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Nakajima Y, Ugai-Amo N, Tone N, Nakagawa A, Iwai M, Ikeuchi M, Sugiura M, Suga M, Shen JR. Crystal structures of photosystem II from a cyanobacterium expressing psbA 2 in comparison to psbA 3 reveal differences in the D1 subunit. J Biol Chem 2022; 298:102668. [PMID: 36334624 PMCID: PMC9709244 DOI: 10.1016/j.jbc.2022.102668] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/27/2022] [Accepted: 10/30/2022] [Indexed: 11/07/2022] Open
Abstract
Three psbA genes (psbA1, psbA2, and psbA3) encoding the D1 subunit of photosystem II (PSII) are present in the thermophilic cyanobacterium Thermosynechococcus elongatus and are expressed differently in response to changes in the growth environment. To clarify the functional differences of the D1 protein expressed from these psbA genes, PSII dimers from two strains, each expressing only one psbA gene (psbA2 or psbA3), were crystallized, and we analyzed their structures at resolutions comparable to previously studied PsbA1-PSII. Our results showed that the hydrogen bond between pheophytin/D1 (PheoD1) and D1-130 became stronger in PsbA2- and PsbA3-PSII due to change of Gln to Glu, which partially explains the increase in the redox potential of PheoD1 observed in PsbA3. In PsbA2, one hydrogen bond was lost in PheoD1 due to the change of D1-Y147F, which may explain the decrease in stability of PheoD1 in PsbA2. Two water molecules in the Cl-1 channel were lost in PsbA2 due to the change of D1-P173M, leading to the narrowing of the channel, which may explain the lower efficiency of the S-state transition beyond S2 in PsbA2-PSII. In PsbA3-PSII, a hydrogen bond between D1-Ser270 and a sulfoquinovosyl-diacylglycerol molecule near QB disappeared due to the change of D1-Ser270 in PsbA1 and PsbA2 to D1-Ala270. This may result in an easier exchange of bound QB with free plastoquinone, hence an enhancement of oxygen evolution in PsbA3-PSII due to its high QB exchange efficiency. These results provide a structural basis for further functional examination of the three PsbA variants.
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Affiliation(s)
- Yoshiki Nakajima
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan
| | - Natsumi Ugai-Amo
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Naoki Tone
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Akiko Nakagawa
- Proteo-Science Research Center, Ehime University, Matsuyama, Japan
| | - Masako Iwai
- Graduate School and College of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Masahiko Ikeuchi
- Graduate School and College of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Miwa Sugiura
- Proteo-Science Research Center, Ehime University, Matsuyama, Japan
| | - Michihiro Suga
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan,Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan,For correspondence: Michihiro Suga; Jian-Ren Shen
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan,Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan,For correspondence: Michihiro Suga; Jian-Ren Shen
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2
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Sugiura M, Taniguchi T, Tango N, Nakamura M, Sellés J, Boussac A. Probing the role of arginine 323 of the D1 protein in photosystem II function. PHYSIOLOGIA PLANTARUM 2021; 171:183-199. [PMID: 32359083 DOI: 10.1111/ppl.13115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/22/2020] [Accepted: 04/24/2020] [Indexed: 06/11/2023]
Abstract
The Mn4 CaO5 cluster of photosystem II (PSII) advances sequentially through five oxidation states (S0 to S4 ). Under the enzyme cycle, two water molecules are oxidized, O2 is generated and four protons are released into the lumen. Umena et al. (2011) have proposed that, with other charged amino acids, the R323 residue of the D1 protein could contribute to regulate a proton egress pathway from the Mn4 CaO5 cluster and TyrZ via a proton channel identified from the 3D structure. To test this suggestion, a PsbA3/R323E site-directed mutant has been constructed and the properties of its PSII have been compared to those of the PsbA3-PSII by using EPR spectroscopy, polarography, thermoluminescence and time-resolved UV-visible absorption spectroscopy. Neither the oscillations with a period four nor the kinetics and S-state-dependent stoichiometry of the proton release were affected. However, several differences have been found: (1) the P680 + decay in the hundreds of ns time domain was much slower in the mutant, (2) the S2 QA - /DCMU and S3 QA - /DCMU radiative charge recombination occurred at higher temperatures and (3) the S0 TyrZ • , S1 TyrZ • , S2 TyrZ • split EPR signals induced at 4.2 K by visible light from the S0 TyrZ , S1 TyrZ , S2 TyrZ , respectively, and the (S2 TyrZ • )' induced by NIR illumination at 4.2 K of the S3 TyrZ state differed. It is proposed that the R323 residue of the D1 protein interacts with TyrZ likely via the H-bond network previously proposed to be a proton channel. Therefore, rather than participating in the egress of protons to the lumen, this channel could be involved in the relaxations of the H-bonds around TyrZ by interacting with the bulk, thus tuning the driving force required for TyrZ oxidation.
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Affiliation(s)
- Miwa Sugiura
- Proteo-Science Research Center, Ehime University, Matsuyama, 790-8577, Japan
| | - Tomonori Taniguchi
- Department of Chemistry, Graduate School of Science and Technology, Ehime University, Matsuyama, 790-8577, Japan
| | - Nanami Tango
- Department of Chemistry, Graduate School of Science and Technology, Ehime University, Matsuyama, 790-8577, Japan
| | - Makoto Nakamura
- Department of Chemistry, Graduate School of Science and Technology, Ehime University, Matsuyama, 790-8577, Japan
| | - Julien Sellés
- Institut de Biologie Physico-Chimique, UMR CNRS 7141 and Sorbonne Université, Paris, 75005, France
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3
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Mäusle SM, Abzaliyeva A, Greife P, Simon PS, Perez R, Zilliges Y, Dau H. Activation energies for two steps in the S 2→ S 3 transition of photosynthetic water oxidation from time-resolved single-frequency infrared spectroscopy. J Chem Phys 2020; 153:215101. [PMID: 33291916 DOI: 10.1063/5.0027995] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The mechanism of water oxidation by the Photosystem II (PSII) protein-cofactor complex is of high interest, but specifically, the crucial coupling of protonation dynamics to electron transfer (ET) and dioxygen chemistry remains insufficiently understood. We drove spinach-PSII membranes by nanosecond-laser flashes synchronously through the water-oxidation cycle and traced the PSII processes by time-resolved single-frequency infrared (IR) spectroscopy in the spectral range of symmetric carboxylate vibrations of protein side chains. After the collection of IR-transients from 100 ns to 1 s, we analyzed the proton-removal step in the S2 ⇒ S3 transition, which precedes the ET that oxidizes the Mn4CaOx-cluster. Around 1400 cm-1, pronounced changes in the IR-transients reflect this pre-ET process (∼40 µs at 20 °C) and the ET step (∼300 µs at 20 °C). For transients collected at various temperatures, unconstrained multi-exponential simulations did not provide a coherent set of time constants, but constraining the ET time constants to previously determined values solved the parameter correlation problem and resulted in an exceptionally high activation energy of 540 ± 30 meV for the pre-ET step. We assign the pre-ET step to deprotonation of a group that is re-protonated by accepting a proton from the substrate-water, which binds concurrently with the ET step. The analyzed IR-transients disfavor carboxylic-acid deprotonation in the pre-ET step. Temperature-dependent amplitudes suggest thermal equilibria that determine how strongly the proton-removal step is reflected in the IR-transients. Unexpectedly, the proton-removal step is only weakly reflected in the 1400 cm-1 transients of PSII core complexes of a thermophilic cyanobacterium (T. elongatus).
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Affiliation(s)
- Sarah M Mäusle
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Aiganym Abzaliyeva
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Paul Greife
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Philipp S Simon
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Rebeca Perez
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Yvonne Zilliges
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Holger Dau
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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4
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Sheridan KJ, Duncan EJ, Eaton-Rye JJ, Summerfield TC. The diversity and distribution of D1 proteins in cyanobacteria. PHOTOSYNTHESIS RESEARCH 2020; 145:111-128. [PMID: 32556852 DOI: 10.1007/s11120-020-00762-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
The psbA gene family in cyanobacteria encodes different forms of the D1 protein that is part of the Photosystem II reaction centre. We have identified a phylogenetically distinct D1 group that is intermediate between previously identified G3-D1 and G4-D1 proteins (Cardona et al. Mol Biol Evol 32:1310-1328, 2015). This new group contained two subgroups: D1INT, which was frequently in the genomes of heterocystous cyanobacteria and D1FR that was part of the far-red light photoacclimation gene cluster of cyanobacteria. In addition, we have identified subgroups within G3, the micro-aerobically expressed D1 protein. There are amino acid changes associated with each of the subgroups that might affect the function of Photosystem II. We show a phylogenetically broad range of cyanobacteria have these D1 types, as well as the genes encoding the G2 protein and chlorophyll f synthase. We suggest identification of additional D1 isoforms and the presence of multiple D1 isoforms in phylogenetically diverse cyanobacteria supports the role of these proteins in conferring a selective advantage under specific conditions.
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Affiliation(s)
- Kevin J Sheridan
- Department of Botany, University of Otago, Dunedin, New Zealand
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Elizabeth J Duncan
- Department of Biological Sciences, School of Biology, University of Leeds, Leeds, UK
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Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers. Proc Natl Acad Sci U S A 2020; 117:16373-16382. [PMID: 32601233 PMCID: PMC7368266 DOI: 10.1073/pnas.2000895117] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In photosynthetic reaction centers from purple bacteria (PbRC) and the water-oxidizing enzyme, photosystem II (PSII), charge separation occurs along one of the two symmetrical electron-transfer branches. Here we report the microscopic origin of the unidirectional charge separation, fully considering electron-hole interaction, electronic coupling of the pigments, and electrostatic interaction with the polarizable entire protein environments. The electronic coupling between the pair of bacteriochlorophylls is large in PbRC, forming a delocalized excited state with the lowest excitation energy (i.e., the special pair). The charge-separated state in the active branch is stabilized by uncharged polar residues in the transmembrane region and charged residues on the cytochrome c 2 binding surface. In contrast, the accessory chlorophyll in the D1 protein (ChlD1) has the lowest excitation energy in PSII. The charge-separated state involves ChlD1 •+ and is stabilized predominantly by charged residues near the Mn4CaO5 cluster and the proceeding proton-transfer pathway. It seems likely that the acquirement of water-splitting ability makes ChlD1 the initial electron donor in PSII.
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6
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Boussac A, Sellés J, Sugiura M. What can we still learn from the electrochromic band-shifts in Photosystem II? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148176. [PMID: 32061653 DOI: 10.1016/j.bbabio.2020.148176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 01/29/2020] [Accepted: 02/10/2020] [Indexed: 11/17/2022]
Abstract
Electrochromic band-shifts have been investigated in Photosystem II (PSII) from Thermosynechoccocus elongatus. Firstly, by using Mn-depleted PsbA1-PSII and PsbA3-PSII in which the QX absorption of PheD1 differs, a band-shift in the QX region of PheD2 centered at ~ 544 nm has been identified upon the oxidation, at pH 8.6, of TyrD. In contrast, a band-shift due to the formation of either QA•- or TyrZ• is observed in PsbA3-PSII at ~ 546 nm, as expected with E130 H-bonded to PheD1 and at ~ 544 nm as expected with Q130 H-bonded to PheD1. Secondly, electrochromic band-shifts in the Chla Soret region have been measured in O2-evolving PSII in PsbA3-PSII, in the PsbA3/H198Q mutant in which the Soret band of PD1 is blue shifted and in the PsbA3/T179H mutant. Upon TyrZ•QA•- formation the Soret band of PD1 is red shifted and the Soret band of ChlD1 is blue shifted. In contrast, only PD1 undergoes a detectable S-state dependent electrochromism. Thirdly, the time resolved S-state dependent electrochromism attributed to PD1 is biphasic for all the S-state transitions except for S1 to S2, and shows that: i) the proton release in S0 to S1 occurs after the electron transfer and ii) the proton release and the electron transfer kinetics in S2 to S3, in T. elongatus, are significantly faster than often considered. The nature of S2TyrZ• is discussed in view of the models in the literature involving intermediate states in the S2 to S3 transition.
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Affiliation(s)
- Alain Boussac
- I(2)BC, CNRS UMR 9198, CEA Saclay, 91191 Gif-sur-Yvette, France.
| | - Julien Sellés
- Institut de Biologie Physico-Chimique, CNRS UMR 7141 and Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Miwa Sugiura
- Proteo-Science Research Center and Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
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7
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de Lichtenberg C, Messinger J. Substrate water exchange in the S2 state of photosystem II is dependent on the conformation of the Mn4Ca cluster. Phys Chem Chem Phys 2020; 22:12894-12908. [DOI: 10.1039/d0cp01380c] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The structural flexibility of the Mn4Ca cluster in photosystem II supports the exchange of the central O5 bridge.
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8
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Boussac A. Temperature dependence of the high-spin S2 to S3 transition in Photosystem II: Mechanistic consequences. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:508-518. [DOI: 10.1016/j.bbabio.2019.05.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 02/08/2023]
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9
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Probing the role of Valine 185 of the D1 protein in the Photosystem II oxygen evolution. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1259-1273. [DOI: 10.1016/j.bbabio.2018.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/03/2018] [Accepted: 10/14/2018] [Indexed: 11/23/2022]
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10
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The low spin - high spin equilibrium in the S2-state of the water oxidizing enzyme. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:342-356. [DOI: 10.1016/j.bbabio.2018.02.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 02/21/2018] [Accepted: 02/24/2018] [Indexed: 11/17/2022]
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11
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Motomura T, Suga M, Hienerwadel R, Nakagawa A, Lai TL, Nitschke W, Kuma T, Sugiura M, Boussac A, Shen JR. 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. J Biol Chem 2017; 292:9599-9612. [PMID: 28428249 DOI: 10.1074/jbc.m116.746263] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 04/17/2017] [Indexed: 01/05/2023] Open
Abstract
Photosystem II catalyzes light-induced water oxidation leading to the generation of dioxygen indispensable for sustaining aerobic life on Earth. The Photosystem II reaction center is composed of D1 and D2 proteins encoded by psbA and psbD genes, respectively. In cyanobacteria, different psbA genes are present in the genome. The thermophilic cyanobacterium Thermosynechococcus elongatus contains three 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-like domain rather than to other c-type cytochromes. The fifth and sixth 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, E½, of Tll0287 was -255 ± 20 mV versus normal hydrogen electrode at pH values above 7.5. Below this pH value, the E½ 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 microaerobic conditions or a cytochrome subunit of an H2S-oxidizing system are discussed in view of the environmental conditions in which psbA2 is expressed, as well as phylogenetic analysis, structural, and sequence homologies.
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Affiliation(s)
- Taiki Motomura
- From the Department of Picobiology, Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan.,the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Michihiro Suga
- the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Rainer Hienerwadel
- the Laboratoire de Génétique et Biophysique des Plantes, UMR 7265, CNRS-CEA-Aix-Marseille Université, Faculté des Sciences de Luminy, 13288 Marseille, France
| | - Akiko Nakagawa
- the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.,the Proteo-Science Research Center, Ehime University, Ehime 790-8577, Japan
| | - Thanh-Lan Lai
- iBiTec-S, SB2SM, CNRS UMR 9198, CEA Saclay, 91191 Gif-sur-Yvette, France, and
| | - Wolfgang Nitschke
- the Laboratoire de Bioénergétique et Ingénierie des Protéines, CNRS UMR 7281, 13402 Marseille Cedex 20, France
| | - Takahiro Kuma
- the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Miwa Sugiura
- the Proteo-Science Research Center, Ehime University, Ehime 790-8577, Japan
| | - Alain Boussac
- iBiTec-S, SB2SM, CNRS UMR 9198, CEA Saclay, 91191 Gif-sur-Yvette, France, and
| | - Jian-Ren Shen
- From the Department of Picobiology, Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan, .,the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
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12
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Nakamura S, Ota K, Shibuya Y, Noguchi T. Role of a Water Network around the Mn4CaO5 Cluster in Photosynthetic Water Oxidation: A Fourier Transform Infrared Spectroscopy and Quantum Mechanics/Molecular Mechanics Calculation Study. Biochemistry 2016; 55:597-607. [DOI: 10.1021/acs.biochem.5b01120] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Shin Nakamura
- Division
of Material Science,
Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Kai Ota
- Division
of Material Science,
Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yuichi Shibuya
- Division
of Material Science,
Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- Division
of Material Science,
Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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13
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Boussac A, Rutherford AW, Sugiura M. Electron transfer pathways from the S2-states to the S3-states either after a Ca2+/Sr2+ or a Cl-/I- exchange in Photosystem II from Thermosynechococcus elongatus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:576-86. [PMID: 25843552 DOI: 10.1016/j.bbabio.2015.03.006] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 03/25/2015] [Accepted: 03/29/2015] [Indexed: 01/12/2023]
Abstract
The site for water oxidation in Photosystem II (PSII) goes through five sequential oxidation states (S0 to S4) before O2 is evolved. It consists of a Mn4CaO5-cluster close to a redox-active tyrosine residue (YZ). Cl- is also required for enzyme activity. By using EPR spectroscopy it has been shown that both Ca2+/Sr2+ exchange and Cl-/I- exchange perturb the proportions of centers showing high (S=5/2) and low spin (S=1/2) forms of the S2-state. The S3-state was also found to be heterogeneous with: i) a S=3 form that is detectable by EPR and not sensitive to near-infrared light; and ii) a form that is not EPR visible but in which Mn photochemistry occurs resulting in the formation of a (S2YZ)' split EPR signal upon near-infrared illumination. In Sr/Cl-PSII, the high spin (S=5/2) form of S2 shows a marked heterogeneity with a g=4.3 form generated at low temperature that converts to a relaxed form at g=4.9 at higher temperatures. The high spin g=4.9 form can then progress to the EPR detectable form of S3 at temperatures as low as 180K whereas the low spin (S=1/2) S2-state can only advance to the S3 state at temperatures≥235 K. Both of the two S2 configurations and the two S3 configurations are each shown to be in equilibrium at ≥235 K but not at 198 K. Since both S2 configurations are formed at 198 K, they likely arise from two specific populations of S1. The existence of heterogeneous populations in S1, S2 and S3 states may be related to the structural flexibility associated with the positioning of the oxygen O5 within the cluster highlighted in computational approaches and which has been linked to substrate exchange. These data are discussed in the context of recent in silico studies of the electron transfer pathways between the S2-state(s) and the S3-state(s).
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Affiliation(s)
- Alain Boussac
- I(2)BC, CNRS UMR 9198, CEA Saclay, 91191 Gif-sur-Yvette, France.
| | | | - Miwa Sugiura
- Proteo-Science Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; Department of Chemistry, Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; PRESTO, Japan Science and Technology Agency (JST), 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan
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14
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Vogt L, Vinyard DJ, Khan S, Brudvig GW. Oxygen-evolving complex of Photosystem II: an analysis of second-shell residues and hydrogen-bonding networks. Curr Opin Chem Biol 2015; 25:152-8. [DOI: 10.1016/j.cbpa.2014.12.040] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 12/20/2014] [Accepted: 12/25/2014] [Indexed: 12/22/2022]
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15
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Sugiura M, Nakamura M, Koyama K, Boussac A. 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. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:276-285. [PMID: 25481108 DOI: 10.1016/j.bbabio.2014.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 11/17/2014] [Accepted: 11/26/2014] [Indexed: 10/24/2022]
Abstract
Cytb559 in Photosystem II is a heterodimeric b-type cytochrome. The subunits, PsbE and PsbF, consist each in a membrane α-helix. Roles for Cytb559 remain elusive. In Thermosynechococcus elongatus, taking advantage of the robustness of the PSII variant with PsbA3 as the D1 subunit (WT*3), 4 mutants were designed hoping to get mutants nevertheless the obligatory phototrophy of this cyanobacterium. In two of them, an axial histidine ligand of the haem-iron was substituted for either a methionine, PsbE/H23M, which could be potentially a ligand or for an alanine, PsbE/H23A, which cannot. In the other mutants, PsbE/Y19F and PsbE/T26P, the environment around PsbE/H23 was expected to be modified. From EPR, MALDI-TOF and O2 evolution activity measurements, the following results were obtained: Whereas the PsbE/H23M and PsbE/H23A mutants assemble only an apo-Cytb559 the steady-state level of active PSII was comparable to that in WT*3. The lack of the haem or, in PsbE/T26P, conversion of the high-potential into a lower potential form, slowed-down the recovery rate of the O2 activity after high-light illumination but did not affect the photoinhibition rate. This resulted in the following order for the steady-state level of active PSII centers under high-light conditions: PsbE/H23M≈PsbE/H23A<< PsbE/Y19F≤PsbE/T26P≤WT*3. These data show i) that the haem has no structural role provided that PsbE and PsbF are present, ii) a lack of correlation between the rate of photoinhibition and the Em of the haem and iii) that the holo-Cytb559 favors the recovery of a functional enzyme upon photoinhibition.
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Affiliation(s)
- Miwa Sugiura
- Proteo-Science Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; Department of Chemistry, Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; PRESTO, Japan Science and Technology Agency (JST), 4-1-8, Honcho, Kawauchi, Saitama 332-0012, Japan.
| | - Makoto Nakamura
- Department of Chemistry, Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Kazumi Koyama
- Proteo-Science Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Alain Boussac
- iBiTec-S, CNRS UMR 8221, CEA Saclay, 91191 Gif-sur-Yvette, France.
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