 nm and chlorophyll f (or d) at 727 nm, respectively. Each photosystem has a few even longer-wavelength chlorophylls f that collect light and pass excitation energy uphill to the photochemically active pigments. These photosystems function beyond the red limit using far-red pigments in only a few key positions.
    Mots-clés : B3S, PS2.


  • T. Motomura, M. Suga, R. Hienerwadel, A. Nakagawa, T. - L. Lai, W. Nitschke, T. Kuma, M. Sugiura, A. Boussac, et J. - R. Shen, « Crystal structure and redox properties of a novel cyanobacterial heme-protein with a His/Cys heme axial ligation and a per-arnt-sim (PAS)-like domain », The Journal of Biological Chemistry, avr. 2017.
    Résumé : Photosystem II (PSII) catalyzes the light-induced water oxidation leading to the generation of dioxygen indispensable for sustaining aerobic life on Earth. The PSII reaction center is composed of D1 and D2 proteins encoded by the psbA and psbD genes, respectively. In cyanobacteria, different psbA genes are present in the genome. The thermophilic cyanobacterium Thermosynechococcus elongatus contains 3 psbA genes, psbA1, psbA2 and psbA3 and a new c-type heme protein, Tll0287, was found to be expressed in a strain expressing the psbA2 gene only, but the structure and function of Tll0287 are unknown. Here we solved the crystal structure of Tll0287 at a 2.0 Å resolution. The overall structure of Tll0287 was found to be similar to some kinases and sensor proteins with a per-arnt-sim (PAS)-like domain, rather than to other c-type cytochromes. The 5(th) and 6(th) axial ligands for the heme were Cys and His, instead of the His/Met or His/His ligand pairs observed for most of the c-type hemes. The redox potential, E1/2, of Tll0287 was -255 ± 20 mV versus normal hydrogen electrode at pH values above 7.5. Below this pH value, the E1/2 increased by ≈57 mV/pH unit at 15°C, suggesting the involvement of a protonatable group with a pKred = 7.2 ± 0.3. Possible functions of Tll0287 as a redox sensor under micro-aerobic conditions or a cytochrome subunit of an H2S-oxidising system, are discussed in view of the environmental conditions in which psbA2 is expressed as well as phylogenetic analysis, structural and sequence homologies.
    Mots-clés : ACTIN, B3S, cytochrome, D1 protein, Heme, His-Cys heme axial coordination, PAS domain, PAS-like domain, photosynthesis, Photosystem II, PS2, Tll0287, x-ray crystallography.



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Publications 2011-2014

-  The effect of Ca2+/Sr2+ substitution on the electronic structure of the oxygen-evolving complex of photosystem II : A combined multi-frequency EPR, 55Mn-ENDOR and DFT study of the S2 state.
Cox, N., Rapatskiy, L., Su, J.-H., Pantazis, D. A., Sugiura, M., Kulik, L., Dorlet, P., Rutherford, A. W., Neese, F., Boussac, A., Lubitz, W., Messinger, J. (2011) J. Am. Chem. Soc. 133, 3635-3648.

-  The electronic structures of the S2 states of the oxygen-evolving complexes of Photosystem II in plants and cyanobacteria in the presence and absence of methanol.
Su, J.-H., Cox, N., Ames, W., Pantazis, D. A., Rapatskiy, L., Lohmiller, T., Kulik, L. V., Dorlet, P., Rutherford, A. W., Neese, F., Boussac, A., Lubitz, W., Messinger, J. (2011) Biochim. Biophys. Acta 1807, 829–840.

-  Ca2+ determines the entropy changes associated with the formation of transition states during water oxidation by Photosystem II.
Rappaport, F., Ishida, N., Sugiura, M., Boussac, A. (2011) Energ. Environ. Sci. 4, 2520-2524.

-  The semiquinone-iron complex of Photosystem II : EPR signals assigned to the low field edge of the ground state doublet of QA•-Fe2+ and QB•-Fe2+.
Sedoud, A., Cox, N., Sugiura, M., Lubitz, W., Boussac, A. Rutherford, A. W. (2011) Biochemistry 50, 6012–6021.

-  Deactivation processes in PsbA1-Photosystem II and PsbA3-Photosystem II under photoinhibitory conditions in the cyanobacterium Thermosynechococcus elongatus.
Ogami, S., Boussac, A., Sugiura, M. (2012) Biochim. Biophys. Acta 1817, 1322–1330.

-  Environment of TyrZ in Photosystem II from Thermosynechococcus elongatus in which PsbA2 is the D1 protein.
Sugiura, M. Ogami, S., Kusumi, M., Un, S., Rappaport, F., Boussac, A. (2012) J. Biol. Chem. 287, 13336–13347.

-  Probing the role of chloride in Photosystem II from Thermosynechococcus elongatus by exchanging chloride for iodide.
Boussac, A., Ishida, N., Sugiura, M., Rappaport, F. (2012) Biochim. Biophys. Acta 1817, 802–810.

-  Influence of the PsbA1/PsbA3 and Ca2+/Sr2+ or Cl–/Br– exchanges on the redox potential of the primary quinone QA in Photosystem II as revealed by spectroelectrochemistry.
Kato, Y., Shibamoto, T., Yamamoto, S., Watanabe, T., Ishida, N., Sugiura, M., Rappaport, F., Boussac, A. (2012) Biochim. Biophys. Acta 1817, 1998–2004.

-  Detection of the Water Binding Sites of the Oxygen-evolving Complex of Photosystem II Using W-band 17O ELDOR detected NMR Spectroscopy
Rapatskiy, L., Cox, N., Savitsky, A., Ames, W. M., Sander, J., Nowacyzk, M. M. Rögner, M., Boussac, A., Neese, F., Messinger, J., Lubitz, W. (2012) J. Am. Chem. Soc 134, 16619–16634.

-  The Rotavirus Nonstructural Protein NSP5 Coordinates a [2Fe-2S] Iron-Sulfur Cluster that Modulates Interaction with RNA
Martin, D., Charpilienne, A., Parent, A., Boussac, A., D’Autreaux, B., Poupon, J., Poncet, D. (2013) FASEB J. 27, 1074–1083.

-  Charge recombination in SnTyrZ•QA−• radical pairs in D1 protein variants of Photosystem II : Long range electron transfer in the Marcus inverted region.
Boussac, A. Rappaport, F., Brettel, K., Sugiura, M. (2013) J. Phys. Chem. B 117, 3308−3314.

-  The Tll0287 protein is a hemoprotein associated with the PsbA2-Photosystem II complex in Thermosynechococcus elongatus.
Boussac, A., Koyama, K., Sugiura, M. (2013) Biochim. Biophys. Acta 1827, 1174–1182.

-  EPR characterization of the ferrous nitrosyl complex formed within the oxygenase domain of NO-synthase.
Santolini, J., Maréchal, A., Boussac, A., Dorlet, P. (2013) ChemBioChem. 14, 1852–1857.

-  Ammonia binding to the oxygen-evolving complex of Photosystem II identifies the solvent-exchangeable μ-oxo of the manganese tetramer.
Pérez Navarro, M., Ames, W. M., Nilsson, H., Lohmiller, T., Pantazis, D. A., Rapatskiy, L., Nowaczyk, M. M., Neese, F., Boussac, A., Messinger, J., Lubitz, W., Cox, C. (2013) Proc. Natl. Acad. Sci. USA 110, 15561–15566.

-  Modification of the pheophytin redox potential in Thermosynechococcus elongatus Photosystem II with PsbA3 as D1.
Sugiura, M., Azami, C., Koyama, K., Rutherford, A.W., Rappaport, F., Boussac, A. (2014) Biochim. Biophys. Acta 1837, 139–148.

-  Crystal structure at 1.5 Å resolution of the PsbV2 cytochrome from the - cyanobacterium Thermosynechococcus elongatus.
Suga, M., Lai, T.-L., Sugiura, M., Shen, J.-R., Boussac, A. (2013) FEBS Lett. 513, 3267–3272.

-  Evidence for an unprecedented histidine hydroxyl modification on D2-His336 in Photosystem II of Thermosynechoccocus vulcanus and Thermosynechoccocus elongatus.
Sugiura, M., Koyama, K., Umena, Y., Kawakami, K., Shen, J.-R., Kamiya, N., Boussac, A. (2013) Biochemistry 52, 9426–9431.

-  Some Photosystem II properties depending on the D1 protein variants in Thermosynechococcus elongatus.
Sugiura, M., Boussac, A., (2014) Biochim. Biophys. Acta 1837, 1427–1434.

-  The S2 state of the oxygen-evolving complex of Photosystem II : a combined EPR and DFT study demonstrating a general electronic structure and ligand/substrate binding.
Lohmiller, T., Krewald, V., Pérez Navarro, M., Retegan, M., Rapatskiy, L., Nowaczyk, M. M., Boussac, A., Neese, F., Lubitz, W., Pantazis, D. A., Cox, N. (2014) Phys. Chem. Chem. Phys. 16, 11877–11892.

-  Substrate-water exchange in Photosystem II is arrested prior to dioxygen formation.
Nilsson, H., Rappaport, F., Boussac, A., Messinger, J. Nature Communications. 5, 4305..

-  Electronic structure of the oxygen evolving complex in photosystem II prior to O-O bond formation
Cox, N., Retegan, M., Neese, F., Pantazis, D.A., Boussac, A., Lubitz, W. (2014) Science 345, 804-808.

-  The D1-173 amino acid is a structural determinant of the critical interaction between D1-Tyr161 (TyrZ) and D1-His190 in Photosystem II
Sugiura, M., Ozaki, Y., Nakamura, M., Cox, N., Rappaport, F., Boussac, A., (2014) Biochim. Biophys. Acta 1837, 1922–1931.

-  Assembly of oxygen-evolving Photosystem II efficiently occurs with the apo-Cytb559 but the holo-Cytb559 accelerates the recovery of a functional enzyme upon photoinhibition.
Sugiura, M., Nakamura, M., Koyama, K., Boussac, A. (2015) Biochim. Biophys. Acta sous presse.

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