研究者詳細 - 沈　建仁

論文 - 沈　建仁

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A siphonous morphology affects light-harvesting modulation in the intertidal green macroalga Bryopsis corticulans (Ulvophyceae) 査読国際誌

Vasco Giovagnetti, Guangye Han, Maxwell A. Ware, Petra Ungerer, Xiaochun Qin, Wen-Da Wang, Tingyun Kuang, Jian-Ren Shen, Alexander V. Ruban

PLANTA 247 ( 6 ) 1293 - 1306 2018年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Main conclusion The macroalga Bryopsis corticulans relies on a sustained protective NPQ and a peculiar body architecture to efficiently adapt to the extreme light changes of intertidal shores.During low tides, intertidal algae experience prolonged high light stress. Efficient dissipation of excess light energy, measured as non-photochemical quenching (NPQ) of chlorophyll fluorescence, is therefore required to avoid photodamage. Light-harvesting regulation was studied in the intertidal macroalga Bryopsis corticulans, during high light and air exposure. Photosynthetic capacity and NPQ kinetics were assessed in different filament layers of the algal tufts and in intact chloroplasts to unravel the nature of NPQ in this siphonous green alga. We found that the morphology and pigment composition of the B. corticulans body provides functional segregation between surface sunlit filaments (protective state) and those that are underneath and undergo severe light attenuation (light-harvesting state). In the surface filaments, very high and sustained NPQ gradually formed. NPQ induction was triggered by the formation of transthylakoid proton gradient and independent of the xanthophyll cycle. PsbS and LHCSR proteins seem not to be active in the NPQ mechanism activated by this alga. Our results show that B. corticulans endures excess light energy pressure through a sustained protective NPQ, not related to photodamage, as revealed by the unusually quick restoration of photosystem II (PSII) function in the dark. This might suggest either the occurrence of transient PSII photoinactivation or a fast rate of PSII repair cycle.

DOI： 10.1007/s00425-018-2854-5

Fourier Transform Infrared Analysis of the S-State Cycle of Water Oxidation in the Microcrystals of Photosystem II 査読国際誌

Yuki Kato, Fusamichi Akita, Yoshiki Nakajima, Michihiro Suga, Yasufumi Umena, Jian-Ren Shen, Takumi Noguchi

JOURNAL OF PHYSICAL CHEMISTRY LETTERS 9 ( 9 ) 2121 - 2126 2018年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Photosynthetic water oxidation is performed in photosystem II (PSII) through a light-driven cycle of intermediates called S states (S-0-S-4) at the water oxidizing center. Time-resolved serial femtosecond crystallography (SFX) has recently been applied to the microcrystals of PSII to obtain the structural information on these intermediates. However, it remains unanswered whether the reactions efficiently proceed throughout the S-state cycle retaining the native structures of the intermediates in PSII crystals. We investigated the water oxidation reactions in the PSII microcrystals using flash-induced Fourier transform infrared (FTIR) difference spectroscopy. In comparison with the FTIR spectra in solution, it was shown that all of the metastable intermediates in the microcrystals retained their native structures, and the efficiencies of the S-state transitions remained relatively high, although those of the S-2 -> S-3 and S-3 -> S-0 transitions were slightly lowered possibly due to some restriction of water movement in the crystals.

DOI： 10.1021/acs.jpclett.8b00638

Vyacheslav (Slava) Klimov (1945-2017): A scientist par excellence, a great human being, a friend, and a Renaissance man 査読国際誌

Photosynth. Res. 136 ( 1 ) 1 - 16 2018年4月

Structure of photosynthetic LH1-RC supercomplex at 1.9 angstrom resolution 査読国際誌

Long-Jiang Yu, Michihiro Suga, Zheng-Yu Wang-Otomo, Jian-Ren Shen

NATURE 556 ( 7700 ) 209 - + 2018年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

Light-harvesting complex 1 (LH1) and the reaction centre (RC) form a membrane-protein supercomplex that performs the primary reactions of photosynthesis in purple photosynthetic bacteria. The structure of the LH1-RC complex can provide information on the arrangement of protein subunits and cofactors; however, so far it has been resolved only at a relatively low resolution. Here we report the crystal structure of the calcium-ion-bound LH1-RC supercomplex of Thermochromatium tepidum at a resolution of 1.9 angstrom. This atomic-resolution structure revealed several new features about the organization of protein subunits and cofactors. We describe the loop regions of RC in their intact states, the interaction of these loop regions with the LH1 subunits, the exchange route for the bound quinone QB with free quinone molecules, the transport of free quinones between the inside and outside of the LH1 ring structure, and the detailed calcium-ionbinding environment. This structure provides a solid basis for the detailed examination of the light reactions that occur during bacterial photosynthesis.

DOI： 10.1038/s41586-018-0002-9

Unique organization of photosystem I-light-harvesting supercomplex revealed by cryo-EM from a red alga 査読国際誌

Xiong Pi, Lirong Tian, Huai-En Dai, Xiaochun Qin, Lingpeng Cheng, Tingyun Kuang, Sen-Fang Sui, Jian-Ren Shen

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 115 ( 17 ) 4423 - 4428 2018年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATL ACAD SCIENCES

Photosystem I (PSI) is one of the two photosystems present in oxygenic photosynthetic organisms and functions to harvest and convert light energy into chemical energy in photosynthesis. In eukaryotic algae and higher plants, PSI consists of a core surrounded by variable species and numbers of light-harvesting complex (LHC)I proteins, forming a PSI-LHCI supercomplex. Here, we report cryo-EM structures of PSI-LHCR from the red alga Cyanidioschyzon merolae in two forms, one with three Lhcr subunits attached to the side, similar to that of higher plants, and the other with two additional Lhcr subunits attached to the opposite side, indicating an ancient form of PSI-LHCI. Furthermore, the red algal PSI core showed features of both cyanobacterial and higher plant PSI, suggesting an intermediate type during evolution from prokaryotes to eukaryotes. The structure of PsaO, existing in eukaryotic organisms, was identified in the PSI core and binds three chlorophylls a and may be important in harvesting energy and in mediating energy transfer from LHCII to the PSI core under state-2 conditions. Individual attaching sites of LHCRs with the core subunits were identified, and each Lhcr was found to contain 11 to 13 chlorophylls a and 5 zeaxanthins, which are apparently different from those of LHCs in plant PSI-LHCI. Together, our results reveal unique energy transfer pathways different from those of higher plant PSI-LHCI, its adaptation to the changing environment, and the possible changes of PSI-LHCI during evolution from prokaryotes to eukaryotes.

DOI： 10.1073/pnas.1722482115

Structured near-infrared Magnetic Circular Dichroism spectra of the Mn4CaO5 cluster of PSII in T. vulcanus are dominated by Mn(IV) d-d 'spin-flip' transitions 査読国際誌

Jennifer Morton, Maria Chrysina, Vincent S. J. Craig, Fusamichi Akita, Yoshiki Nakajima, Wolfgang Lubitz, Nicholas Cox, Jian-Ren Shen, Elmars Krausz

BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1859 ( 2 ) 88 - 98 2018年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Photosystem II passes through four metastable S-states in catalysing light-driven water oxidation. Variable temperature variable field (VTVH) Magnetic Circular Dichroism (MCD) spectra in PSII of Thermosynochococcus (T.) volcanos for each S-state are reported. These spectra, along with assignments, provide a new window into the electronic and magnetic structure of Mn4CaO5. VTVH MCD spectra taken in the S-2 state provide a clear g = 2, S = 1/2 paramagnetic characteristic, which is entirely consistent with that known by EPR. The three features, seen as positive (+) at 749 nm, negative (-) at 773 nm and (+) at 808 nm are assigned as (4)A -> E-2 spin-flips within the d(3) configuration of the Mn(IV) centres present. This assignment is supported by comparison(s) to spin flips seen in a range of Mn(IV) materials. S-3 exhibits a more intense (-) MCD peak at 764 nm and has a stronger MCD saturation characteristic. This S-3 MCD saturation behaviour can be accurately modelled using parameters taken directly from analyses of EPR spectra. We see no evidence for Mn(III) d-d absorption in the near-IR of any S-state. We suggest that Mn(IV)-based absorption may be responsible for the well-known near-IR induced changes induced in S-2 EPR spectra of T. volcanos and not Mn(Ill)-based, as has been commonly assumed. Through an analysis of the nephelauxetic effect, the excitation energy of S-state dependent spin-flips seen may help identify coordination characteristics and changes at each Mn(IV). A prospectus as to what more detailed S state dependent MCD studies promise to achieve is outlined.

DOI： 10.1016/j.bbabio.2017.10.004

Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction 査読国際誌

Melinda Magyar, Gabor Sipka, Laszlo Kovacs, Bettina Ughy, Qingjun Zhu, Guangye Han, Vladimir Spunda, Petar H. Lambrev, Jian-Ren Shen, Gyozo Garab

SCIENTIFIC REPORTS 8 ( 1 ) 2755 - 2755 2018年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

Photosystem II (PSII) catalyses the photoinduced oxygen evolution and, by producing reducing equivalents drives, in concert with PSI, the conversion of carbon dioxide to sugars. Our knowledge about the architecture of the reaction centre (RC) complex and the mechanisms of charge separation and stabilisation is well advanced. However, our understanding of the processes associated with the functioning of RC is incomplete: the photochemical activity of PSII is routinely monitored by chlorophyll-a fluorescence induction but the presently available data are not free of controversy. In this work, we examined the nature of gradual fluorescence rise of PSII elicited by trains of singleturnover saturating flashes (STSFs) in the presence of a PSII inhibitor, permitting only one stable charge separation. We show that a substantial part of the fluorescence rise originates from lightinduced processes that occur after the stabilisation of charge separation, induced by the first STSF; the temperature-dependent relaxation characteristics suggest the involvement of conformational changes in the additional rise. In experiments using double flashes with variable waiting times (Delta tau) between them, we found that no rise could be induced with zero or short Delta tau, the value of which depended on the temperature -revealing a previously unknown rate-limiting step in PSII.

DOI： 10.1038/s41598-018-21195-2

Purification of fully active and crystallizable photosystem II from thermophilic cyanobacteria 査読

Keisuke Kawakami, Jian-Ren Shen

Methods in Enzymology 613 1 - 16 2018年1月

記述言語：英語掲載種別：論文集(書籍)内論文出版者・発行元：Academic Press Inc.

Photosystem II (PSII) is a membrane protein complex which functions to catalyze light-induced water oxidation in oxygenic photosynthesis. Through the water-splitting reaction of PSII, light energy is converted into biologically useful chemical energy, and molecular oxygen is formed which transformed the atmosphere into an aerobic one and sustained aerobic life on the Earth. The PSII core complex from cyanobacteria consists of 17 transmembrane subunits and 3 extrinsic subunits with a total molecular mass of approximately 350 kDa per monomer, and PSII exists predominately in a dimeric form in vivo. This chapter describes the purification procedures leading to highly pure, homogenous, and highly active PSII core dimers from a thermophilic cyanobacterium, Thermosynechococcus vulcanus (T. vulcanus), that are used for successful crystallization and diffraction at atomic resolution. The purity and homogeneity of the PSII dimers thus obtained are characterized by absorption spectra, low-temperature fluorescence spectra, SDS-PAGE, clear native PAGE, blue native PAGE, gel filtration chromatography, and oxygen-evolving activity measurements. Finally, high-quality crystals obtained from the purified PSII dimers are shown.

DOI： 10.1016/bs.mie.2018.10.002

An aluminum/cobalt/iron/nickel alloy as a precatalyst for water oxidation 査読

Mohammad Mandi Najafpour, Somayeh Mehrabani, Robabeh Bagheri, Zhenlun Song, Jian-Ren Shen, Suleyman I. Allakhverdiev

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 43 ( 4 ) 2083 - 2090 2018年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Among different strategies, water splitting toward hydrogen production is a promising process to store energy from intermittent sources. However, the anodic water oxidation is a bottleneck for water splitting. In this paper, we report an aluminum/cobalt/iron/nickel alloy as a precatalyst for the electrochemical water oxidation. The alloy electrode contains different metal ions including cobalt, iron, and nickel which all are efficient for water oxidation is tested. We characterized this electrode using scanning electron microscopy, transmission electron microscopy, diffuse reflectance infrared Fourier transform spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical methods. After stabilization, the electrode shows an onset overpotential of 200.0 mV and affords a current density of 3.5 mA cm(-2) at an overpotential of 600.0 mV in KOH solution at pH 13. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ijhydene.2017.12.025

Probing structure-function relationships in early events in photosynthesis using a chimeric photocomplex 査読国際誌

Kenji V. P. Nagashima, Mai Sasaki, Kanako Hashimoto, Shinichi Takaichi, Sakiko Nagashima, Long-Jiang Yu, Yuto Abe, Kenta Gotou, Tomoaki Kawakami, Mizuki Takenouchi, Yuuta Shibuya, Akira Yamaguchi, Takashi Ohno, Jian-Ren Shen, Kazuhito Inoue, Michael T. Madigan, Yukihiro Kimura, Zheng-Yu Wang-Otomo

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 114 ( 41 ) 10906 - 10911 2017年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATL ACAD SCIENCES

The native core light-harvesting complex (LH1) from the thermophilic purple phototrophic bacterium Thermochromatium tepidum requires Ca2+ for its thermal stability and characteristic absorption maximum at 915 nm. To explore the role of specific amino acid residues of the LH1 polypeptides in Ca-binding behavior, we constructed a genetic system for heterologously expressing the Tch. tepidum LH1 complex in an engineered Rhodobacter sphaeroides mutant strain. This system contained a chimeric pufBALM gene cluster (pufBA from Tch. tepidum and pufLM from Rba. sphaeroides) and was subsequently deployed for introducing site-directed mutations on the LH1 polypeptides. All mutant strains were capable of phototrophic (anoxic/light) growth. The heterologously expressed Tch. tepidum wild-type LH1 complex was isolated in a reaction center (RC)-associated form and displayed the characteristic absorption properties of this thermophilic phototroph. Spheroidene (the major carotenoid in Rba. sphaeroides) was incorporated into the Tch. tepidum LH1 complex in place of its native spirilloxanthins with one carotenoid molecule present per alpha beta-subunit. The hybrid LH1-RC complexes expressed in Rba. sphaeroides were characterized using absorption, fluorescence excitation, and resonance Raman spectroscopy. Site-specific mutagenesis combined with spectroscopic measurements revealed that alpha-D49, beta-L46, and a deletion at position 43 of the alpha-polypeptide play critical roles in Ca binding in the Tch. tepidum LH1 complex; in contrast, alpha-N50 does not participate in Ca2+ coordination. These findings build on recent structural data obtained from a high-resolution crystallographic structure of the membrane integrated Tch. tepidum LH1-RC complex and have unambiguously identified the location of Ca2+ within this key antenna complex.

DOI： 10.1073/pnas.1703584114

Functional role of Lys residues of Psb31 in electrostatic interactions with diatom photosystem II 査読国際誌

Ryo Nagao, Takehiro Suzuki, Naoshi Dohmae, Jian-Ren Shen, Tatsuya Tomo

FEBS LETTERS 591 ( 20 ) 3259 - 3264 2017年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY

We recently revealed that positively charged amino acids of Psb31, an extrinsic subunit found in diatom photosystem II (PSII), are involved in electrostatic interactions with PSII intrinsic subunits. However, the molecular interactions of Psb31 with PSII remain unclear. Here, we report the functional contribution of Lys residues in the binding of Psb31 to PSII using site-directed mutants of Psb31. Each of the K33A, K39A, K54A, K56A, K57A, and K69A mutants exhibits decreased binding affinities to PSII concomitantly with decreases in the O-2 evolution activity. Conversely, each of the K24A, K76A, K80A, and K117A mutants functionally binds to PSII in a manner similar to wild-type Psb31. These results provide evidence that some Lys residues of Psb31 are responsible for electrostatic interactions with PSII.

DOI： 10.1002/1873-3468.12830

Isolation and characterization of PSI-LHCI super-complex and their sub-complexes from a red alga Cyanidioschyzon merolae 査読国際誌

Lirong Tian, Zheyi Liu, Fangjun Wang, Liangliang Shen, Jinghua Chen, Lijing Chang, Songhao Zhao, Guangye Han, Wenda Wang, Tingyun Kuang, Xiaochun Qin, Jian-Ren Shen

PHOTOSYNTHESIS RESEARCH 133 ( 1-3 ) 201 - 214 2017年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Photosystem I (PSI)-light-harvesting complex I (LHCI) super-complex and its sub-complexes PSI core and LHCI, were purified from a unicellular red alga Cyanidioschyzon merolae and characterized. PSI-LHCI of C. merolae existed as a monomer with a molecular mass of 580 kDa. Mass spectrometry analysis identified 11 subunits (PsaA, B, C, D, E, F, I, J, K, L, O) in the core complex and three LHCI subunits, CMQ142C, CMN234C, and CMN235C in LHCI, indicating that at least three Lhcr subunits associate with the red algal PSI core. PsaG was not found in the red algae PSI-LHCI, and we suggest that the position corresponding to Lhca1 in higher plant PSI-LHCI is empty in the red algal PSI-LHCI. The PSI-LHCI complex was separated into two bands on native PAGE, suggesting that two different complexes may be present with slightly different protein compositions probably with respective to the numbers of Lhcr subunits. Based on the results obtained, a structural model was proposed for the red algal PSI-LHCI. Furthermore, pigment analysis revealed that the C. merolae PSI-LHCI contained a large amount of zeaxanthin, which is mainly associated with the LHCI complex whereas little zeaxanthin was found in the PSI core. This indicates a unique feature of the carotenoid composition of the Lhcr proteins and may suggest an important role of Zea in the light-harvesting and photoprotection of the red algal PSI-LHCI complex.

DOI： 10.1007/s11120-017-0384-9

Large-scale QM/MM calculations of the CaMn4O5 cluster in the S-3 state of the oxygen evolving complex of photosystem II. Comparison between water-inserted and no water-inserted structures 査読国際誌

Mitsuo Shoji, Hiroshi Isobe, Takahito Nakajima, Yasuteru Shigeta, Michihiro Suga, Fusamichi Akita, Jian-Ren Shen, Kizashi Yamaguchi

FARADAY DISCUSSIONS 198 83 - 106 2017年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Large-scale QM/MM calculations were performed to elucidate an optimized geometrical structure of a CaMn4O5 cluster with and without water insertion in the S-3 state of the oxygen evolving complex (OEC) of photosystem II (PSII). The left (L)-opened structure was found to be stable under the assumption of no hydroxide anion insertion in the S-3 state, whereas the right (R)-opened structure became more stable if one water molecule is inserted to the Mn4Ca cluster. The optimized Mn-a(4)-Mn-d(1) distance determined by QM/MM was about 5.0 angstrom for the S-3 structure without an inserted hydroxide anion, but this is elongated by 0.2-0.3 angstrom after insertion. These computational results are discussed in relation to the possible mechanisms of O-O bond formation in water oxidation by the OEC of PSII.

DOI： 10.1039/c6fd00230g

Biological approaches to artificial photosynthesis, fundamental processes and theoretical approaches: general discussion 査読国際誌

Vincent Artero, Leif Hammarstrom, Fengtao Fan, Dong Ryeol Whang, Jose Martinez, Anthony Harriman, Takumi Noguchi, Joshua Karlsson, Peter Summers, Shigeru Itoh, Richard Cogdell, Alexander Kibler, Johannes Ehrmaier, Hitoshi Tamiaki, Etsuko Fujita, Seigo Shima, Shunya Yoshino, Haruo Inoue, Michael Wasielewski, Thomas Corry, Devens Gust, Flavia Cassiola, Hitoshi Ishida, Katsuhiko Takagi, Sang Ook Kang, Can Li, Licheng Sun, Hyunwoong Park, Hideki Hashimoto, Yutaka Amao, Eun Jin Son, Nobuo Kamiya, Jian-Ren Shen, Kizashi Yamaguchi

FARADAY DISCUSSIONS 198 147 - 168 2017年6月

Molecular catalysts for artificial photosynthesis: general discussion 査読国際誌

Mei Wang, Vincent Artero, Leif Hammarstrom, Jose Martinez, Joshua Karlsson, Devens Gust, Peter Summers, Charles Machan, Peter Brueggeller, Christopher D. Windle, Yosuke Kageshima, Richard Cogdell, Kristine Rodulfo Tolod, Alexander Kibler, Dogukan Hazar Apaydin, Etsuko Fujita, Johannes Ehrmaier, Seigo Shima, Elizabeth Gibson, Ferdi Karadas, Anthony Harriman, Haruo Inoue, Akihiko Kudo, Tomoaki Takayama, Michael Wasielewski, Flavia Cassiola, Masayuki Yagi, Hitoshi Ishida, Federico Franco, Sang Ook Kang, Daniel Nocera, Can Li, Fabio Di Fonzo, Hyunwoong Park, Licheng Sun, Tohru Setoyama, Young Soo Kang, Osamu Ishitani, Jian-Ren Shen, Ho-Jin Son, Shigeyuki Masaoka

FARADAY DISCUSSIONS 198 353 - 395 2017年6月

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 査読国際誌

Taiki Motomura, Michihiro Suga, Rainer Hienerwadel, Akiko Nakagawa, Thanh-Lan Lai, Wolfgang Nitschke, Takahiro Kuma, Miwa Sugiura, Alain Boussac, Jian-Ren Shen

JOURNAL OF BIOLOGICAL CHEMISTRY 292 ( 23 ) 9599 - 9612 2017年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

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 angstrom 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, E-1/2, 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 approximate to 57 mV/pH unit at 15 degrees C, suggesting the involvement of a protonatable group with a pK(red) = 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.

DOI： 10.1074/jbc.M116.746263

Ultrafast energy transfer within the photosystem II core complex 査読国際誌

Jie Pan, Andrius Gelzinis, Vladimir Chorosajev, Mikas Vengris, S. Seckin Senlik, Jian-Ren Shen, Leonas Valkunas, Darius Abramavicius, Jennifer P. Ogilvie

PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19 ( 23 ) 15356 - 15367 2017年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

We report 2D electronic spectroscopy on the photosystem II core complex (PSII CC) at 77 K under different polarization conditions. A global analysis of the high time-resolution 2D data shows rapid, sub-100 fs energy transfer within the PSII CC. It also reveals the 2D spectral signatures of slower energy equilibration processes occurring on several to hundreds of picosecond time scales that are consistent with previous work. Using a recent structure-based model of the PSII CC [Y. Shibata, S. Nishi, K. Kawakami, J. R. Shen and T. Renger, J. Am. Chem. Soc., 2013, 135, 6903], we simulate the energy transfer in the PSII CC by calculating auxiliary time-resolved fluorescence spectra. We obtain the observed sub-100 fs evolution, even though the calculated electronic energy shows almost no dynamics at early times. On the other hand, the electronic-vibrational interaction energy increases considerably over the same time period. We conclude that interactions with vibrational degrees of freedom not only induce population transfer between the excitonic states in the PSII CC, but also reshape the energy landscape of the system. We suggest that the experimentally observed ultrafast energy transfer is a signature of excitonic-polaron formation.

DOI： 10.1039/c7cp01673e

Light-induced structural changes and the site of O=O bond formation in PSII caught by XFEL 査読国際誌

Michihiro Suga, Fusamichi Akita, Michihiro Sugahara, Minoru Kubo, Yoshiki Nakajima, Takanori Nakane, Keitaro Yamashita, Yasufumi Umena, Makoto Nakabayashi, Takahiro Yamane, Takamitsu Nakano, Mamoru Suzuki, Tetsuya Masuda, Shigeyuki Inoue, Tetsunari Kimura, Takashi Nomura, Shinichiro Yonekura, Long-Jiang Yu, Tomohiro Sakamoto, Taiki Motomura, Jing-Hua Chen, Yuki Kato, Takumi Noguchi, Kensuke Tono, Yasumasa Joti, Takashi Kameshima, Takaki Hatsui, Eriko Nango, Rie Tanaka, Hisashi Naitow, Yoshinori Matsuura, Ayumi Yamashita, Masaki Yamamoto, Osamu Nureki, Makina Yabashi, Tetsuya Ishikawa, So Iwata, Jian-Ren Shen

NATURE 543 ( 7643 ) 131 - + 2017年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

Photosystem II (PSII) is a huge membrane-protein complex consisting of 20 different subunits with a total molecular mass of 350 kDa for a monomer. It catalyses light-driven water oxidation at its catalytic centre, the oxygen-evolving complex (OEC)(1-3). The structure of PSII has been analysed at 1.9 angstrom resolution by synchrotron radiation X-rays, which revealed that the OEC is a Mn4CaO5 cluster organized in an asymmetric, `distorted-chair' form(4). This structure was further analysed with femtosecond X-ray free electron lasers (XFEL), providing the `radiation damage-free'(5) structure. The mechanism of O=O bond formation, however, remains obscure owing to the lack of intermediate-state structures. Here we describe the structural changes in PSII induced by two-flash illumination at room temperature at a resolution of 2.35 angstrom using time-resolved serial femtosecond crystallography with an XFEL provided by the SPring-8 angstrom compact free-electron laser. An isomorphous difference Fourier map between the two-flash and dark-adapted states revealed two areas of apparent changes: around the QB/non-haem iron and the Mn4CaO5 cluster. The changes around the QB/non-haem iron region reflected the electron and proton transfers induced by the two-flash illumination. In the region around the OEC, a water molecule located 3.5 angstrom from the Mn4CaO5 cluster disappeared from the map upon two-flash illumination. This reduced the distance between another water molecule and the oxygen atom O4, suggesting that proton transfer also occurred. Importantly, the two-flash-minus-dark isomorphous difference Fourier map showed an apparent positive peak around O5, a unique mu 4-oxo-bridge located in the quasi-centre of Mn1 and Mn4 (refs 4,5). This suggests the insertion of a new oxygen atom (O6) close to O5, providing an O=O distance of 1.5 angstrom between these two oxygen atoms. This provides a mechanism for the O=O bond formation consistent with that proposed previously(6,7.)

DOI： 10.1038/nature21400

RESOLUTION BEYOND THE DIFFRACTION LIMIT 査読

Jian-Ren Shen, Stephen D. Bartlett, Amro Zayed, Abigail C. Allwood, Barbara Mazzolai, Virgilio Mattoli, Matthias Minderer, Christopher D. Harvey, Flavio Donato, Edvard I. Moser, M. Coleman Miller, Susan L. Williams

NATURE 540 ( 7634 ) 536 - 537 2016年12月

Probing the Lysine Proximal Microenvironments within Membrane Protein Complexes by Active Dimethyl Labeling and Mass Spectrometry 査読国際誌

Ye Zhou, Yue Wu, Mingdong Yao, Zheyi Liu, Jin Chen, Jun Chen, Lirong Tian, Guangye Han, Jian-Ren Shen, Fangjun Wang

ANALYTICAL CHEMISTRY 88 ( 24 ) 12060 - 12065 2016年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Positively charged lysines are crucial to maintaining the native structures of proteins and protein complexes by forming hydrogen bonds and electrostatic interactions with their proximal amino acid residues. However, it is still a challenge to develop an efficient method for probing the active proximal microenvironments of lysines without changing their biochemical/physical properties. Herein, we developed an active covalent labeling strategy combined with mass spectrometry to systematically probe the lysine proximal microenvironments within membrane protein complexes (similar to 700 kDa) with high throughput. Our labeling strategy has the advantages of high labeling efficiency and stability, preservation of the active charge states, as well as biological activity of the labeled proteins. In total, 121 lysines with different labeling levels were obtained for the photosystem II complexes from cyanobacteria, red algae, and spinach and provided important insights for understanding the conserved and nonconserved local structures of PSII complexes among evolutionarily divergent species that perform photosynthesis.

DOI： 10.1021/acs.analchem.6b02502

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