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Miwa Sugiura - One of the best experts on this subject based on the ideXlab platform.
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photochemistry in photosystem II from Thermosynechococcus elongatus induced by visible and near-infrared light
2020Co-Authors: Alain Boussac, Miwa Sugiura, A. William RutherfordAbstract:showed that metalloradical states, probably arising from the Mn4 cluster interacting with TyrZ % , can be trapped by illumination of the S0 ,S 1 and S2 states at cryogenic temperatures. The EPR signals reported were attributed to S0TyrZ % ,S 1TyrZ % and S2TyrZ % , respectively. The equivalent states were examined here by EPR in PSII isolated from Thermosynechococcus elongatus with either Sr or Ca associated with the Mn4 cluster. In order to avoid spectral contributions from the second tyrosyl radical, TyrD % , PSII was used in which Tyr160 of D2 was replaced by phenylalanine. We report that the metalloradical signals attributed to TyrZ % interacting with the Mn cluster in S0 ,S 1 ,S 2 and also probably the S3 states are all affected by the presence of Sr. Ca/Sr exchange also affects the non-haem
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new insights on chld1 function in photosystem ii from site directed mutants of d1 t179 in Thermosynechococcus elongatus
Biochimica et Biophysica Acta, 2019Co-Authors: Yuki Takegawa, Alain Boussac, William A Rutherford, Takumi Noguchi, Makoto Nakamura, Shin Nakamura, Julien Selles, Miwa SugiuraAbstract:The monomeric chlorophyll, Chl(D1), which is located between the PD1PD2 chlorophyll pair and the pheophytin, Pheo(D1), is the longest wavelength chlorophyll in the heart of Photosystem II and is thought to be the primary electron donor. Its central Mg2+ is liganded to a water molecule that is H-bonded to D1/T179. Here, two site-directed mutants, D1/T179H and D1/T179V, were made in the thermophilic cyanobacterium, Thermosynechococcus elongatus, and characterized by a range of biophysical techniques. The Mn4CaO5 cluster in the water-splitting site is fully active in both mutants. Changes in thermoluminescence indicate that i) radiative recombination occurs via the repopulation of *Chl(D1) itself; ii) non-radiative charge recombination reactions appeared to be faster in the T179H-PSII; and iii) the properties of PD1PD2 were unaffected by this mutation, and consequently iv) the immediate precursor state of the radiative excited state is the Chl(D1)(+)Pheo(D1)(-) radical pair. Chlorophyll bleaching due to high intensity illumination correlated with the amount of O-1(2) generated. Comparison of the bleaching spectra with the electrochromic shifts attributed to Chl(D1) upon Q(A)(-) formation, indicates that in the T179H-PSII and in the WT*3-PSII, the Chl(D1) itself is the chlorophyll that is first damaged by O-1(2), whereas in the T179V-PSII a more red chlorophyll is damaged, the identity of which is discussed. Thus, Chl(D1) appears to be one of the primary damage site in recombination-mediated photoinhibition. Finally, changes in the absorption of Chl(D1) very likely contribute to the well-known electrochromic shifts observed at similar to 430 nm during the S-state cycle.
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variants of photosystem ii d1 protein in Thermosynechococcus elongatus
Research on Chemical Intermediates, 2014Co-Authors: Miwa Sugiura, Alain BoussacAbstract:Cyanobacteria have several psbA genes encoding PsbA, the D1 reaction center protein of the photosystem II (PSII) complex which bears, with PsbD, the D2 protein, most of the cofactors involved in electron-transfer reactions. The thermophilic cyanobacterium Thermosynechococcus elongatus has three psbA genes differently expressed depending on the environmental conditions. Among the 344 residues constituting each of the three possible PsbA variants there are 21 substitutions between PsbA1 and PsbA3, 31 between PsbA1 and PsbA2, and 27 between PsbA2 and PsbA3. In this review, we briefly summarize the changes already identified in the properties of the redox cofactors depending on the D1 variant constituting PSII in T. elongatus.
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some photosystem ii properties depending on the d1 protein variants in Thermosynechococcus elongatus
Biochimica et Biophysica Acta, 2014Co-Authors: Miwa Sugiura, Alain BoussacAbstract:Abstract Cyanobacteria have multiple psbA genes encoding PsbA, the D1 reaction center protein of the Photosystem II complex which bears together with PsbD, the D2 protein, most of the cofactors involved in electron transfer reactions. The thermophilic cyanobacterium Thermosynechococcus elongatus has three psbA genes differently expressed depending on the environmental conditions. Among the 344 residues constituting each of the 3 possible PsbA variants there are 21 substitutions between PsbA1 and PsbA3, 31 between PsbA1 and PsbA2 and 27 between PsbA2 and PsbA3. In this review, we summarize the changes already identified in the properties of the redox cofactors depending on the D1 variant constituting Photosystem II in T. elongatus . This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: Keys to Produce Clean Energy.
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modification of the pheophytin redox potential in Thermosynechococcus elongatus photosystem ii with psba3 as d1
Biochimica et Biophysica Acta, 2014Co-Authors: Miwa Sugiura, William A Rutherford, Fabrice Rappaport, Chizuko Azami, Kazumi Koyama, Alain BoussacAbstract:Abstract In Photosystem II (PSII) of the cyanobacterium Thermosynechococcus elongatus, glutamate 130 in the high-light variant of the D1-subunit (PsbA3) was changed to glutamine in a strain lacking the two other genes for D1, psbA1 and psbA2. The resulting PSII (PsbA3/Glu130Gln) was compared with those from the “native” high-light (PsbA3-PSII) and low-light (PsbA1-PSII) variants, which differ by 21 amino acid including Glu130Gln. H-bonding from D1-Glu130Gln to the primary electron acceptor, PheophytinD1 (PheoD1), is known to affect the Em of the PheoD1/PheoD1− couple. The Gln130 mutation here had little effect on water splitting, charge accumulation and photosensitivity but did slow down S2QA− charge recombination and up-shift the thermoluminescence while increasing its yield. These changes were consistent with a ≈ − 30 mV shift of the PheoD1/PheoD1− Em, similar to earlier single site-mutation results from other species and double the ≈ − 17 mV shift seen for PsbA1-PSII versus PsbA3-PSII. This is attributed to the influence of the other 20 amino-acids that differ in PsbA3. A computational model for simulating S2QA− recombination matched the experimental trend: the S2QA− recombination rate in PsbA1-PSII differed only slightly from that in PsbA3-PSII, while in Glu130-PsbA3-PSII there was a more pronounced slowdown of the radical pair decay. The simulation predicted a major effect of the PheoD1/PheoD1− potential on 1O2 yield (~ 60% in PsbA1-PSII, ~ 20% in PsbA3-PSII and ~ 7% in Gln130-PsbA3-PSII), reflecting differential sensitivities to high light.
Masahiko Ikeuchi - One of the best experts on this subject based on the ideXlab platform.
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cloning expression crystallization and preliminary x ray studies of the ferredoxin nad p reductase from the thermophilic cyanobacterium Thermosynechococcus elongatus bp 1
Acta Crystallographica Section F-structural Biology and Crystallization Communications, 2012Co-Authors: Pasqual Liauw, Masahiko Ikeuchi, Marta J Kopczak, Tomohiro Mashiba, Katrin Wiegand, Norifumi Muraki, Hisako Kubota, Yusuke Kawano, Toshiharu Hase, Matthias RognerAbstract:Ferredoxin–NADP+ reductase (FNR) is a flavoenzyme that catalyses the reduction of NADP+ in the final step of the photosynthetic electron-transport chain. FNR from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1 (TeFNR) contains an additional 9 kDa domain at its N-terminus relative to chloroplastic FNRs and is more thermostable than those from mesophilic cyanobacteria. With the aim of understanding the structural basis of the thermostability of TeFNR and assigning a structural role to the small additional domain, the gene encoding TeFNR with and without an additional domain was engineered for heterologous expression and the recombinant proteins were purified and crystallized. Crystals of TeFNR without the additional domain belonged to space group P21, with unit-cell parameters a = 55.05, b = 71.66, c = 89.73 A, α = 90, β = 98.21, γ = 90°.
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Cloning, expression, crystallization and preliminary X-ray studies of the ferredoxin-NAD(P)+ reductase from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1.
Acta Crystallographica Section F-structural Biology and Crystallization Communications, 2012Co-Authors: Pasqual Liauw, Masahiko Ikeuchi, Marta J Kopczak, Tomohiro Mashiba, Katrin Wiegand, Norifumi Muraki, Hisako Kubota, Yusuke Kawano, Toshiharu Hase, Matthias RognerAbstract:Ferredoxin–NADP+ reductase (FNR) is a flavoenzyme that catalyses the reduction of NADP+ in the final step of the photosynthetic electron-transport chain. FNR from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1 (TeFNR) contains an additional 9 kDa domain at its N-terminus relative to chloroplastic FNRs and is more thermostable than those from mesophilic cyanobacteria. With the aim of understanding the structural basis of the thermostability of TeFNR and assigning a structural role to the small additional domain, the gene encoding TeFNR with and without an additional domain was engineered for heterologous expression and the recombinant proteins were purified and crystallized. Crystals of TeFNR without the additional domain belonged to space group P21, with unit-cell parameters a = 55.05, b = 71.66, c = 89.73 A, α = 90, β = 98.21, γ = 90°.
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deletion of psbj leads to accumulation of psb27 psb28 photosystem ii complexes in Thermosynechococcus elongatus
Biochimica et Biophysica Acta, 2012Co-Authors: Marc M Nowaczyk, Masahiko Ikeuchi, Katharina Krause, Maren Mieseler, Anika Sczibilanski, Matthias RognerAbstract:Abstract The life cycle of Photosystem II (PSII) is embedded in a network of proteins that guides the complex through biogenesis, damage and repair. Some of these proteins, such as Psb27 and Psb28, are involved in cofactor assembly for which they are only transiently bound to the preassembled complex. In this work we isolated and analyzed PSII from a Δ psbJ mutant of the thermophilic cyanobacterium Thermosynechococcus elongatus . From the four different PSII complexes that could be separated the most prominent one revealed a monomeric Psb27–Psb28 PSII complex with greatly diminished oxygen-evolving activity. The MALDI-ToF mass spectrometry analysis of intact low molecular weight subunits ( 15 N labeled PsbA3-specific peptides indicated the complete replacement of PsbA1 by the stress copy PsbA3 in the mutant, even under standard growth conditions (50 μmol photons m − 2 s − 1 ). This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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the psbk subunit is required for the stable assembly and stability of other small subunits in the psii complex in the thermophilic cyanobacterium Thermosynechococcus elongatus bp 1
Plant and Cell Physiology, 2010Co-Authors: Masako Iwai, Takehiro Suzuki, Naoshi Dohmae, Yasunori Inoue, Akiko Kamiyama, Isamu Sakurai, Masahiko IkeuchiAbstract:: PsbK is a small membrane protein of the PSII core complex and is highly conserved from cyanobacteria to plants. Here, we studied its role in the thermophilic cyanobacterium, Thermosynechococcus elongatus BP-1, by focusing on a psbK disruptant with hexahistidine-tagged CP47. The psbK disruptant showed photoautotrophic growth comparable with that of the wild type under a wide range of light conditions. The mutant PSII complex retained the oxygen-evolving activity with a unique modification of the acceptor Q(B) site. N-terminal sequencing revealed that Ycf12 and PsbZ proteins were lost in the PSII complex prepared from the mutant. Immunoblotting detected reduced accumulation of PsbZ in the mutant thylakoid. These results suggest that PsbK is required not only for association of PsbZ and Ycf12 with the isolated PSII complex but also for the stabilization of PsbZ in the thylakoid membrane.
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acceleration of electron transfer induced fluorescence quenching upon conversion to the signaling state in the blue light receptor tepixd from Thermosynechococcus elongatus
Journal of Physical Chemistry B, 2009Co-Authors: Yutaka Shibata, Masahiko Ikeuchi, Yoshimasa Fukushima, Koji Okajima, Yoshiya Murai, Yosuke Satoh, Shigeru ItohAbstract:TePixD is a blue light using flavin (BLUF) protein of a thermophilic cyanobacterium, Thermosynechococcus elongatus. The fluorescence dynamics of TePixD was observed for the first time in both its dark-adapted and signaling (red-shifted) forms with a 200-fs time resolution. The fluorescence up-conversion setup was used in the time region up to 60 ps, and the streak-camera setup was used in the time region up to 1 ns. To avoid the accumulation of the red-shifted form by the exciting laser irradiation, the sample solution was circulated using a diaphragm pump. A handmade flow cuvette with a small cross section was used to achieve a fast flow of the solution in the excited region. The fluorescence decay times were unequivocally determined to be 13.6 and 114 ps for the dark-adapted form and 1.37 ps for the red-shifted form. The double-exponential fluorescence decay in the dark-adapted form suggested the coexistence of two conformations that have the 13.6- and 114-ps decay components, respectively. The single-e...
Alain Boussac - One of the best experts on this subject based on the ideXlab platform.
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photochemistry in photosystem II from Thermosynechococcus elongatus induced by visible and near-infrared light
2020Co-Authors: Alain Boussac, Miwa Sugiura, A. William RutherfordAbstract:showed that metalloradical states, probably arising from the Mn4 cluster interacting with TyrZ % , can be trapped by illumination of the S0 ,S 1 and S2 states at cryogenic temperatures. The EPR signals reported were attributed to S0TyrZ % ,S 1TyrZ % and S2TyrZ % , respectively. The equivalent states were examined here by EPR in PSII isolated from Thermosynechococcus elongatus with either Sr or Ca associated with the Mn4 cluster. In order to avoid spectral contributions from the second tyrosyl radical, TyrD % , PSII was used in which Tyr160 of D2 was replaced by phenylalanine. We report that the metalloradical signals attributed to TyrZ % interacting with the Mn cluster in S0 ,S 1 ,S 2 and also probably the S3 states are all affected by the presence of Sr. Ca/Sr exchange also affects the non-haem
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new insights on chld1 function in photosystem ii from site directed mutants of d1 t179 in Thermosynechococcus elongatus
Biochimica et Biophysica Acta, 2019Co-Authors: Yuki Takegawa, Alain Boussac, William A Rutherford, Takumi Noguchi, Makoto Nakamura, Shin Nakamura, Julien Selles, Miwa SugiuraAbstract:The monomeric chlorophyll, Chl(D1), which is located between the PD1PD2 chlorophyll pair and the pheophytin, Pheo(D1), is the longest wavelength chlorophyll in the heart of Photosystem II and is thought to be the primary electron donor. Its central Mg2+ is liganded to a water molecule that is H-bonded to D1/T179. Here, two site-directed mutants, D1/T179H and D1/T179V, were made in the thermophilic cyanobacterium, Thermosynechococcus elongatus, and characterized by a range of biophysical techniques. The Mn4CaO5 cluster in the water-splitting site is fully active in both mutants. Changes in thermoluminescence indicate that i) radiative recombination occurs via the repopulation of *Chl(D1) itself; ii) non-radiative charge recombination reactions appeared to be faster in the T179H-PSII; and iii) the properties of PD1PD2 were unaffected by this mutation, and consequently iv) the immediate precursor state of the radiative excited state is the Chl(D1)(+)Pheo(D1)(-) radical pair. Chlorophyll bleaching due to high intensity illumination correlated with the amount of O-1(2) generated. Comparison of the bleaching spectra with the electrochromic shifts attributed to Chl(D1) upon Q(A)(-) formation, indicates that in the T179H-PSII and in the WT*3-PSII, the Chl(D1) itself is the chlorophyll that is first damaged by O-1(2), whereas in the T179V-PSII a more red chlorophyll is damaged, the identity of which is discussed. Thus, Chl(D1) appears to be one of the primary damage site in recombination-mediated photoinhibition. Finally, changes in the absorption of Chl(D1) very likely contribute to the well-known electrochromic shifts observed at similar to 430 nm during the S-state cycle.
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variants of photosystem ii d1 protein in Thermosynechococcus elongatus
Research on Chemical Intermediates, 2014Co-Authors: Miwa Sugiura, Alain BoussacAbstract:Cyanobacteria have several psbA genes encoding PsbA, the D1 reaction center protein of the photosystem II (PSII) complex which bears, with PsbD, the D2 protein, most of the cofactors involved in electron-transfer reactions. The thermophilic cyanobacterium Thermosynechococcus elongatus has three psbA genes differently expressed depending on the environmental conditions. Among the 344 residues constituting each of the three possible PsbA variants there are 21 substitutions between PsbA1 and PsbA3, 31 between PsbA1 and PsbA2, and 27 between PsbA2 and PsbA3. In this review, we briefly summarize the changes already identified in the properties of the redox cofactors depending on the D1 variant constituting PSII in T. elongatus.
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some photosystem ii properties depending on the d1 protein variants in Thermosynechococcus elongatus
Biochimica et Biophysica Acta, 2014Co-Authors: Miwa Sugiura, Alain BoussacAbstract:Abstract Cyanobacteria have multiple psbA genes encoding PsbA, the D1 reaction center protein of the Photosystem II complex which bears together with PsbD, the D2 protein, most of the cofactors involved in electron transfer reactions. The thermophilic cyanobacterium Thermosynechococcus elongatus has three psbA genes differently expressed depending on the environmental conditions. Among the 344 residues constituting each of the 3 possible PsbA variants there are 21 substitutions between PsbA1 and PsbA3, 31 between PsbA1 and PsbA2 and 27 between PsbA2 and PsbA3. In this review, we summarize the changes already identified in the properties of the redox cofactors depending on the D1 variant constituting Photosystem II in T. elongatus . This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: Keys to Produce Clean Energy.
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modification of the pheophytin redox potential in Thermosynechococcus elongatus photosystem ii with psba3 as d1
Biochimica et Biophysica Acta, 2014Co-Authors: Miwa Sugiura, William A Rutherford, Fabrice Rappaport, Chizuko Azami, Kazumi Koyama, Alain BoussacAbstract:Abstract In Photosystem II (PSII) of the cyanobacterium Thermosynechococcus elongatus, glutamate 130 in the high-light variant of the D1-subunit (PsbA3) was changed to glutamine in a strain lacking the two other genes for D1, psbA1 and psbA2. The resulting PSII (PsbA3/Glu130Gln) was compared with those from the “native” high-light (PsbA3-PSII) and low-light (PsbA1-PSII) variants, which differ by 21 amino acid including Glu130Gln. H-bonding from D1-Glu130Gln to the primary electron acceptor, PheophytinD1 (PheoD1), is known to affect the Em of the PheoD1/PheoD1− couple. The Gln130 mutation here had little effect on water splitting, charge accumulation and photosensitivity but did slow down S2QA− charge recombination and up-shift the thermoluminescence while increasing its yield. These changes were consistent with a ≈ − 30 mV shift of the PheoD1/PheoD1− Em, similar to earlier single site-mutation results from other species and double the ≈ − 17 mV shift seen for PsbA1-PSII versus PsbA3-PSII. This is attributed to the influence of the other 20 amino-acids that differ in PsbA3. A computational model for simulating S2QA− recombination matched the experimental trend: the S2QA− recombination rate in PsbA1-PSII differed only slightly from that in PsbA3-PSII, while in Glu130-PsbA3-PSII there was a more pronounced slowdown of the radical pair decay. The simulation predicted a major effect of the PheoD1/PheoD1− potential on 1O2 yield (~ 60% in PsbA1-PSII, ~ 20% in PsbA3-PSII and ~ 7% in Gln130-PsbA3-PSII), reflecting differential sensitivities to high light.
Athina Zouni - One of the best experts on this subject based on the ideXlab platform.
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The antenna system of photosystem II from Thermosynechococcus elongatus at 3.2 A resolution.
Photosynthesis research, 2020Co-Authors: Bernhard Loll, Jan Kern, Athina Zouni, Wolfram Saenger, Jacek Biesiadka, Klaus-dieter IrrgangAbstract:The content and type of cofactors harboured in the Photosystem II core complex (PS IIcc) of the cyanobacterium Thermosynechococcus elongatus has been determined by biochemical and spectroscopic methods. 17 +/- 1 chlorophyll a per pheophytin a and 0.25 beta-carotene per chlorophyll a have been found in re-dissolved crystals of dimeric PS IIcc. The X-ray crystal structure of PS IIcc from Thermosynechococcus elongatus at 3.2 A resolution clearly shows chlorophyll a molecules arranged in two layers close to the cytoplasmic and lumenal sides of the thylakoid membrane. Each of the cytoplasmic layers contains 9 chlorophyll a, whose positions and orientations are related by a local twofold rotation pseudo-C2 axis passing through the non-haem Fe2+. These chlorophyll a are arranged comparably to those in the antenna domains of PsaA and PsaB of cyanobacterial Photosystem I affirming an evolutionary relation. The chlorophyll a in the lumenal layer are less well conserved between Photosystems I and II and even between CP43 and CP47 with 4 chlorophyll a in the former and 7 in the latter.
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insights into the binding behavior of native and non native cytochromes to photosystem i from Thermosynechococcus elongatus
Journal of Biological Chemistry, 2018Co-Authors: Adrian Kolsch, Jan Kern, Heiko Lokstein, Mahdi Hejazi, Kai Stieger, Sven Christian Feifel, Fred Lisdat, Athina ZouniAbstract:: The binding of photosystem I (PS I) from Thermosynechococcus elongatus to the native cytochrome (cyt) c6 and cyt c from horse heart (cyt cHH) was analyzed by oxygen consumption measurements, isothermal titration calorimetry (ITC), and rigid body docking combined with electrostatic computations of binding energies. Although PS I has a higher affinity for cyt cHH than for cyt c6, the influence of ionic strength and pH on binding is different in the two cases. ITC and theoretical computations revealed the existence of unspecific binding sites for cyt cHH besides one specific binding site close to P700 Binding to PS I was found to be the same for reduced and oxidized cyt cHH Based on this information, suitable conditions for cocrystallization of cyt cHH with PS I were found, resulting in crystals with a PS I:cyt cHH ratio of 1:1. A crystal structure at 3.4-A resolution was obtained, but cyt cHH cannot be identified in the electron density map because of unspecific binding sites and/or high flexibility at the specific binding site. Modeling the binding of cyt c6 to PS I revealed a specific binding site where the distance and orientation of cyt c6 relative to P700 are comparable with cyt c2 from purple bacteria relative to P870 This work provides new insights into the binding modes of different cytochromes to PS I, thus facilitating steps toward solving the PS I-cyt c costructure and a more detailed understanding of natural electron transport processes.
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solution structure of monomeric and trimeric photosystem i of Thermosynechococcus elongatus investigated by small angle x ray scattering
Photosynthesis Research, 2017Co-Authors: Maksym Golub, Athina Zouni, Heiko Lokstein, Adrian Kolsch, Mahdi Hejazi, D Florian C Wieland, Jorg PieperAbstract:The structure of monomeric and trimeric photosystem I (PS I) of Thermosynechococcus elongatus BP1 (T. elongatus) was investigated by small-angle X-ray scattering (SAXS). The scattering data reveal that the protein–detergent complexes possess radii of gyration of 58 and 78 A in the cases of monomeric and trimeric PS I, respectively. The results also show that the samples are monodisperse, virtually free of aggregation, and contain empty detergent micelles. The shape of the protein–detergent complexes can be well approximated by elliptical cylinders with a height of 78 A. Monomeric PS I in buffer solution exhibits minor and major radii of the elliptical cylinder of about 50 and 85 A, respectively. In the case of trimeric PS I, both radii are equal to about 110 A. The latter model can be shown to accommodate three elliptical cylinders equal to those describing monomeric PS I. A structure reconstitution also reveals that the protein–detergent complexes are larger than their respective crystal structures. The reconstituted structures are larger by about 20 A mainly in the region of the hydrophobic surfaces of the monomeric and trimeric PS I complexes. This seeming contradiction can be resolved by the addition of a detergent belt constituted by a monolayer of dodecyl-β-D-maltoside molecules. Assuming a closest possible packing, a number of roughly 1024 and 1472 detergent molecules can be determined for monomeric and trimeric PS I, respectively. Taking the monolayer of detergent molecules into account, the solution structure can be almost perfectly modeled by the crystal structures of monomeric and trimeric PS I.
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spectroscopic properties of photosystem ii core complexes from Thermosynechococcus elongatus revealed by single molecule experiments
Biochimica et Biophysica Acta, 2014Co-Authors: Athina Zouni, Marc Brecht, Alexander Konrad, Sepideh Skandary, Alfred J Meixner, Martin Hussels, Julia Hellmich, Carina GlocknerAbstract:Abstract In this study we use a combination of absorption, fluorescence and low temperature single-molecule spectroscopy to elucidate the spectral properties, heterogeneities and dynamics of the chlorophyll a (Chl a ) molecules responsible for the fluorescence emission of photosystem II core complexes (PS II cc) from the cyanobacterium Thermosynechococcus elongatus . At the ensemble level, the absorption and fluorescence spectra show a temperature dependence similar to plant PS II. We report emission spectra of single PS II cc for the first time; the spectra are dominated by zero-phonon lines (ZPLs) in the range between 680 and 705 nm. The single-molecule experiments show unambiguously that different emitters and not only the lowest energy trap contribute to the low temperature emission spectrum. The average emission spectrum obtained from more than hundred single complexes shows three main contributions that are in good agreement with the reported bands F685, F689 and F695. The intensity of F695 is found to be lower than in conventional ensemble spectroscopy. The reason for the deviation might be due to the accumulation of triplet states on the red-most chlorophylls (e.g. Chl29 in CP47) or on carotenoids close to these long-wavelength traps by the high excitation power used in the single-molecule experiments. The red-most emitter will not contribute to the fluorescence spectrum as long as it is in the triplet state. In addition, quenching of fluorescence by the triplet state may lead to a decrease of long-wavelength emission.
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crystal structure of monomeric photosystem ii from Thermosynechococcus elongatus at 3 6 a resolution
Journal of Biological Chemistry, 2010Co-Authors: Matthias Broser, Jan Kern, Wolfram Saenger, A G Gabdulkhakov, Albert Guskov, Athina ZouniAbstract:Abstract The membrane-embedded photosystem II core complex (PSIIcc) uses light energy to oxidize water in photosynthesis. Information about the spatial structure of PSIIcc obtained from x-ray crystallography was so far derived from homodimeric PSIIcc of thermophilic cyanobacteria. Here, we report the first crystallization and structural analysis of the monomeric form of PSIIcc with high oxygen evolution capacity, isolated from Thermosynechococcus elongatus. The crystals belong to the space group C2221, contain one monomer per asymmetric unit, and diffract to a resolution of 3.6 A. The x-ray diffraction pattern of the PSIIcc-monomer crystals exhibit less anisotropy (dependence of resolution on crystal orientation) compared with crystals of dimeric PSIIcc, and the packing of the molecules within the unit cell is different. In the monomer, 19 protein subunits, 35 chlorophylls, two pheophytins, the non-heme iron, the primary plastoquinone QA, two heme groups, 11 β-carotenes, 22 lipids, seven detergent molecules, and the Mn4Ca cluster of the water oxidizing complex could be assigned analogous to the dimer. Based on the new structural information, the roles of lipids and protein subunits in dimer formation of PSIIcc are discussed. Due to the lack of non-crystallographic symmetry and the orientation of the membrane normal of PSIIcc perpendicular (∼87°) to the crystallographic b-axis, further information about the structure of the Mn4Ca cluster is expected to become available from orientation-dependent spectroscopy on this new crystal form.
Masako Iwai - One of the best experts on this subject based on the ideXlab platform.
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Functional Analysis of PsbZ in Photosystem II from the Thermophilic Cyanobacterium Thermosynechococcus elongatus BP-1
Photosynthesis. Energy from the Sun, 2020Co-Authors: Masako Iwai, Takehiro Suzuki, Naoshi Dohmae, Yasunori InoueAbstract:PsbZ is a membrane protein of 6.5 kDa found in photosystem II (PSII) complexes from cyanobacteria to land plants. The two helices of PsbZ are located on the perimeter of the dimer near CP43 and PsbK in the cyanobacterial PSII structure. In tobacco and Chlamydomonas reinhardtii, psbZ knockout leads to reduce amounts of the minor antenna protein CP26. However, CP26 is not found in the cyanobacterial thylakoids. The function of PsbZ in cyanobacteria is still not clear. In this work, we deleted psbZ gene in the thermophilic cyanobacterium, Thermosynechococcus elongatus BP-1 to analyze the function of PsbZ. No difference was observed in the growth under various light conditions, and in the oxygen-evolving activities between the wild type and the mutant. However, the oxygen-evolving activity in the mutant PSII complexes purified by Ni-affinity chromatography was lower than those in the purified wild-type PSII complexes. Electrophoretic profile of the mutant PSII complexes revealed that most of PsbK band had disappeared but no significant release of the extrinsic proteins was observed. N-terminal amino acid sequences of PsbK and PsbM/Ycf12 bands showed that most of Ycf12 as well as PsbK was lost in the mutant PSII complexes. These indicate that PsbZ is required for the stable binding of PsbK and Ycf12 to the PSII core. We suggest that Ycf12 is the unidentified X1 polypeptide (Loll et al. 2005) that is observed near PsbZ and PsbK in the crystal structure of the PSII complex.
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functional characterization and quantification of the alternative psba copies in Thermosynechococcus elongatus and their role in photoprotection
Journal of Biological Chemistry, 2010Co-Authors: Marc M Nowaczyk, Zsuzsanna Deak, Imre Vass, Masako Iwai, Julia Sander, Joachim Buchta, Marta Dorogi, Matthias RognerAbstract:The D1 protein (PsbA) of photosystem II (PSII) from Thermosynechococcus elongatus is encoded by a psbA gene family that is typical of cyanobacteria. Although the transcription of these three genes has been studied previously (Kos, P. B., Deak, Z., Cheregi, O., and Vass, I. (2008) Biochim. Biophys. Acta 1777, 74–83), the protein quantification had not been possible due to the high sequence identity between the three PsbA copies. The successful establishment of a method to quantify the PsbA proteins on the basis of reverse phase-LC-electrospray mass ionization-MS/MS (RP-LC-ESI-MS/MS) enables an accurate comparison of transcript and protein level for the first time ever. Upon high light incubation, about 70% PsbA3 could be detected, which closely corresponds to the transcript level. It was impossible to detect any PsbA2 under all tested conditions. The construction of knock-out mutants enabled for the first time a detailed characterization of both whole cells and also isolated PSII complexes. PSII complexes of the ΔpsbA1/psbA2 mutant contained only copy PsbA3, whereas only PsbA1 could be detected in PSII complexes from the ΔpsbA3 mutant. In whole cells as well as in isolated complexes, a shift of the free energy between the redox pairs in the PsbA3 complexes in comparison with PsbA1 could be detected by thermoluminescence and delayed fluorescence measurements. This change is assigned to a shift of the redox potential of pheophytin toward more positive values. Coincidentally, no differences in the QA-QB electron transfer could be observed in flash-induced fluorescence decay or prompt fluorescence measurements. In conclusion, PsbA3 complexes yield a better protection against photoinhibition due to a higher probability of the harmless dissipation of excess energy.
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the psbk subunit is required for the stable assembly and stability of other small subunits in the psii complex in the thermophilic cyanobacterium Thermosynechococcus elongatus bp 1
Plant and Cell Physiology, 2010Co-Authors: Masako Iwai, Takehiro Suzuki, Naoshi Dohmae, Yasunori Inoue, Akiko Kamiyama, Isamu Sakurai, Masahiko IkeuchiAbstract:: PsbK is a small membrane protein of the PSII core complex and is highly conserved from cyanobacteria to plants. Here, we studied its role in the thermophilic cyanobacterium, Thermosynechococcus elongatus BP-1, by focusing on a psbK disruptant with hexahistidine-tagged CP47. The psbK disruptant showed photoautotrophic growth comparable with that of the wild type under a wide range of light conditions. The mutant PSII complex retained the oxygen-evolving activity with a unique modification of the acceptor Q(B) site. N-terminal sequencing revealed that Ycf12 and PsbZ proteins were lost in the PSII complex prepared from the mutant. Immunoblotting detected reduced accumulation of PsbZ in the mutant thylakoid. These results suggest that PsbK is required not only for association of PsbZ and Ycf12 with the isolated PSII complex but also for the stabilization of PsbZ in the thylakoid membrane.
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absence of the psbz subunit prevents association of psbk and ycf12 with the psii complex in the thermophilic cyanobacterium Thermosynechococcus elongatus bp 1
Plant and Cell Physiology, 2007Co-Authors: Masako Iwai, Takehiro Suzuki, Naoshi Dohmae, Yasunori Inoue, Masahiko IkeuchiAbstract:PsbZ (Ycf9) is a membrane protein of PSII complexes and is highly conserved from cyanobacteria to plants. We deleted the psbZ gene in the thermophilic cyanobacterium, Thermosynechococcus elongatus. The mutant cells showed photoautotrophic growth indistinguishable from that of the wild type under low and standard light conditions, while they showed even better growth than the wild type under high light. The mutant accumulated less carotenoids and more phycobiliproteins than the wild type under high light, suggestive of tolerance to photoinhibition. The mutant cells evolved oxygen at a rate comparable with the wild type, while the PSII complex isolated from the mutant retained much lower activity than the wild type. N-terminal sequencing revealed that Ycf12 and PsbK proteins were almost lost in the PSII complex. These results indicate that PsbZ is involved in functional integrity of the PSII complex by stabilizing PsbK and Ycf12. We suggest that Ycf12 is an unidentified membrane-spanning polypeptide that is placed near PsbZ and PsbK in the crystal structure of PSII.
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isolation subunit composition and interaction of the ndh 1 complexes from Thermosynechococcus elongatus bp 1
Biochemical Journal, 2005Co-Authors: Pengpeng Zhang, Masahiko Ikeuchi, Masako Iwai, Natalia Battchikova, Teruo Ogawa, Virpi Paakkarinen, Hirokazu Katoh, Himadri B PakrasiAbstract:NDH (NADH-quinone oxidoreductase)-1 complexes in cyanobacteria have specific functions in respiration and cyclic electron flow as well as in active CO2 uptake. In order to isolate NDH-1 complexes and to study complex–complex interactions, several strains of Thermosynechococcus elongatus were constructed by adding a His-tag (histidine tag) to different subunits of NDH-1. Two strains with His-tag on CupA and NdhL were successfully used to isolate NDH-1 complexes by one-step Ni2+ column chromatography. BN (blue-native)/SDS/PAGE analysis of the proteins eluted from the Ni2+ column revealed the presence of three complexes with molecular masses of about 450, 300 and 190 kDa, which were identified by MS to be NDH-1L, NDH-1M and NDH-1S respectively, previously found in Synechocystis sp. PCC 6803. A larger complex of about 490 kDa was also isolated from the NdhL-His strain. This complex, designated ‘NDH-1MS’, was composed of NDH-1M and NDH-1S. NDH-1L complex was recovered from WT (wild-type) cells of T. elongatus by Ni2+ column chromatography. NdhF1 subunit present only in NDH-1L has a sequence of -HHDHHSHH- internally, which appears to have an affinity for the Ni2+ column. NDH-1S or NDH-1M was not recovered from WT cells by chromatography of this kind. The BN/SDS/PAGE analysis of membranes solubilized by a low concentration of detergent indicated the presence of abundant NDH-1MS, but not NDH-1M or NDH-1S. These results clearly demonstrated that NDH-1S is associated with NDH-1M in vivo.
