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Niklas J, Agostini A, Carbonera D, Di Valentin M, Lubitz W. Primary donor triplet states of Photosystem I and II studied by Q-band pulse ENDOR spectroscopy. PHOTOSYNTHESIS RESEARCH 2022; 152:213-234. [PMID: 35290567 PMCID: PMC9424170 DOI: 10.1007/s11120-022-00905-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/14/2022] [Indexed: 05/05/2023]
Abstract
The photoexcited triplet state of the "primary donors" in the two photosystems of oxygenic photosynthesis has been investigated by means of electron-nuclear double resonance (ENDOR) at Q-band (34 GHz). The data obtained represent the first set of 1H hyperfine coupling tensors of the 3P700 triplet state in PSI and expand the existing data set for 3P680. We achieved an extensive assignment of the observed electron-nuclear hyperfine coupling constants (hfcs) corresponding to the methine α-protons and the methyl group β-protons of the chlorophyll (Chl) macrocycle. The data clearly confirm that in both photosystems the primary donor triplet is located on one specific monomeric Chl at cryogenic temperature. In comparison to previous transient ENDOR and pulse ENDOR experiments at standard X-band (9-10 GHz), the pulse Q-band ENDOR spectra demonstrate both improved signal-to-noise ratio and increased resolution. The observed ENDOR spectra for 3P700 and 3P680 differ in terms of the intensity loss of lines from specific methyl group protons, which is explained by hindered methyl group rotation produced by binding site effects. Contact analysis of the methyl groups in the PSI crystal structure in combination with the ENDOR analysis of 3P700 suggests that the triplet is located on the Chl a' (PA) in PSI. The results also provide additional evidence for the localization of 3P680 on the accessory ChlD1 in PSII.
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Affiliation(s)
- Jens Niklas
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany.
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave., Lemont, IL, 60439, USA.
| | - Alessandro Agostini
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy
- Biology Centre, Institute of Plant Molecular Biology, Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Marilena Di Valentin
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy.
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany.
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2
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Kurashov V, Gorka M, Milanovsky GE, Johnson TW, Cherepanov DA, Semenov AY, Golbeck JH. Critical evaluation of electron transfer kinetics in P700–FA/FB, P700–FX, and P700–A1 Photosystem I core complexes in liquid and in trehalose glass. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1288-1301. [DOI: 10.1016/j.bbabio.2018.09.367] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 09/15/2018] [Accepted: 09/17/2018] [Indexed: 12/12/2022]
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3
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Jana S, Du T, Nagao R, Noguchi T, Shibata Y. Redox-state dependent blinking of single photosystem I trimers at around liquid-nitrogen temperature. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:30-40. [PMID: 30428304 DOI: 10.1016/j.bbabio.2018.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 08/21/2018] [Accepted: 11/04/2018] [Indexed: 10/27/2022]
Abstract
Efficient light harvesting in a photosynthetic antenna system is disturbed by a ragged and fluctuating energy landscape of the antenna pigments in response to the conformation dynamics of the protein. This situation is especially pronounced in Photosystem I (PSI) containing red shifted chlorophylls (red Chls) with the excitation energy much lower than the primary donor. The present study was conducted to clarify light-harvesting dynamics of PSI isolated from Synechocystis sp. PCC6803 by using single-molecule spectroscopy at liquid‑nitrogen temperatures. Fluorescence emission at around 720 nm from the red Chls in single PSI trimers was monitored at 80-100 K. Intermittent variations in the emission intensities, so-called blinking, were frequently observed. Its time scale lay in several tens of seconds. The blinking amplitude depended on the redox state of the phylloquinone (A1). Electrochromic shifts of Chls induced by the negative charge on A1 were calculated based on the X-ray crystallographic structure. A Chl molecule, Chl-A839 (numbering according to PDB 5OY0), bound near A1 was found to have a large electrochromic shift. This Chl has strong exciton coupling with neighboring Chl (A838) whose site energy was predicted to be determined by interaction with an arginine residue (ArgF84) [Adolphs et al., 2010]. A possible scenario of the blinking was proposed. Conformational fluctuations of ArgF84 seesaw the excitation-energy of Chl-A838, which perturbs the branching ratio of excitation-energy between the red Chl and the cationic form of P700 as a quencher. The electrochromic shift of Chl-A839 enhances the effect of the conformation dynamics of ArgF84.
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Affiliation(s)
- Sankar Jana
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Ting Du
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Ryo Nagao
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yutaka Shibata
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578, Japan.
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4
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Makita H, Hastings G. Photosystem I with benzoquinone analogues incorporated into the A 1 binding site. PHOTOSYNTHESIS RESEARCH 2018; 137:85-93. [PMID: 29332243 DOI: 10.1007/s11120-018-0480-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/02/2018] [Indexed: 06/07/2023]
Abstract
Time-resolved FTIR difference spectroscopy has been used to study photosystem I (PSI) particles with three different benzoquinones [plastoquinone-9 (PQ), 2,6-dimethyl-1,4-benzoquinone (DMBQ), 2,3,5,6-tetrachloro-1,4-benzoquinone (Cl4BQ)] incorporated into the A1 binding site. If PSI samples are cooled in the dark to 77 K, the incorporated benzoquinones are shown to be functional, allowing the production of time-resolved (P700+A1--P700A1) FTIR difference spectra. If samples are subjected to repetitive flash illumination at room temperature prior to cooling, however, the time-resolved FTIR difference spectra at 77 K display contributions typical of the P700 triplet state (3P700), indicating a loss of functionality of the incorporated benzoquinones, that occurs because of double protonation of the incorporated benzoquinones. The benzoquinone protonation mechanism likely involves nearby water molecules but does not involve the terminal iron-sulfur clusters FA and FB. These results and conclusions resolve discrepancies between results from previous low-temperature FTIR and EPR studies on similar PSI samples with PQ incorporated.
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Affiliation(s)
- Hiroki Makita
- Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 605, Atlanta, GA, 30303, USA
| | - Gary Hastings
- Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 605, Atlanta, GA, 30303, USA.
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5
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Shelaev IV, Mamedov MD, Gostev FE, Aybush AV, Li M, Nguyen J, Bruce BD, Nadtochenko VA. Comparisons of Electron Transfer Reactions in a Cyanobacterial Tetrameric and Trimeric Photosystem I Complexes. Photochem Photobiol 2018; 94:564-569. [DOI: 10.1111/php.12886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/05/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Ivan V. Shelaev
- N.N. Semenov Institute of Chemical Physics Russian Academy of Sciences Moscow Russia
| | - Mahir D. Mamedov
- A.N. Belozersky Institute of Physical–Chemical Biology Moscow State University Moscow Russia
| | - Fedor E. Gostev
- N.N. Semenov Institute of Chemical Physics Russian Academy of Sciences Moscow Russia
| | - Arseny V. Aybush
- N.N. Semenov Institute of Chemical Physics Russian Academy of Sciences Moscow Russia
| | - Meng Li
- Department of Biochemistry and Cellular and Molecular Biology University of Tennessee Knoxville TN
- Bredesen Center for Interdisciplinary Research University of Tennessee Knoxville TN
| | - Jonathan Nguyen
- Department of Biochemistry and Cellular and Molecular Biology University of Tennessee Knoxville TN
| | - Barry D. Bruce
- Department of Biochemistry and Cellular and Molecular Biology University of Tennessee Knoxville TN
- Bredesen Center for Interdisciplinary Research University of Tennessee Knoxville TN
- Department of Microbiology University of Tennessee Knoxville TN
| | - Victor A. Nadtochenko
- N.N. Semenov Institute of Chemical Physics Russian Academy of Sciences Moscow Russia
- Moscow Institute of Physics and Technology Dolgoprudny Russia
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6
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Shelaev I, Gorka M, Savitsky A, Kurashov V, Mamedov M, Gostev F, Möbius K, Nadtochenko V, Golbeck J, Semenov A. Effect of Dehydrated Trehalose Matrix on the Kinetics of Forward Electron Transfer Reactions in Photosystem I. ACTA ACUST UNITED AC 2016. [DOI: 10.1515/zpch-2016-0860] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
The effect of dehydration on the kinetics of forward electron transfer (ET) has been studied in cyanobacterial photosystem I (PS I) complexes in a trehalose glassy matrix by time-resolved optical and EPR spectroscopies in the 100 fs to 1 ms time domain. The kinetics of the flash-induced absorption changes in the subnanosecond time domain due to primary and secondary charge separation steps were monitored by pump–probe laser spectroscopy with 20-fs low-energy pump pulses centered at 720 nm. The back-reaction kinetics of P700 were measured by high-field time-resolved EPR spectroscopy and the forward kinetics of
A
1A
•
−
/
A
1
B
•
−
→
F
X
${\rm{A}}_{{\rm{1A}}}^{ \bullet - }/{\rm{A}}_{1{\rm{B}}}^{ \bullet - } \to {{\rm{F}}_{\rm{X}}}$
by time-resolved optical spectroscopy at 480 nm. The kinetics of the primary ET reactions to form the primary
P
700
•
+
A
0
•
−
${\rm{P}}_{700}^{ \bullet + }{\rm{A}}_0^{ \bullet - }$
and the secondary
P
700
•
+
A
1
•
−
${\rm{P}}_{700}^{ \bullet + }{\rm{A}}_1^{ \bullet - }$
ion radical pairs were not affected by dehydration in the trehalose matrix, while the yield of the
P
700
•
+
A
1
•
−
${\rm{P}}_{700}^{ \bullet + }{\rm{A}}_1^{ \bullet - }$
was decreased by ~20%. Forward ET from the phylloquinone molecules in the
A
1
A
•
−
${\rm{A}}_{1{\rm{A}}}^{ \bullet - }$
and
A
1
B
•
−
${\rm{A}}_{1{\rm{B}}}^{ \bullet - }$
sites to the iron–sulfur cluster FX slowed from ~220 ns and ~20 ns in solution to ~13 μs and ~80 ns, respectively. However, as shown by EPR spectroscopy, the ~15 μs kinetic phase also contains a small contribution from the recombination between
A
1
B
•
−
${\rm{A}}_{1{\rm{B}}}^{ \bullet - }$
and
P
700
•
+
.
${\rm{P}}_{700}^{ \bullet + }.$
These data reveal that the initial ET reactions from P700 to secondary phylloquinone acceptors in the A- and B-branches of cofactors (A1A and A1B) remain unaffected whereas ET beyond A1A and A1B is slowed or prevented by constrained protein dynamics due to the dry trehalose glass matrix.
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Affiliation(s)
- Ivan Shelaev
- N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, 119991 Moscow, Russian Federation
| | - Michael Gorka
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States of America
| | - Anton Savitsky
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany , Phone: 0049-208-3063555, Fax: 0049-208-3063955
| | - Vasily Kurashov
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States of America
| | - Mahir Mamedov
- A.N. Belozersky Institute of Physical–Chemical Biology, Moscow State University, Moscow, Leninskie Gory, Moscow 119992, Russian Federation
| | - Fedor Gostev
- N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, 119991 Moscow, Russian Federation
| | - Klaus Möbius
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Victor Nadtochenko
- N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, 119991 Moscow, Russian Federation
| | - John Golbeck
- Department of Biochemistry and Molecular Biology, Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States of America
| | - Alexey Semenov
- N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, 119991 Moscow, Russian Federation
- A.N. Belozersky Institute of Physical–Chemical Biology, Moscow State University, Moscow, Leninskie Gory, Moscow 119992, Russian Federation
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7
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Makita H, Hastings G. Modeling electron transfer in photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:723-33. [DOI: 10.1016/j.bbabio.2016.03.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/13/2016] [Accepted: 03/15/2016] [Indexed: 11/26/2022]
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8
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Mamedov M, Nadtochenko V, Semenov A. Primary electron transfer processes in photosynthetic reaction centers from oxygenic organisms. PHOTOSYNTHESIS RESEARCH 2015; 125:51-63. [PMID: 25648636 DOI: 10.1007/s11120-015-0088-y] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/12/2015] [Indexed: 05/22/2023]
Abstract
This minireview is written in honor of Vladimir A. Shuvalov, a pioneer in the area of primary photochemistry of both oxygenic and anoxygenic photosyntheses (See a News Report: Allakhverdiev et al. 2014). In the present paper, we describe the current state of the formation of the primary and secondary ion-radical pairs within photosystems (PS) II and I in oxygenic organisms. Spectral-kinetic studies of primary events in PS II and PS I, upon excitation by ~20 fs laser pulses, are now available and reviewed here; for PS II, excitation was centered at 710 nm, and for PS I, it was at 720 nm. In PS I, conditions were chosen to maximally increase the relative contribution of the direct excitation of the reaction center (RC) in order to separate the kinetics of the primary steps of charge separation in the RC from that of the excitation energy transfer in the antenna. Our results suggest that the sequence of the primary electron transfer reactions is P680 → ChlD1 → PheD1 → QA (PS II) and P700 → A 0A/A 0B → A 1A/A 1B (PS I). However, alternate routes of charge separation in PS II, under different excitation conditions, are not ruled out.
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Affiliation(s)
- Mahir Mamedov
- A.N. Belozersky Institute of Physical-Chemical Biology, Moscow State University, 119991, Moscow, Russia,
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9
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Semenov AY, Petrova AA, Mamedov MD, Nadtochenko VA. Electron transfer in photosystem I containing native and modified quinone acceptors. BIOCHEMISTRY (MOSCOW) 2015; 80:654-61. [DOI: 10.1134/s0006297915060024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Milanovsky GE, Ptushenko VV, Cherepanov DA, Semenov AY. Mechanism of primary and secondary ion-radical pair formation in photosystem I complexes. BIOCHEMISTRY (MOSCOW) 2014; 79:221-6. [PMID: 24821448 DOI: 10.1134/s0006297914030079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The mechanisms of the ultrafast charge separation in reaction centers of photosystem I (PS I) complexes are discussed. A kinetic model of the primary reactions in PS I complexes is presented. The model takes into account previously calculated values of redox potentials of cofactors, reorganization energies of the primary P700(+)A0(-) and secondary P700(+)A1(-) ion-radical pairs formation, and the possibility of electron transfer via both symmetric branches A and B of redox-cofactors. The model assumes that the primary electron acceptor A0 in PS I is represented by a dimer of chlorophyll molecules Chl2A/Chl3A and Chl2B/Chl3B in branches A and B of the cofactors. The characteristic times of formation of P700(+)A0(-) and P700(+)A1(-) calculated on the basis of the model are close to the experimental values obtained by pump-probe femtosecond absorption spectroscopy. It is demonstrated that a small difference in the values of redox potentials between the primary electron acceptors A0A and A0B in branches A and B leads to asymmetry of the electron transfer in a ratio of 70 : 30 in favor of branch A. The secondary charge separation is thermodynamically irreversible in the submicrosecond range and is accompanied by additional increase in asymmetry between the branches of cofactors of PS I.
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Affiliation(s)
- G E Milanovsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
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11
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Evidence that histidine forms a coordination bond to the A0A and A0B chlorophylls and a second H-bond to the A1A and A1B phylloquinones in M688HPsaA and M668HPsaB variants of Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1362-75. [DOI: 10.1016/j.bbabio.2014.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 04/02/2014] [Accepted: 04/04/2014] [Indexed: 11/21/2022]
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12
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Shibata Y, Katoh W, Chiba T, Namie K, Ohnishi N, Minagawa J, Nakanishi H, Noguchi T, Fukumura H. Development of a novel cryogenic microscope with numerical aperture of 0.9 and its application to photosynthesis research. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:880-7. [PMID: 24650629 DOI: 10.1016/j.bbabio.2014.03.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 03/05/2014] [Accepted: 03/10/2014] [Indexed: 01/15/2023]
Abstract
A novel cryogenic optical-microscope system was developed in which the objective lens is set inside of the cryostat adiabatic vacuum space. Being isolated from the sample when it was cooled, the objective lens was maintained at room temperature during the cryogenic measurement. Therefore, the authors were able to use a color-aberration corrected objective lens with a numerical aperture of 0.9. The lens is equipped with an air vent for compatibility to the vacuum. The theoretically expected spatial resolutions of 0.39μm along the lateral direction and 1.3μm along the axial direction were achieved by the developed system. The system was applied to the observations of non-uniform distributions of the photosystems in the cells of a green alga, Chlamydomonas reinhardtii, at 94K. Gaussian decomposition analysis of the fluorescence spectra at all the pixels clearly demonstrated a non-uniform distribution of the two photosystems, as reflected in the variable ratios of the fluorescence intensities assigned to photosystem II and to those assigned to photosystem I. The system was also applied to the fluorescence spectroscopy of single isolated photosystem I complexes at 90K. The fluorescence, assigned to be emitted from a single photosystem I trimer, showed an intermittent fluctuation called blinking, which is typical for a fluorescence signal from a single molecule. The vibronic fluorescence bands at around 790nm were observed for single photosystem I trimers, suggesting that the color aberration is not serious up to the 800nm spectral region.
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Affiliation(s)
- Yutaka Shibata
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki aza Aoba, Aoba-ku, Sendai 980-8578, Japan.
| | - Wataru Katoh
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Tomofumi Chiba
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki aza Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Keisuke Namie
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki aza Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Norikazu Ohnishi
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Jun Minagawa
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Hanayo Nakanishi
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Takumi Noguchi
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Hiroshi Fukumura
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki aza Aoba, Aoba-ku, Sendai 980-8578, Japan
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13
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McConnell MD, Cowgill JB, Baker PL, Rappaport F, Redding KE. Double reduction of plastoquinone to plastoquinol in photosystem 1. Biochemistry 2011; 50:11034-46. [PMID: 22103567 DOI: 10.1021/bi201131r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In Photosystem 1 (PS1), phylloquinone (PhQ) acts as a secondary electron acceptor from chlorophyll ec(3) and also as an electron donor to the iron-sulfur cluster F(X). PS1 possesses two virtually equivalent branches of electron transfer (ET) cofactors from P(700) to F(X), and the lifetime of the semiquinone intermediate displays biphasic kinetics, reflecting ET along the two different branches. PhQ in PS1 serves only as an intermediate in ET and is not normally fully reduced to the quinol form. This is in contrast to PS2, in which plastoquinone (PQ) is doubly reduced to plastoquinol (PQH(2)) as the terminal electron acceptor. We purified PS1 particles from the menD1 mutant of Chlamydomonas reinhardtii that cannot synthesize PhQ, resulting in replacement of PhQ by PQ in the quinone-binding pocket. The magnitude of the stable flash-induced P(700)(+) signal of menD1 PS1, but not wild-type PS1, decreased during a train of laser flashes, as it was replaced by a ~30 ns back-reaction from the preceding radical pair (P(700)(+)A(0)(-)). We show that this process of photoinactivation is due to double reduction of PQ in the menD1 PS1 and have characterized the process. It is accelerated at lower pH, consistent with a rate-limiting protonation step. Moreover, a point mutation (PsaA-L722T) in the PhQ(A) site that accelerates ET to F(X) ~2-fold, likely by weakening the sole H-bond to PhQ(A), also accelerates the photoinactivation process. The addition of exogenous PhQ can restore activity to photoinactivated PS1 and confer resistance to further photoinactivation. This process also occurs with PS1 purified from the menB PhQ biosynthesis mutant of Synechocystis PCC 6803, demonstrating that it is a general phenomenon in both prokaryotic and eukaryotic PS1.
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Affiliation(s)
- Michael D McConnell
- Department of Chemistry and Biochemistry and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, United States.
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14
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Srinivasan N, Santabarbara S, Rappaport F, Carbonera D, Redding K, van der Est A, Golbeck JH. Alteration of the H-Bond to the A1A Phylloquinone in Photosystem I: Influence on the Kinetics and Energetics of Electron Transfer. J Phys Chem B 2011; 115:1751-9. [DOI: 10.1021/jp109531b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
| | - Stefano Santabarbara
- Institut de Biologie Physico-Chimique, UMR 7141 CNRS/UPMC, 13 Rue Pierre et Marie Curie, 75005 Paris, France
| | - Fabrice Rappaport
- Institut de Biologie Physico-Chimique, UMR 7141 CNRS/UPMC, 13 Rue Pierre et Marie Curie, 75005 Paris, France
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padua, Via Marzolo 1, 35131 Padova, Italy
| | - Kevin Redding
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Art van der Est
- Department of Chemistry, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario L2S 3A1, Canada
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15
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Yamagishi A, Ikeda Y, Komura M, Koike H, Satoh K, Itoh S, Shibata Y. Shallow Sink in an Antenna Pigment System of Photosystem I of a Marine Centric Diatom, Chaetoceros gracilis, Revealed by Ultrafast Fluorescence Spectroscopy at 17 K. J Phys Chem B 2010; 114:9031-8. [DOI: 10.1021/jp102205v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Atsushi Yamagishi
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Yohei Ikeda
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Masayuki Komura
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Hiroyuki Koike
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Kazuhiko Satoh
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Shigeru Itoh
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Yutaka Shibata
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
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16
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Shibata Y, Yamagishi A, Kawamoto S, Noji T, Itoh S. Kinetically Distinct Three Red Chlorophylls in Photosystem I of Thermosynechococcus elongatus Revealed by Femtosecond Time-Resolved Fluorescence Spectroscopy at 15 K. J Phys Chem B 2010; 114:2954-63. [DOI: 10.1021/jp909583r] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yutaka Shibata
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furo-cho, Nagoya 464-8602, Japan
| | - Atsushi Yamagishi
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furo-cho, Nagoya 464-8602, Japan
| | - Shunsuke Kawamoto
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furo-cho, Nagoya 464-8602, Japan
| | - Tomoyasu Noji
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furo-cho, Nagoya 464-8602, Japan
| | - Shigeru Itoh
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furo-cho, Nagoya 464-8602, Japan
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17
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Srinivasan N, Golbeck JH. Protein–cofactor interactions in bioenergetic complexes: The role of the A1A and A1B phylloquinones in Photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1057-88. [DOI: 10.1016/j.bbabio.2009.04.010] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 04/14/2009] [Accepted: 04/22/2009] [Indexed: 10/20/2022]
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18
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Niklas J, Epel B, Antonkine ML, Sinnecker S, Pandelia ME, Lubitz W. Electronic Structure of the Quinone Radical Anion A1•− of Photosystem I Investigated by Advanced Pulse EPR and ENDOR Techniques. J Phys Chem B 2009; 113:10367-79. [DOI: 10.1021/jp901890z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jens Niklas
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470 Mülheim/Ruhr, Germany, and Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Boris Epel
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470 Mülheim/Ruhr, Germany, and Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Mikhail L. Antonkine
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470 Mülheim/Ruhr, Germany, and Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Sebastian Sinnecker
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470 Mülheim/Ruhr, Germany, and Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Maria-Eirini Pandelia
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470 Mülheim/Ruhr, Germany, and Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Wolfgang Lubitz
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470 Mülheim/Ruhr, Germany, and Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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19
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Gong XM, Hochman Y, Lev T, Bunker G, Carmeli C. The structure of genetically modified iron-sulfur cluster F(x) in photosystem I as determined by X-ray absorption spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1787:97-104. [PMID: 19081389 DOI: 10.1016/j.bbabio.2008.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2008] [Revised: 11/05/2008] [Accepted: 11/11/2008] [Indexed: 11/28/2022]
Abstract
Photosystem I (PS I) mediates light-induced electron transfer from P700 through a chlorophyll a, a quinone and a [4Fe-4S] iron-sulfur cluster F(X), located on the core subunits PsaA/B to iron-sulfur clusters F(A/B) on subunit PsaC. Structure function relations in the native and in the mutant (psaB-C565S/D566E) of the cysteine ligand of F(X) cluster were studied by X-ray absorption spectroscopy (EXAFS) and transient spectroscopy. The structure of F(X) was determined in PS I lacking clusters F(A/B) by interruption of the psaC2 gene of PS I in the cyanobacterium Synechocystis sp PCC 6803. PsaC-deficient mutant cells assembled the core subunits of PS I which mediated electron transfer mostly to the phylloquinone. EXAFS analysis of the iron resolved a [4Fe-4S] cluster in the native PsaC-deficient PS I. Each iron had 4 sulfur and 3 iron atoms in the first and second shells with average Fe-S and Fe-Fe distances of 2.27 A and 2.69 A, respectively. In the C565S/D566E serine mutant, one of the irons of the cluster was ligated to three oxygen atoms with Fe-O distance of 1.81 A. The possibility that the structural changes induced an increase in the reorganization energy that consequently decreased the rate of electron transfer from the phylloquinone to F(X) is discussed.
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Affiliation(s)
- Xiao-Min Gong
- Department of Biochemistry, Tel Aviv University, Tel Aviv 69978, Israel
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20
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Gong XM, Agalarov R, Brettel K, Carmeli C. Control of electron transport in photosystem I by the iron-sulfur cluster FX in response to intra- and intersubunit interactions. J Biol Chem 2003; 278:19141-50. [PMID: 12626505 DOI: 10.1074/jbc.m301808200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Photosystem I (PS I) is a transmembranal multisubunit complex that mediates light-induced electron transfer from plactocyanine to ferredoxin. The electron transfer proceeds from an excited chlorophyll a dimer (P700) through a chlorophyll a (A0), a phylloquinone (A1), and a [4Fe-4S] iron-sulfur cluster FX, all located on the core subunits PsaA and PsaB, to iron-sulfur clusters FA and FB, located on subunit PsaC. Earlier, it was attempted to determine the function of FX in the absence of FA/B mainly by chemical dissociation of subunit PsaC. However, not all PsaC subunits could be removed from the PS I preparations by this procedure without partially damaging FX. We therefore removed subunit PsaC by interruption of the psaC2 gene of PS I in the cyanobacterium Synechocystis sp. PCC 6803. Cells could not grow under photosynthetic conditions when subunit PsaC was deleted, yet the PsaC-deficient mutant cells grew under heterotrophic conditions and assembled the core subunits of PS I in which light-induced electron transfer from P700 to A1 occurred. The photoreduction of FX was largely inhibited, as seen from direct measurement of the extent of electron transfer from A1 to FX. From the crystal structure it can be seen that the removal of subunits PsaC, PsaD, and PsaE in the PsaC-deficient mutant resulted in the braking of salt bridges between these subunits and PsaB and PsaA and the formation of a net of two negative surface charges on PsaA/B. The potential induced on FX by these surface charges is proposed to inhibit electron transport from the quinone. In the complete PS I complex, replacement of a cysteine ligand of FX by serine in site-directed mutation C565S/D566E in subunit PsaB caused an approximately 10-fold slow down of electron transfer from the quinone to FX without much affecting the extent of this electron transfer compared with wild type. Based on these and other results, we propose that FX might have a major role in controlling electron transfer through PS I.
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Affiliation(s)
- Xiao-Min Gong
- Department of Biochemistry, Tel Aviv University, Tel Aviv 69978, Israel
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21
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Zeng MT, Gong XM, Evans MCW, Nelson N, Carmeli C. Stabilization of iron-sulfur cluster F(X) by intra-subunit interactions unraveled by suppressor and second site-directed mutations in PsaB of Photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1556:254-64. [PMID: 12460684 DOI: 10.1016/s0005-2728(02)00370-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Intra-subunit interactions in the environment of the iron-sulfur cluster F(X) in Photosystem I (PS I) of Synechocystis sp. PCC 6803 were studied by site-directed and second site suppressor mutations. In subunit PsaB, the cysteine ligand (C565) of F(X) and a conserved aspartate (D566) adjacent to C565 were modified. The resulting mutants D566E, C556S/D566E, C556H/D566E and C565H/D566E did not assemble PS I in the thylakoids of the cyanobacterium. Yet, this is the first report of cells of the second site-suppressor mutant (D566E/L416P) and of second site-directed mutant (C565S/D566E) in PsaB that could grow autotrophically in light and were found to assemble a stable functional PS I containing all three iron-sulfur centers, F(X) and F(A/B). The newly resolved structure of PS I (PDB 1JB0) was used to interpret the functional interactions among the amino acid residues. It is suggested that the stability of F(X) is supported by a salt bridge formed between D566, which is adjacent to the cysteine ligand C565 of the iron-sulfur cluster located on loop hi, and R703 located at the start of loop jk. Hydrogen bond between R703 and D571 at the start of loop hi further stabilizes the arginine. Lengthening of the side by 1.2 A chain in mutation D566E caused destabilization of F(X). The extended side-chain was compensated for by the Fe-O, which is 0.3 A shorter than the Fe-S bond resulting in stabilization of the F(X) in the double mutations C565S/D566E. The suppressor mutation D566E/L416P allowed greater freedom for the salt bridge E566-R703, thus relieving the pressure introduced by the D566E replacement and enabling the formation of F(X). F(X) and R703 are therefore stabilized through short- and long-range interactions of the inter-helical loops between h-i, j-k and f-g, respectively.
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Affiliation(s)
- Ming-Tao Zeng
- Department of Biochemistry, Tel Aviv University, 69978, Tel Aviv, Israel
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22
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Hauska G, Schoedl T, Remigy H, Tsiotis G. The reaction center of green sulfur bacteria(1). BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1507:260-77. [PMID: 11687219 DOI: 10.1016/s0005-2728(01)00200-6] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The composition of the P840-reaction center complex (RC), energy and electron transfer within the RC, as well as its topographical organization and interaction with other components in the membrane of green sulfur bacteria are presented, and compared to the FeS-type reaction centers of Photosystem I and of Heliobacteria. The core of the RC is homodimeric, since pscA is the only gene found in the genome of Chlorobium tepidum which resembles the genes psaA and -B for the heterodimeric core of Photosystem I. Functionally intact RC can be isolated from several species of green sulfur bacteria. It is generally composed of five subunits, PscA-D plus the BChl a-protein FMO. Functional cores, with PscA and PscB only, can be isolated from Prostecochloris aestuarii. The PscA-dimer binds P840, a special pair of BChl a-molecules, the primary electron acceptor A(0), which is a Chl a-derivative and FeS-center F(X). An equivalent to the electron acceptor A(1) in Photosystem I, which is tightly bound phylloquinone acting between A(0) and F(X), is not required for forward electron transfer in the RC of green sulfur bacteria. This difference is reflected by different rates of electron transfer between A(0) and F(X) in the two systems. The subunit PscB contains the two FeS-centers F(A) and F(B). STEM particle analysis suggests that the core of the RC with PscA and PscB resembles the PsaAB/PsaC-core of the P700-reaction center in Photosystem I. PscB may form a protrusion into the cytoplasmic space where reduction of ferredoxin occurs, with FMO trimers bound on both sides of this protrusion. Thus the subunit composition of the RC in vivo should be 2(FMO)(3)(PscA)(2)PscB(PscC)(2)PscD. Only 16 BChl a-, four Chl a-molecules and two carotenoids are bound to the RC-core, which is substantially less than its counterpart of Photosystem I, with 85 Chl a-molecules and 22 carotenoids. A total of 58 BChl a/RC are present in the membranes of green sulfur bacteria outside the chlorosomes, corresponding to two trimers of FMO (42 Bchl a) per RC (16 BChl a). The question whether the homodimeric RC is totally symmetric is still open. Furthermore, it is still unclear which cytochrome c is the physiological electron donor to P840(+). Also the way of NAD(+)-reduction is unknown, since a gene equivalent to ferredoxin-NADP(+) reductase is not present in the genome.
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Affiliation(s)
- G Hauska
- Lehstuhl für Zellbiologie und Pflanzenphysiologie, Universität Regensburg, Germany.
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23
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Vassiliev IR, Antonkine ML, Golbeck JH. Iron-sulfur clusters in type I reaction centers. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1507:139-60. [PMID: 11687212 DOI: 10.1016/s0005-2728(01)00197-9] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Type I reaction centers (RCs) are multisubunit chlorophyll-protein complexes that function in photosynthetic organisms to convert photons to Gibbs free energy. The unique feature of Type I RCs is the presence of iron-sulfur clusters as electron transfer cofactors. Photosystem I (PS I) of oxygenic phototrophs is the best-studied Type I RC. It is comprised of an interpolypeptide [4Fe-4S] cluster, F(X), that bridges the PsaA and PsaB subunits, and two terminal [4Fe-4S] clusters, F(A) and F(B), that are bound to the PsaC subunit. In this review, we provide an update on the structure and function of the bound iron-sulfur clusters in Type I RCs. The first new development in this area is the identification of F(A) as the cluster proximal to F(X) and the resolution of the electron transfer sequence as F(X)-->F(A)-->F(B)-->soluble ferredoxin. The second new development is the determination of the three-dimensional NMR solution structure of unbound PsaC and localization of the equal- and mixed-valence pairs in F(A)(-) and F(B)(-). We provide a survey of the EPR properties and spectra of the iron-sulfur clusters in Type I RCs of cyanobacteria, green sulfur bacteria, and heliobacteria, and we summarize new information about the kinetics of back-reactions involving the iron-sulfur clusters.
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Affiliation(s)
- I R Vassiliev
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 310 South Frear Building, University Park, PA 16802, USA
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24
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Klukas O, Schubert WD, Jordan P, Krau N, Fromme P, Witt HT, Saenger W. Localization of two phylloquinones, QK and QK', in an improved electron density map of photosystem I at 4-A resolution. J Biol Chem 1999; 274:7361-7. [PMID: 10066800 DOI: 10.1074/jbc.274.11.7361] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An improved electron density map of photosystem I from Synechococcus elongatus calculated at 4-A resolution for the first time reveals a second phylloquinone molecule and thereby completes the set of cofactors constituting the electron transfer system of this iron-sulfur type photosynthetic reaction center: six chlorophyll a, two phylloquinones, and three Fe4S4 clusters. The location of the newly identified phylloquinone pair, the individual plane orientations of these molecules, and the resulting distances to other cofactors of the electron transfer system are discussed and compared with those determined by magnetic resonance techniques.
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Affiliation(s)
- O Klukas
- Institut für Kristallographie, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany
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25
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Yang F, Shen G, Schluchter WM, Zybailov BL, Ganago AO, Vassiliev IR, Bryant DA, Golbeck JH. Deletion of the PsaF Polypeptide Modifies the Environment of the Redox-Active Phylloquinone (A1). Evidence for Unidirectionality of Electron Transfer in Photosystem I. J Phys Chem B 1998. [DOI: 10.1021/jp981952i] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fan Yang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Gaozhong Shen
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Wendy M. Schluchter
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Boris L. Zybailov
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Alexander O. Ganago
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Ilya R. Vassiliev
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Donald A. Bryant
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - John H. Golbeck
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
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26
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Polm M, Brettel K. Secondary pair charge recombination in photosystem I under strongly reducing conditions: temperature dependence and suggested mechanism. Biophys J 1998; 74:3173-81. [PMID: 9635770 PMCID: PMC1299657 DOI: 10.1016/s0006-3495(98)78023-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Photoinduced electron transfer in photosystem I (PS I) proceeds from the excited primary electron donor P700 (a chlorophyll a dimer) via the primary acceptor A0 (chlorophyll a) and the secondary acceptor A1 (phylloquinone) to three [4Fe-4S] clusters, Fx, FA, and FB. Prereduction of the iron-sulfur clusters blocks electron transfer beyond A1. It has been shown previously that, under such conditions, the secondary pair P700+A1- decays by charge recombination with t1/2 approximately 250 ns at room temperature, forming the P700 triplet state (3P700) with a yield exceeding 85%. This reaction is unusual, as the secondary pair in other photosynthetic reaction centers recombines much slower and forms directly the singlet ground state rather than the triplet state of the primary donor. Here we studied the temperature dependence of secondary pair recombination in PS I from the cyanobacterium Synechococcus sp. PCC6803, which had been illuminated in the presence of dithionite at pH 10 to reduce all three iron-sulfur clusters. The reaction P700+A1- --> 3P700 was monitored by flash absorption spectroscopy. With decreasing temperature, the recombination slowed down and the yield of 3P700 decreased. In the range between 303 K and 240 K, the recombination rates could be described by the Arrhenius law with an activation energy of approximately 170 meV. Below 240 K, the temperature dependence became much weaker, and recombination to the singlet ground state became the dominating process. To explain the fast activated recombination to the P700 triplet state, we suggest a mechanism involving efficient singlet to triplet spin evolution in the secondary pair, thermally activated repopulation of the more closely spaced primary pair P700+A0- in a triplet spin configuration, and subsequent fast recombination (intrinsic rate on the order of 10(9) s(-1)) forming 3P700.
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Affiliation(s)
- M Polm
- Section de Bioénergétique and CNRS-URA 2096, Département de Biologie Cellulaire et Moléculaire, CEA Saclay, Gif-sur-Yvette, France
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27
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The P700 triplet state in an intact environment detected by ODMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1997. [DOI: 10.1016/s0005-2728(97)00068-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Ostafin AE, Weber S. Quinone exchange at the A1 site in Photosystem I in spinach and cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1997. [DOI: 10.1016/s0005-2728(97)00023-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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Electron transfer and arrangement of the redox cofactors in photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1997. [DOI: 10.1016/s0005-2728(96)00112-0] [Citation(s) in RCA: 380] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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30
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White NTH, Beddard GS, Thorne JRG, Feehan TM, Keyes TE, Heathcote P. Primary Charge Separation and Energy Transfer in the Photosystem I Reaction Center of Higher Plants. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9604709] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nigel T. H. White
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Godfrey S. Beddard
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Jonathan R. G. Thorne
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Tim M. Feehan
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Tia E. Keyes
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Peter Heathcote
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
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31
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Magnetic-field effects on primary reactions in Photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - BIOENERGETICS 1996. [DOI: 10.1016/0005-2728(96)00021-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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32
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Rigby SE, Evans MC, Heathcote P. ENDOR and special triple resonance spectroscopy of A1.- of photosystem 1. Biochemistry 1996; 35:6651-6. [PMID: 8639614 DOI: 10.1021/bi952619x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The photoaccumulated radical state of the photosystem 1 secondary electron acceptor A1, A1.-, has been studied in spinach and the cyanobacterium Anabaena variabilis strain Met27 using electron nuclear double resonance (ENDOR) and electron--nuclear--nuclear special triple (ST) resonance spectroscopies. Spectra of A1.- in both these species are very similar. ENDOR spectra of the phylloquinone anion radical in solvent glass were also obtained. Comparison of the spectra of the in vivo and in vitro radicals shows that A1.- is a phylloquinone anion radical with a distorted electron spin density distribution. Hyperfine couplings to the A1.- methyl group and to two protons hydrogen bonded to the quinone oxygens have been identified using biosynthetic deuteration in A. variabilis. Possible hyperfine coupling to a methylene proton of the phytyl side chain of the quinone has also been identified. These results are compared with those from previous studies of protein-bound semiquinones in the light of the unusual redox potential of A1.
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Affiliation(s)
- S E Rigby
- Department of Biology, University College London, University of London, U.K
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33
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Baba K, Itoh S, Hastings G, Hoshina S. Photoinhibition of Photosystem I electron transfer activity in isolated Photosystem I preparations with different chlorophyll contents. PHOTOSYNTHESIS RESEARCH 1996; 47:121-130. [PMID: 24301820 DOI: 10.1007/bf00016175] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/1995] [Accepted: 11/29/1995] [Indexed: 06/02/2023]
Abstract
Photoinhibition of the light-induced Photosystem I (PS I) electron transfer activity from the reduced dichlorophenol indophenol to methyl viologen was studied. PS I preparations with Chl/P700 ratios of about 180 (PS I-180), 100 (PS I-100) and 40 (PS I(HA)-40) were isolated from spinach thylakoid membranes by the treatments with Triton X-100, followed by sucrose density gradient centrifugation and hydroxylapatite column chromatography. White light irradiation (1.1 × 10(4)μE m(-2) s(-1)) of PS I-180 for 2 hours bleached 50% of the chlorophyll and caused a 58% decrease in the electron transfer activity with virtually no loss of the primary donor, P700. The flash-induced absorbance change showed the decay phase with a half time of about 10 μs that was attributed to the P700 triplet, suggesting that the photoinhibitory light treatment caused the destruction of the PS I acceptor(s), Fx and possibly A1. PS I-100 was similarly photobleached by the irradiation and the electron transfer activity decreased. There was, however, no apparent photoinhibition of the electron transport activity in PS I(HA)-40. Photoinhibition similar to that seen in PS I-180 also occurred in membrane fragments that were isolated without any detergent from a PS II-deficient mutant strain of the cyanobacterium Synechocystis sp. PCC 6803. PS I-180 was not photoinhibited under anaerobic conditions. The production of superoxide and fatty acid hydroperoxide during white light irradiation was significantly greater in PS I-180 than in PS I(HA)-40. The mechanism of photoinhibition in PS I preparations is discussed in relation to the formation of toxic oxygen molecules.
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Affiliation(s)
- K Baba
- Department of Biology, Faculty of Science, Kanazawa University, Kakuma, 920-11, Kanazawa
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Brettel K, Golbeck JH. Spectral and kinetic characterization of electron acceptor A1 in a Photosystem I core devoid of iron-sulfur centers F X, F B and F A. PHOTOSYNTHESIS RESEARCH 1995; 45:183-193. [PMID: 24301530 DOI: 10.1007/bf00015559] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/1995] [Accepted: 07/06/1995] [Indexed: 06/02/2023]
Abstract
The kinetic and spectroscopic properties of the secondary electron acceptor A1 were determined by flash absorption spectroscopy at room and cryogenic temperatures in a Photosystem I (PS I) core devoid of the iron-sulfur clusters FX, FB and FA. It was shown earlier (Warren, P.V., Golbeck, J.H. and Warden, J.T. (1993) Biochemistry 32: 849-857) that the majority of the flash-induced absorbance increase at 820 nm, reflecting formation of P700(+), decays with a t1/2 of 10 μs due to charge recombination between P700(+) and A1 (-). Following A1 (-) directly around 380 nm, where absorbance changes due to the formation of P700(+) are negligible, two major decay components were resolved in this study with t1/2 of ≈ 10 μs and 110 μs at an amplitude ratio of ≈ 2.5:1. The difference spectra between 340 and 490 nm of the two kinetic phases are highly similar, showing absorbance increases from 340 to 400 nm characteristic of the one-electron reduction of the phylloquinone A1. When measured at 10 K, the flash-induced absorbance changes around 380 nm can be fitted with two decay phases of t1/2 ≈ 15 μs and 150 μs at an amplitude ratio ≈ 1:1. The difference spectra of both kinetic phases from 340 to 400 nm are similar to those determined at 298 K and are therefore attributed to charge recombination in the pair P700(+)A1 (-). These results indicate that the backreaction between P700(+) and A1 (-) is multiphasic when FX, FB and FA are removed, and only slightly temperature dependent in the range of 298 K to 10 K.
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Affiliation(s)
- K Brettel
- Section de Bioénergétique (CNRS-URA 1290), DBCM, CEA-Saclay, 91191, Gif-sur-Yvette Cedex, France
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Sonoike K, Terashima I, Iwaki M, Itoh S. Destruction of photosystem I iron-sulfur centers in leaves of Cucumis sativus L. by weak illumination at chilling temperatures. FEBS Lett 1995; 362:235-8. [PMID: 7720879 DOI: 10.1016/0014-5793(95)00254-7] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The activity of photosystem (PS) I in cucumber leaves was selectively inhibited by weak illumination at chilling temperatures with almost no loss of P-700 content and PSII activity. The sites of inactivation in the reducing side of PSI were determined by EPR and flash photolysis. Measurement by EPR showed the destruction of iron-sulfur centers, FX, FA and FB, in parallel with the loss of quantum yield of electron transfer from diaminodurene to NADP+. Flash photolysis showed the increases in the triplet states of P-700 and antenna pigments, along with the decrease in the electron transfer from P-700 to FA/FB. This indicates the increase in the charge recombination between P-700+ and A0-. It is concluded that weak-light treatment of cucumber leaves at chilling temperature destroys FX, FA and FB and possibly A1. This gives the molecular basis for the mechanism of selective PSI photodamage that was recently reported [Sonoike and Terashima (1994) Planta 194, 287-293].
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Affiliation(s)
- K Sonoike
- Department of Biology, Faculty of Science, University of Tokyo, Japan
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Moënne-Loccoz P, Heathcote P, Maclachlan DJ, Berry MC, Davis IH, Evans MC. Path of electron transfer in photosystem 1: direct evidence of forward electron transfer from A1 to Fe-Sx. Biochemistry 1994; 33:10037-42. [PMID: 8060972 DOI: 10.1021/bi00199a030] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Pulsed EPR spectroscopy and selective removal of the iron-sulfur centers in photosystem 1 have been used to study forward electron transfer from the secondary electron acceptor A1. At cryogenic temperatures where forward electron transfer is inhibited, we have observed a g = 2.003 electron spin-echo signal presenting a characteristic phase shift. This out-of-phase signal is attributed to the electron spin-polarized pair P700+/A1-, it decays with t1/e = 23 microseconds, reflecting the recombination reaction. At room temperature the out-of-phase signal is also observed, but it decays with t1/c = 200 ns in untreated photosystem 1, due to forward electron transfer from A1- to one of the iron-sulfur centers. This rate is unchanged in Fe-SA/B-depleted PS1 but is lost when the iron-sulfur center Fe-Sx is removed. In the preparations depleted of all iron-sulfur centers the out-of-phase signal decays with t1/c = 1.3 microseconds, reflecting either the back reaction or the decay of polarization. These results demonstrate that the electron transfer pathway in photosystem 1 is P700-->A1-->Fe-SX-->Fe-SA/B.
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Double-reduction of A1 abolishes the EPR signal attributed to A−1: Evidence for C2 symmetry in the Photosystem I reaction centre. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90030-j] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Sieckmann I, Brettel K, Bock C, van der Est A, Stehlik D. Transient electron paramagnetic resonance of the triplet state of P700 in photosystem I: evidence for triplet delocalization at room temperature. Biochemistry 1993; 32:4842-7. [PMID: 8387818 DOI: 10.1021/bi00069a020] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Spin-polarized EPR spectra of the triplet state of P700, the primary electron donor in photosystem I (PS I), have been measured for the first time at room temperature. The measurements were performed on intact PS I from Synechococcus sp. after prereduction of all iron-sulfur centers and on vitamin K1 depleted PS I from Synechocystis 6803. The two preparations give similar spectra with a polarization pattern which indicates that the triplet state is formed via recombination of a radical pair. The axial and nonaxial zero-field splitting (zfs) parameters are found to be magnitude of D = (284 +/- 15) x 10(-4) cm-1 and magnitude of E = (22 +/- 3) x 10(-4) cm-1, respectively. The E-value is 42% smaller than in monomeric chlorophyll a, while the D-value is nearly the same. Measurements of the Synechocystis 6803 sample at 4.5 K yielded zfs parameters which are identical with those of the chlorophyll monomer, in agreement with previous results. In order to explain this behavior, it is proposed that the triplet excitation is delocalized over the two halves of a chlorophyll dimer at room temperature but appears localized on one half at low temperature. The observed zfs parameters are obtained if (1) the magnetic z-axes of the two chlorophylls are collinear, (2) the magnetic y-axes (and x-axes) of the two chlorophylls make an angle of approximately 55 degrees with each other, and (3) the admixture of charge-transfer states to 3P700 is negligible.(ABSTRACT TRUNCATED AT 250 WORDS)
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Kleinherenbrink F, Ikegami I, Hiraishi A, Otte S, Amesz J. Electron transfer in menaquinone-depleted membranes of Heliobacterium chlorum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90085-t] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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40
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Warren PV, Golbeck JH, Warden JT. Charge recombination between P700+ and A1- occurs directly to the ground state of P700 in a photosystem I core devoid of FX, FB, and FA. Biochemistry 1993; 32:849-57. [PMID: 8422389 DOI: 10.1021/bi00054a016] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The charge recombination between P700+ and electron acceptor A1- was studied by flash kinetic spectroscopy in a photosystem I core devoid of iron-sulfur centers FX, FB, and FA. We showed previously that the majority of the flash-induced absorption change at 820 nm decayed with a 10-microseconds half-time, which we assigned to the disappearance of the P700 triplet formed from the backreaction of P700+ with A1- [Warren, P.V., Parrett, K.G., Warden, J.T., & Golbeck, J.H. (1990) Biochemistry 29, 6545-6550]. We have reinvestigated this assignment in the near-UV, blue, and near-IR wavelength regions. The difference spectrum from 380 to 480 nm and from 720 to 910 nm shows that the P700+ A1- charge recombination is dominated by the P700 cation rather than the P700 triplet. Accordingly, the 10-microseconds kinetic transient represents the direct backreaction of P700+ with A1-, which repopulates the ground state of P700. This is unlike a P700-FA/FB complex where, in the presence of reduced FX-, FB-, and FA-, the P700+ A1- charge recombination populates the P700 triplet state [Sétif, P., & Bottin, H. (1989) Biochemistry 28, 2689-2697]. The A1 acceptor is highly susceptible to disruption by detergents in the absence of iron-sulfur center FX. The addition of 0.1% Triton X-100 to the P700-A1 core leads to a approximately 2.5-fold increase in the magnitude of the flash-induced absorption change at 780 nm; thereafter, 85% of the absorption change decays with a 25-ns half-time and 15% decays with a 3-microseconds half-time.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P V Warren
- Department of Biochemistry, University of Nebraska, Lincoln 68583-0718
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Reconstitution and exchange of quinones in the A1 site of Photosystem I. An electron spin polarization electron paramagnetic resonance study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1992. [DOI: 10.1016/0005-2728(92)90087-i] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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42
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Searle GF, Schaafsma TJ. Fluorescence detected magnetic resonance of the primary donor and inner core antenna chlorophyll in Photosystem I reaction centre protein: Sign inversion and energy transfer. PHOTOSYNTHESIS RESEARCH 1992; 32:193-206. [PMID: 24408360 DOI: 10.1007/bf00034795] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/1992] [Accepted: 03/24/1992] [Indexed: 05/28/2023]
Abstract
The Photosystem I reaction centre protein CP1, isolated from barley using polyacrylamide gel electrophoresis showed an EPR (Electron Paramgnetic Resonance) spectrum with the polarisation pattern AEEAAE, typical of the primary donor triplet state (3)P700, created via radical pair formation and recombination. (3)P700 could also be detected by Fluorescence Detected Magnetic Resonance (FDMR) at λf > 700 nm even in the presence of a large number of chlorophyll antennae. Its zero field splitting parameters, D=282.5×10(-4) cm(-1) and E=38.5×10(-4) cm(-1), were independent of the detection wavelength, and agreed with ADMR (Absorption Detected Magnetic Resonance) and EPR values. The signs of the (3)P700 D+E and D-E transitions were positive (increase in fluorescence intensity on applying a resonance microwave field). In contrast, in the emission band 685 < λf < 700 nm FDMR spectra with negative D+E and D-E transitions were detected, and the D value was wavelength-dependent. These FDMR results support an excitation energy transfer model for CP1, derived from time-resolved fluorescence studies, in which two chlorophyll antenna forms are distinguished, with fluorescence at 685 < λf < 700 nm (inner core antennae, F690), and λf > 700 nm (low energy antenna sites, F720), in addition to the P700. The FDMR spectrum in F690 emission can be interpreted as that of (3)P700, observed via reverse singlet excitation energy transfer and added to the FDMR spectrum of the antenna triplet states generated via intramolecular intersystem crossing. This would indicate that reversible energy transfer between F690 and P700 occurs even at 4.2 K.
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Affiliation(s)
- G F Searle
- Department of Molecular Physics, Agricultural University, Dreijenlaan 3, 6703 HA, Wageningen, The Netherlands
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Trost JT, Brune DC, Blankenship RE. Protein sequences and redox titrations indicate that the electron acceptors in reaction centers from heliobacteria are similar to Photosystem I. PHOTOSYNTHESIS RESEARCH 1992; 32:11-22. [PMID: 24408151 DOI: 10.1007/bf00028794] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/1991] [Accepted: 12/02/1991] [Indexed: 06/03/2023]
Abstract
Photosynthetic reaction centers isolated from Heliobacillus mobilis exhibit a single major protein on SDS-PAGE of 47 000 Mr. Attempts to sequence the reaction center polypeptide indicated that the N-terminus is blocked. After enzymatic and chemical cleavage, four peptide fragments were sequenced from the Heliobacillus mobilis apoprotein. Only one of these sequences showed significant specific similarity to any of the protein and deduced protein sequences in the GenBank data base. This fragment is identical with 56% of the residues, including both cysteines, found in the highly conserved region that is proposed to bind iron-sulfur center FX in the Photosystem I reaction center peptide that is the psaB gene product. The similarity to the psaA gene product in this region is 48%.Redox titrations of laser-flash-induced photobleaching with millisecond decay kinetics on isolated reaction centers from Heliobacterium gestii indicate a midpoint potential of -414 mV with n=2 titration behavior. In membranes, the behavior is intermediate between n=1 and n=2, and the apparent midpoint potential is -444 mV. This is compared to the behavior in Photosystem I, where the intermediate electron acceptor A1, thought to be a phylloquinone molecule, has been proposed to undergo a double reduction at low redox potentials in the presence of viologen redox mediators.These results strongly suggest that the acceptor side electron transfer system in reaction centers from heliobacteria is indeed analogous to that found in Photosystem I. The sequence similarities indicate that the divergence of the heliobacteria from the Photosystem I line occurred before the gene duplication and subsequent divergence that lead to the heterodimeric protein core of the Photosystem I reaction center.
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Affiliation(s)
- J T Trost
- Department of Chemistry and Biochemistry, Center for the Study of Early Events in Photosynthesis, Arizona State Univeristy, 85287-1604, Tempe, AZ, USA
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44
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Nitschke W, Rutherford AW. Photosynthetic reaction centres: variations on a common structural theme? Trends Biochem Sci 1991; 16:241-5. [PMID: 1926331 DOI: 10.1016/0968-0004(91)90095-d] [Citation(s) in RCA: 174] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
From their hybrid properties, the reaction centres of green sulphur bacteria and heliobacteria seem to be the missing links between the two branches of the reaction centre family, typified by higher plant photosystem I and the purple bacterial reaction centre. This suggests that all of the diverse types of photosynthetic reaction centres have closer structural resemblances than was previously thought.
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Affiliation(s)
- W Nitschke
- Département de Biologie Cellulaire et Moléculaire, CEN-Saclay, Gif sur Yvette, France
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45
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Sieckman I, van der Est A, Bottin H, Sétif P, Stehlik D. Nanosecond electron transfer kinetics in photosystem I following substitution of quinones for vitamin K1 as studied by time resolved EPR. FEBS Lett 1991; 284:98-102. [PMID: 1647977 DOI: 10.1016/0014-5793(91)80771-t] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Room temperature transient EPR spectra of photosystem I (PS I) particles from Synechocystis 6803 are presented. Native PS I samples and preparations depleted in the A1-acceptor site by solvent extraction and then reconstituted with the quinones (Q) vitamin K1 (VK1), duroquinone (DQ and DQd12) and naphthoquinone (NQ) have been studied. Sequential electron transfer to P700+A1- (FeS) and P700+A1 (FeS)- is recovered only with VK1. With DQ and NQ electron transfer is restored to form the radical pair P700+Q- as specified by a characteristic electron spin polarization (ESP)-pattern, but further electron transfer is either slowed down or blocked. A qualitative analysis of the K-band spectrum suggests that the orientation of reconstituted NQ in PS I is different from the native acceptor A1 = VK1.
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Affiliation(s)
- I Sieckman
- Fachbereich Physik, Freie Universität Berlin, Germany
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46
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Bottin H, Sétif P. Inhibition of electron transfer from A0 to A1 in Photosystem I after treatment in darkness at low redox potential. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(05)80144-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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47
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Kleinherenbrink FA, Aartsma TJ, Amesz J. Charge separation and formation of bacteriochlorophyll triplets in Heliobacterium chlorum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(05)80146-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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48
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Budil DE, Thurnauer MC. The chlorophyll triplet state as a probe of structure and function in photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1057:1-41. [PMID: 1849002 DOI: 10.1016/s0005-2728(05)80081-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- D E Budil
- Baker Laboratory of Chemistry, Cornell University, Ithaca, NY 14850
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49
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Knaff DB, Hirasawa M. Ferredoxin-dependent chloroplast enzymes. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1056:93-125. [PMID: 1671559 DOI: 10.1016/s0005-2728(05)80277-4] [Citation(s) in RCA: 198] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- D B Knaff
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409-1061
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50
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Sétif P, Brettel K. Photosystem I photochemistry under highly reducing conditions: Study of the P700 triplet state formation from the secondary radical pair (P700+−A−1). BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1990. [DOI: 10.1016/0005-2728(90)90152-t] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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