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Agustinus B, Gillam EMJ. Solar-powered P450 catalysis: Engineering electron transfer pathways from photosynthesis to P450s. J Inorg Biochem 2023; 245:112242. [PMID: 37187017 DOI: 10.1016/j.jinorgbio.2023.112242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/17/2023] [Accepted: 04/27/2023] [Indexed: 05/17/2023]
Abstract
With the increasing focus on green chemistry, biocatalysis is becoming more widely used in the pharmaceutical and other chemical industries for sustainable production of high value and structurally complex chemicals. Cytochrome P450 monooxygenases (P450s) are attractive biocatalysts for industrial application due to their ability to transform a huge range of substrates in a stereo- and regiospecific manner. However, despite their appeal, the industrial application of P450s is limited by their dependence on costly reduced nicotinamide adenine dinucleotide phosphate (NADPH) and one or more auxiliary redox partner proteins. Coupling P450s to the photosynthetic machinery of a plant allows photosynthetically-generated electrons to be used to drive catalysis, overcoming this cofactor dependency. Thus, photosynthetic organisms could serve as photobioreactors with the capability to produce value-added chemicals using only light, water, CO2 and an appropriate chemical as substrate for the reaction/s of choice, yielding new opportunities for producing commodity and high-value chemicals in a carbon-negative and sustainable manner. This review will discuss recent progress in using photosynthesis for light-driven P450 biocatalysis and explore the potential for further development of such systems.
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Affiliation(s)
- Bernadius Agustinus
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane 4072, Australia
| | - Elizabeth M J Gillam
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane 4072, Australia.
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2
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Zhang S, Zou B, Cao P, Su X, Xie F, Pan X, Li M. Structural insights into photosynthetic cyclic electron transport. MOLECULAR PLANT 2023; 16:187-205. [PMID: 36540023 DOI: 10.1016/j.molp.2022.12.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/17/2022] [Accepted: 12/18/2022] [Indexed: 06/17/2023]
Abstract
During photosynthesis, light energy is utilized to drive sophisticated biochemical chains of electron transfers, converting solar energy into chemical energy that feeds most life on earth. Cyclic electron transfer/flow (CET/CEF) plays an essential role in efficient photosynthesis, as it balances the ATP/NADPH ratio required in various regulatory and metabolic pathways. Photosystem I, cytochrome b6f, and NADH dehydrogenase (NDH) are large multisubunit protein complexes embedded in the thylakoid membrane of the chloroplast and key players in NDH-dependent CEF pathway. Furthermore, small mobile electron carriers serve as shuttles for electrons between these membrane protein complexes. Efficient electron transfer requires transient interactions between these electron donors and acceptors. Structural biology has been a powerful tool to advance our knowledge of this important biological process. A number of structures of the membrane-embedded complexes, soluble electron carrier proteins, and transient complexes composed of both have now been determined. These structural data reveal detailed interacting patterns of these electron donor-acceptor pairs, thus allowing us to visualize the different parts of the electron transfer process. This review summarizes the current state of structural knowledge of three membrane complexes and their interaction patterns with mobile electron carrier proteins.
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Affiliation(s)
- Shumeng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Baohua Zou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Peng Cao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Xiaodong Su
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Fen Xie
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Xiaowei Pan
- College of Life Science, Capital Normal University, Beijing, China
| | - Mei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
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3
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Smolinski SL, Lubner CE, Guo Z, Artz JH, Brown KA, Mulder DW, King PW. The influence of electron utilization pathways on photosystem I photochemistry in Synechocystis sp. PCC 6803. RSC Adv 2022; 12:14655-14664. [PMID: 35702219 PMCID: PMC9109680 DOI: 10.1039/d2ra01295b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 05/06/2022] [Indexed: 01/24/2023] Open
Abstract
The capacity of cyanobacteria to adapt to highly dynamic photon flux and nutrient availability conditions results from controlled management and use of reducing power, and is a major contributing factor to the efficiency of photosynthesis in aquatic environments. The response to changing conditions includes modulating gene expression and protein-protein interactions that serve to adjust the use of electron flux and mechanisms that control photosynthetic electron transport (PET). In this regard, the photochemical activity of photosystem I (PSI) reaction centers can support balancing of cyclic (CEF) and linear electron flow (LEF), and the coupling of redox carriers for use by electron utilization pathways. Therefore, changes in the utilization of reducing power might be expected to result in compensating changes at PSI as a means to support balance of electron flux. To understand this functional relationship, we investigated the properties of PSI and its photochemical activity in cells that lack flavodiiron 1 catalyzed oxygen reduction activity (ORR1). In the absence of ORR1, the oxygen evolution and consumption rates declined together with a shift in the oligomeric form of PSI towards monomers. The effect of these changes on PSI energy and electron transfer properties was examined in isolated trimer and monomer fractions of PSI reaction centers. Collectively, the results demonstrate that PSI photochemistry is modulated through coordination with the depletion of electron demand in the absence of ORR1.
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Affiliation(s)
- Sharon L. Smolinski
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Carolyn E. Lubner
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Zhanjun Guo
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Jacob H. Artz
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Katherine A. Brown
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - David W. Mulder
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Paul W. King
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
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Szewczyk S, Goyal A, Abram M, Burdziński G, Kargul J, Gibasiewicz K. Electron Transfer in a Bio-Photoelectrode Based on Photosystem I Multilayer Immobilized on the Conducting Glass. Int J Mol Sci 2022; 23:ijms23094774. [PMID: 35563164 PMCID: PMC9100268 DOI: 10.3390/ijms23094774] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 04/13/2022] [Accepted: 04/18/2022] [Indexed: 02/07/2023] Open
Abstract
A film of ~40 layers of partially oriented photosystem I (PSI) complexes isolated from the red alga Cyanidioschyzon merolae formed on the conducting glass through electrodeposition was investigated by time-resolved absorption spectroscopy and chronoamperometry. The experiments were performed at a range of electric potentials applied to the film and at different compositions of electrolyte solution being in contact with the film. The amount of immobilized proteins supporting light-induced charge separation (active PSI) ranged from ~10%, in the absence of any reducing agents (redox compounds or low potential), to ~20% when ascorbate and 2,6-dichlorophenolindophenol were added, and to ~35% when the high negative potential was additionally applied. The origin of the large fraction of permanently inactive PSI (65–90%) was unclear. Both reducing agents increased the subpopulation of active PSI complexes, with the neutral P700 primary electron donor, by reducing significant fractions of the photo-oxidized P700 species. The efficiencies of light-induced charge separation in the PSI film (10–35%) did not translate into an equally effective generation of photocurrent, whose internal quantum efficiency reached the maximal value of 0.47% at the lowest potentials. This mismatch indicates that the vast majority of the charge-separated states in multilayered PSI complexes underwent charge recombination.
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Affiliation(s)
- Sebastian Szewczyk
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland; (S.S.); (A.G.); (G.B.)
| | - Alice Goyal
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland; (S.S.); (A.G.); (G.B.)
| | - Mateusz Abram
- Solar Fuels Laboratory, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland;
- Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Gotard Burdziński
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland; (S.S.); (A.G.); (G.B.)
| | - Joanna Kargul
- Solar Fuels Laboratory, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland;
- Correspondence: (J.K.); (K.G.); Tel.: +48-22-5543760 (J.K.); +48-61-8296390 (K.G.)
| | - Krzysztof Gibasiewicz
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland; (S.S.); (A.G.); (G.B.)
- Correspondence: (J.K.); (K.G.); Tel.: +48-22-5543760 (J.K.); +48-61-8296390 (K.G.)
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5
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Ali F, Shafaa MW, Amin M. Computational Approach for Probing Redox Potential for Iron-Sulfur Clusters in Photosystem I. BIOLOGY 2022; 11:biology11030362. [PMID: 35336736 PMCID: PMC8945787 DOI: 10.3390/biology11030362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 11/16/2022]
Abstract
Photosystem I is a light-driven electron transfer device. Available X-ray crystal structure from Thermosynechococcus elongatus showed that electron transfer pathways consist of two nearly symmetric branches of cofactors converging at the first iron-sulfur cluster FX, which is followed by two terminal iron-sulfur clusters FA and FB. Experiments have shown that FX has lower oxidation potential than FA and FB, which facilitates the electron transfer reaction. Here, we use density functional theory and Multi-Conformer Continuum Electrostatics to explain the differences in the midpoint Em potentials of the FX, FA and FB clusters. Our calculations show that FX has the lowest oxidation potential compared to FA and FB due to strong pairwise electrostatic interactions with surrounding residues. These interactions are shown to be dominated by the bridging sulfurs and cysteine ligands, which may be attributed to the shorter average bond distances between the oxidized Fe ion and ligating sulfurs for FX compared to FA and FB. Moreover, the electrostatic repulsion between the 4Fe-4S clusters and the positive potential of the backbone atoms is lowest for FX compared to both FA and FB. These results agree with the experimental measurements from the redox titrations of low-temperature EPR signals and of room temperature recombination kinetics.
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Affiliation(s)
- Fedaa Ali
- Medical Biophysics Division, Department of Physics, Faculty of Science, Helwan University, Cairo 11795, Egypt; (F.A.); (M.W.S.)
- Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996, USA
| | - Medhat W. Shafaa
- Medical Biophysics Division, Department of Physics, Faculty of Science, Helwan University, Cairo 11795, Egypt; (F.A.); (M.W.S.)
| | - Muhamed Amin
- Department of Sciences, University College Groningen, University of Groningen, Hoendiepskade 23/24, 9718 BG Groningen, The Netherlands
- Universiteit Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9718 BG Groningen, The Netherlands
- Department of Physics, City College of New York, City University of New York, New York, NY 10031, USA
- Correspondence:
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Gisriel CJ, Flesher DA, Shen G, Wang J, Ho MY, Brudvig GW, Bryant DA. Structure of a photosystem I-ferredoxin complex from a marine cyanobacterium provides insights into far-red light photoacclimation. J Biol Chem 2022; 298:101408. [PMID: 34793839 PMCID: PMC8689207 DOI: 10.1016/j.jbc.2021.101408] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 01/08/2023] Open
Abstract
Far-red light photoacclimation exhibited by some cyanobacteria allows these organisms to use the far-red region of the solar spectrum (700-800 nm) for photosynthesis. Part of this process includes the replacement of six photosystem I (PSI) subunits with isoforms that confer the binding of chlorophyll (Chl) f molecules that absorb far-red light (FRL). However, the exact sites at which Chl f molecules are bound are still challenging to determine. To aid in the identification of Chl f-binding sites, we solved the cryo-EM structure of PSI from far-red light-acclimated cells of the cyanobacterium Synechococcus sp. PCC 7335. We identified six sites that bind Chl f with high specificity and three additional sites that are likely to bind Chl f at lower specificity. All of these binding sites are in the core-antenna regions of PSI, and Chl f was not observed among the electron transfer cofactors. This structural analysis also reveals both conserved and nonconserved Chl f-binding sites, the latter of which exemplify the diversity in FRL-PSI among species. We found that the FRL-PSI structure also contains a bound soluble ferredoxin, PetF1, at low occupancy, which suggests that ferredoxin binds less transiently than expected according to the canonical view of ferredoxin-binding to facilitate electron transfer. We suggest that this may result from structural changes in FRL-PSI that occur specifically during FRL photoacclimation.
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Affiliation(s)
| | - David A Flesher
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Jimin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Ming-Yang Ho
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA.
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7
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Kurashov V, Milanovsky G, Luo L, Martin A, Semenov AY, Savikhin S, Cherepanov DA, Golbeck JH, Xu W. Conserved residue PsaB-Trp673 is essential for high-efficiency electron transfer between the phylloquinones and the iron-sulfur clusters in Photosystem I. PHOTOSYNTHESIS RESEARCH 2021; 148:161-180. [PMID: 33991284 DOI: 10.1007/s11120-021-00839-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
Despite the high level of symmetry between the PsaA and PsaB polypeptides in Photosystem I, some amino acids pairs are strikingly different, such as PsaA-Gly693 and PsaB-Trp673, which are located near a cluster of 11 water molecules between the A1A and A1B quinones and the FX iron-sulfur cluster. In this work, we changed PsaB-Trp673 to PsaB-Phe673 in Synechocystis sp. PCC 6803. The variant contains ~ 85% of wild-type (WT) levels of Photosystem I but is unable to grow photoautotrophically. Both time-resolved and steady-state optical measurements show that in the PsaB-W673F variant less than 50% of the electrons reach the terminal iron-sulfur clusters FA and FB; the majority of the electrons recombine from A1A- and A1B-. However, in those reaction centers which pass electrons forward the transfer is heterogeneous: a minor population shows electron transfer rates from A1A- and A1B- to FX slightly slower than that of the WT, whereas a major population shows forward electron transfer rates to FX slowed to the ~ 10 µs time range. Competition between relatively similar forward and backward rates of electron transfer from the quinones to the FX cluster account for the relatively low yield of long-lived charge separation in the PsaB-W673F variant. A higher water content and its increased mobility observed in MD simulations in the interquinone cavity of the PsaB-W673F variant shifts the pK of PsaB-Asp575 and allows its deprotonation in situ. The heterogeneity found may be rooted in protonation state of PsaB-Asp575, which controls whether electron transfer can proceed beyond the phylloquinone cofactors.
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Affiliation(s)
- Vasily Kurashov
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - George Milanovsky
- A.N. Belozersky Institute of Physical-Chemical Biology, Moscow State University, Leninskie Gory, 1, Building 40, Moscow, Russia, 119992
| | - Lujun Luo
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA
| | - Antoine Martin
- Department of Physics, Purdue University, West Lafayette, IN, USA
| | - Alexey Yu Semenov
- A.N. Belozersky Institute of Physical-Chemical Biology, Moscow State University, Leninskie Gory, 1, Building 40, Moscow, Russia, 119992
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina st, 4, Moscow, Russia, 117977
| | - Sergei Savikhin
- Department of Physics, Purdue University, West Lafayette, IN, USA
| | - Dmitry A Cherepanov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina st, 4, Moscow, Russia, 117977.
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA.
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA.
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8
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Gao X, Bowler C, Kazamia E. Iron metabolism strategies in diatoms. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:2165-2180. [PMID: 33693565 PMCID: PMC7966952 DOI: 10.1093/jxb/eraa575] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 03/03/2021] [Indexed: 05/28/2023]
Abstract
Diatoms are one of the most successful group of photosynthetic eukaryotes in the contemporary ocean. They are ubiquitously distributed and are the most abundant primary producers in polar waters. Equally remarkable is their ability to tolerate iron deprivation and respond to periodic iron fertilization. Despite their relatively large cell sizes, diatoms tolerate iron limitation and frequently dominate iron-stimulated phytoplankton blooms, both natural and artificial. Here, we review the main iron use strategies of diatoms, including their ability to assimilate and store a range of iron sources, and the adaptations of their photosynthetic machinery and architecture to iron deprivation. Our synthesis relies on published literature and is complemented by a search of 82 diatom transcriptomes, including information collected from seven representatives of the most abundant diatom genera in the world's oceans.
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Affiliation(s)
- Xia Gao
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Chris Bowler
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Elena Kazamia
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
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9
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Takei T, Ando T, Takao T, Ohnishi Y, Kurisu G, Iwaoka M, Hojo H. Chemical synthesis of ferredoxin with 4 selenocysteine residues using a segment condensation method. Chem Commun (Camb) 2020; 56:14239-14242. [PMID: 33118552 DOI: 10.1039/d0cc06252a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ferredoxin (Fd) is an electron carrier protein containing a [2Fe-2S] cluster. In this paper, we synthesized Se-Fd, in which four Cys residues coordinated to the cluster are substituted to selenocysteine. After the one-pot segment coupling by the thioester method, followed by deprotection and cluster loading, the desired Se-Fd was successfully obtained.
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Affiliation(s)
- Toshiki Takei
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan.
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10
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Gideon DA, Nirusimhan V, Manoj KM. Are plastocyanin and ferredoxin specific electron carriers or generic redox capacitors? Classical and murburn perspectives on two photosynthetic proteins. J Biomol Struct Dyn 2020; 40:1995-2009. [PMID: 33073701 DOI: 10.1080/07391102.2020.1835715] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In the light reaction of oxygenic photosynthesis, plastocyanin (PC) and ferredoxins (Fd) are small/diffusible redox-active proteins playing key roles in electron transfer/transport phenomena. In the Z-scheme mechanistic purview, they are considered as specific affinity binding-based electron-relay agents, linking the functions of Cytochrome b6f (Cyt. b6f), Photosystem I (PS I) and Fd:NADPH oxidoreductase (FNR). The murburn explanation for photolytic photophosphorylation deems PC/Fd as generic 'redox capacitors', temporally accepting and releasing one-electron equivalents in reaction milieu. Herein, we explore the two theories with respect to structural, distributional and functional aspects of PC/Fd. Amino acid residues located on the surface loci of key patches of PC/Fd vary in electrostatic/contour (topography) signatures. Crystal structures of four different complexes each of Cyt.f-PC and Fd-FNR show little conservation in the contact-surfaces, thereby discrediting 'affinity binding-based electron transfers (ET)' as an evolutionary logic. Further, thermodynamic and kinetic data of wildtype and mutant proteins interactions do not align with Z-scheme. Furthermore, micromolar physiological concentrations of PC and the non-conducive architecture of chloroplasts render the classical model untenable. In the murburn model, as PC is optional, the observation that plants lacking PC survive and grow is justified. Further, the low physiological concentration/distribution of PC in chloroplast lumen/stroma is supported by murburn equilibriums, as higher concentrations would limit electron transfers. Thus, structural evidence, interactive dynamics with redox partners and physiological distribution/role of PC/Fd support the murburn perspective that these proteins serve as generic redox-capacitors in chloroplasts.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Daniel Andrew Gideon
- Department of Biochemistry, Satyamjayatu: The Science & Ethics Foundation, Palakkad, India.,Department of Biotechnology and Bioinformatics, Bishop Heber College (Autonomous), Tiruchirappalli, India
| | - Vijay Nirusimhan
- Department of Biotechnology and Bioinformatics, Bishop Heber College (Autonomous), Tiruchirappalli, India
| | - Kelath Murali Manoj
- Department of Biochemistry, Satyamjayatu: The Science & Ethics Foundation, Palakkad, India
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11
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Rubredoxin from the green sulfur bacterium Chlorobaculum tepidum donates a redox equivalent to the flavodiiron protein in an NAD(P)H dependent manner via ferredoxin-NAD(P) + oxidoreductase. Arch Microbiol 2020; 203:799-808. [PMID: 33051772 DOI: 10.1007/s00203-020-02079-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 09/24/2020] [Accepted: 10/01/2020] [Indexed: 10/23/2022]
Abstract
The green sulfur bacterium, Chlorobaculum tepidum, is an anaerobic photoautotroph that performs anoxygenic photosynthesis. Although genes encoding rubredoxin (Rd) and a putative flavodiiron protein (FDP) were reported in the genome, a gene encoding putative NADH-Rd oxidoreductase is not identified. In this work, we expressed and purified the recombinant Rd and FDP and confirmed dioxygen reductase activity in the presence of ferredoxin-NAD(P)+ oxidoreductase (FNR). FNR from C. tepidum and Bacillus subtilis catalyzed the reduction of Rd at rates comparable to those reported for NADH-Rd oxidoreductases. Also, we observed substrate inhibition at high concentrations of NADPH similar to that observed with ferredoxins. In the presence of NADPH, B. subtilis FNR and Rd, FDP promoted dioxygen reduction at rates comparable to those reported for other bacterial FDPs. Taken together, our results suggest that Rd and FDP participate in the reduction of dioxygen in C. tepidum and that FNR can promote the reduction of Rd in this bacterium.
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12
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Sétif P, Boussac A, Krieger-Liszkay A. Near-infrared in vitro measurements of photosystem I cofactors and electron-transfer partners with a recently developed spectrophotometer. PHOTOSYNTHESIS RESEARCH 2019; 142:307-319. [PMID: 31482263 DOI: 10.1007/s11120-019-00665-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/20/2019] [Indexed: 06/10/2023]
Abstract
A kinetic-LED-array-spectrophotometer (Klas) was recently developed for measuring in vivo redox changes of P700, plastocyanin (PCy), and ferredoxin (Fd) in the near-infrared (NIR). This spectrophotometer is used in the present work for in vitro light-induced measurements with various combinations of photosystem I (PSI) from tobacco and two different cyanobacteria, spinach plastocyanin, cyanobacterial cytochrome c6 (cyt. c6), and Fd. It is shown that cyt. c6 oxidation contributes to the NIR absorption changes. The reduction of (FAFB), the terminal electron acceptor of PSI, was also observed and the shape of the (FAFB) NIR difference spectrum is similar to that of Fd. The NIR difference spectra of the electron-transfer cofactors were compared between different organisms and to those previously measured in vivo, whereas the relative absorption coefficients of all cofactors were determined by using single PSI turnover conditions. Thus, the (840 nm minus 965 nm) extinction coefficients of the light-induced species (oxidized minus reduced for PC and cyt. c6, reduced minus oxidized for (FAFB), and Fd) were determined with values of 0.207 ± 0.004, - 0.033 ± 0.006, - 0.036 ± 0.008, and - 0.021 ± 0.005 for PCy, cyt. c6, (FAFB) (single reduction), and Fd, respectively, by taking a reference value of + 1 for P700+. The fact that the NIR P700 coefficient is larger than that of PCy and much larger than that of other contributing species, combined with the observed variability in the NIR P700 spectral shape, emphasizes that deconvolution of NIR signals into different components requires a very precise determination of the P700 spectrum.
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Affiliation(s)
- Pierre Sétif
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-Sur-Yvette Cedex, France.
| | - Alain Boussac
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-Sur-Yvette Cedex, France
| | - Anja Krieger-Liszkay
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-Sur-Yvette Cedex, France
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13
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An alternative plant-like cyanobacterial ferredoxin with unprecedented structural and functional properties. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:148084. [DOI: 10.1016/j.bbabio.2019.148084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/02/2019] [Accepted: 09/08/2019] [Indexed: 11/23/2022]
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14
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Bertsova YV, Kulik LV, Mamedov MD, Baykov AA, Bogachev AV. Flavodoxin with an air-stable flavin semiquinone in a green sulfur bacterium. PHOTOSYNTHESIS RESEARCH 2019; 142:127-136. [PMID: 31302833 DOI: 10.1007/s11120-019-00658-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
Flavodoxins are small proteins with a non-covalently bound FMN that can accept two electrons and accordingly adopt three redox states: oxidized (quinone), one-electron reduced (semiquinone), and two-electron reduced (quinol). In iron-deficient cyanobacteria and algae, flavodoxin can substitute for ferredoxin as the electron carrier in the photosynthetic electron transport chain. Here, we demonstrate a similar function for flavodoxin from the green sulfur bacterium Chlorobium phaeovibrioides (cp-Fld). The expression of the cp-Fld gene, found in a close proximity with the genes for other proteins associated with iron transport and storage, increased in a low-iron medium. cp-Fld produced in Escherichia coli exhibited the optical, ERP, and electron-nuclear double resonance spectra that were similar to those of known flavodoxins. However, unlike all other flavodoxins, cp-Fld exhibited unprecedented stability of FMN semiquinone to oxidation by air and difference in midpoint redox potentials for the quinone-semiquinone and semiquinone-quinol couples (- 110 and - 530 mV, respectively). cp-Fld could be reduced by pyruvate:ferredoxin oxidoreductase found in the membrane-free extract of Chl. phaeovibrioides cells and photo-reduced by the photosynthetic reaction center found in membrane vesicles from these cells. The green sulfur bacterium Chl. phaeovibrioides appears thus to be a new type of the photosynthetic organisms that can use flavodoxin as an alternative electron carrier to cope with iron deficiency.
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Affiliation(s)
- Yulia V Bertsova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119234
| | - Leonid V Kulik
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk, Russia, 630090
- Novosibirsk State University, Novosibirsk, Russia, 630090
| | - Mahir D Mamedov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119234
| | - Alexander A Baykov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119234
| | - Alexander V Bogachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119234.
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15
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Binding of ferredoxin NADP + oxidoreductase (FNR) to plant photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:689-698. [PMID: 31336103 DOI: 10.1016/j.bbabio.2019.07.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/11/2019] [Accepted: 07/18/2019] [Indexed: 12/17/2022]
Abstract
The binding of FNR to PSI has been postulated long ago, however, a clear evidence is still missing. In this work, using isothermal titration calorimetry (ITC), we found that FNR binds to photosystem I with its light harvesting complex I (PSI-LHCI) from C. reinhardtii with a 1:1 stoichiometry, a Kd of ~0.8 μM and ∆H of -20.7 kcal/mol. Titrations at different temperatures were used to determine the heat capacity change, ∆CP, of the binding, through which the size of the interface area between the proteins was assessed as ~3000 Å2. In a different set of ITC experiments, introduction of various sucrose concentrations was used to estimate that ~95 water molecules are released to the solvent. These observations support the notion of a binding site shared by few of the photosystem I - light harvesting complex I (PSI-LHCI) subunits in addition to PsaE. Based on these results, a hypothetical model was built for the binding site of FNR at PSI, using known crystallographic structures of: cyanobacterial PSI in complex with ferredoxin (Fd), plant PSI-LHCI and Fd:FNR complex from cyanobacteria. FNR binding site location is proposed to be at the foot of the stromal ridge and above the inner LHCI belt. It is expected to form contacts with PsaE, PsaB, PsaF and at least one of the LHCI. In addition, a ~4.5-fold increased affinity between FNR and PSI-LHCI under crowded 1 M sucrose environment led us to conclude that in C. reinhardtii FNR also functions as a subunit of PSI-LHCI.
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16
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Santabarbara S, Casazza AP. Kinetics and Energetics of Phylloquinone Reduction in Photosystem I: Insight From Modeling of the Site Directed Mutants. FRONTIERS IN PLANT SCIENCE 2019; 10:852. [PMID: 31312208 PMCID: PMC6614487 DOI: 10.3389/fpls.2019.00852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/13/2019] [Indexed: 06/10/2023]
Abstract
Two phylloquinone molecules (A 1), one being predominantly coordinated by PsaA subunit residues (A 1A) the other by those of PsaB (A 1B), act as intermediates in the two parallel electron transfer chains of Photosystem I. The oxidation kinetics of the two phyllosemiquinones by the iron-sulfur cluster FX differ by approximately one order of magnitude, with A 1 A - being oxidized in about 200 ns and A 1 B - in about 20 ns. These differences are generally explained in terms of asymmetries in the driving force for FX reduction on the two electron transfer chains. Site directed mutations of conserved amino acids composing the A 1 binding site have been engineered on both reaction center subunits, and proved to affect selectively the oxidation lifetime of either A 1 A - , for PsaA mutants, or A 1 B - , for PsaB mutants. The mutation effects are here critically reviewed, also by novel modeling simulations employing the tunneling formalism to estimate the electron transfer rates. Three main classes of mutation effects are in particular addressed: (i) those leading to an acceleration, (ii) those leading to a moderated slowing (~5-folds), and (iii) those leading to a severe slowing (>20-folds) of the kinetics. The effect of specific amino acid perturbations contributing to the poising of the phylloquinones redox potential and, in turn, to PSI functionality, is discussed.
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Affiliation(s)
- Stefano Santabarbara
- Centre for Fundamental Research in Photosynthesis, Vergiate, Italy
- Photosynthesis Research Unit, Centro Studi sulla Biologia Cellulare e Molecolare delle Piante, Milan, Italy
| | - Anna Paola Casazza
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Milan, Italy
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17
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Abstract
Bacterial biofilms are ubiquitous in natural environments and play an important role in many clinical, industrial, and ecological settings. Although much is known about the transcriptional regulatory networks that control biofilm formation in model bacteria such as Bacillus subtilis, very little is known about the role of metabolism in this complex developmental process. To address this important knowledge gap, we performed a time-resolved analysis of the metabolic changes associated with bacterial biofilm development in B. subtilis by combining metabolomic, transcriptomic, and proteomic analyses. Here, we report a widespread and dynamic remodeling of metabolism affecting central carbon metabolism, primary biosynthetic pathways, fermentation pathways, and secondary metabolism. This report serves as a unique hypothesis-generating resource for future studies on bacterial biofilm physiology. Outside the biofilm research area, this work should also prove relevant to any investigators interested in microbial physiology and metabolism. Biofilms are structured communities of tightly associated cells that constitute the predominant state of bacterial growth in natural and human-made environments. Although the core genetic circuitry that controls biofilm formation in model bacteria such as Bacillus subtilis has been well characterized, little is known about the role that metabolism plays in this complex developmental process. Here, we performed a time-resolved analysis of the metabolic changes associated with pellicle biofilm formation and development in B. subtilis by combining metabolomic, transcriptomic, and proteomic analyses. We report surprisingly widespread and dynamic remodeling of metabolism affecting central carbon metabolism, primary biosynthetic pathways, fermentation pathways, and secondary metabolism. Most of these metabolic alterations were hitherto unrecognized as biofilm associated. For example, we observed increased activity of the tricarboxylic acid (TCA) cycle during early biofilm growth, a shift from fatty acid biosynthesis to fatty acid degradation, reorganization of iron metabolism and transport, and a switch from acetate to acetoin fermentation. Close agreement between metabolomic, transcriptomic, and proteomic measurements indicated that remodeling of metabolism during biofilm development was largely controlled at the transcriptional level. Our results also provide insights into the transcription factors and regulatory networks involved in this complex metabolic remodeling. Following upon these results, we demonstrated that acetoin production via acetolactate synthase is essential for robust biofilm growth and has the dual role of conserving redox balance and maintaining extracellular pH. This report represents a comprehensive systems-level investigation of the metabolic remodeling occurring during B. subtilis biofilm development that will serve as a useful road map for future studies on biofilm physiology.
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18
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Santabarbara S, Casazza AP, Hastings G. Modelling electron transfer in photosystem I: limits and perspectives. PHYSIOLOGIA PLANTARUM 2019; 166:73-87. [PMID: 30847929 DOI: 10.1111/ppl.12959] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/05/2019] [Accepted: 03/05/2019] [Indexed: 06/09/2023]
Abstract
Uncovering the parameters underlying the electron transfer (ET) in photosynthetic reaction centres is of importance for understanding the molecular mechanisms underpinning their functionality. The reductive nature of most cofactors involved in photosynthetic ET makes the direct estimation of their properties difficult. Photosystem I (PSI) operates in a highly reducing regime, making the assessment of cofactor properties even more difficult. Kinetic modelling coupled to a non-adiabatic description of ET is a useful approach in overcoming this hindrance. Here we review the theory and modelling approaches that have been used in assessing parameters associated with ET reactions in PSI, with particular attention to ET reactions involving the phylloquinones and the iron-sulphur clusters. In most modelling studies, the goal is to estimate the driving force of ET, which is usually associated with the cofactor midpoint potentials. The driving force is sensitive to many factors, which define the ET rate, i.e. the reorganisation energy, the coupling with nuclear modes and the electronic matrix elements, which are explored and discussed here. The importance of an inclusive modelling of both forward and reverse ET processes is discussed and highlighted. It is shown that although estimates are indeed sensitive to the exact parameter sets employed in the modelling, a general consensus is still attained, pointing to a scenario where Δ G A 1 A → F X 0 / Δ G A 1 B → F X 0 is weakly endergonic/exergonic, respectively. It is emphasised that to further refine those estimates, it will require a joint effort between computational modelling and more wide-ranging experimental studies.
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Affiliation(s)
- Stefano Santabarbara
- Centre for Fundamental Research in Photosynthesis, 21029, Varese, Italy
- Photosynthesis Research Unit, Centro Studi sulla Biologia Cellulare e Molecolare delle Piante, 20133, Milan, Italy
| | - Anna Paola Casazza
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, 20133, Milan, Italy
| | - Gary Hastings
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA, 30303, USA
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19
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Pernil R, Schleiff E. Metalloproteins in the Biology of Heterocysts. Life (Basel) 2019; 9:E32. [PMID: 30987221 PMCID: PMC6616624 DOI: 10.3390/life9020032] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/18/2019] [Accepted: 03/28/2019] [Indexed: 12/15/2022] Open
Abstract
Cyanobacteria are photoautotrophic microorganisms present in almost all ecologically niches on Earth. They exist as single-cell or filamentous forms and the latter often contain specialized cells for N₂ fixation known as heterocysts. Heterocysts arise from photosynthetic active vegetative cells by multiple morphological and physiological rearrangements including the absence of O₂ evolution and CO₂ fixation. The key function of this cell type is carried out by the metalloprotein complex known as nitrogenase. Additionally, many other important processes in heterocysts also depend on metalloproteins. This leads to a high metal demand exceeding the one of other bacteria in content and concentration during heterocyst development and in mature heterocysts. This review provides an overview on the current knowledge of the transition metals and metalloproteins required by heterocysts in heterocyst-forming cyanobacteria. It discusses the molecular, physiological, and physicochemical properties of metalloproteins involved in N₂ fixation, H₂ metabolism, electron transport chains, oxidative stress management, storage, energy metabolism, and metabolic networks in the diazotrophic filament. This provides a detailed and comprehensive picture on the heterocyst demands for Fe, Cu, Mo, Ni, Mn, V, and Zn as cofactors for metalloproteins and highlights the importance of such metalloproteins for the biology of cyanobacterial heterocysts.
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Affiliation(s)
- Rafael Pernil
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany.
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Straβe 15, 60438 Frankfurt am Main, Germany.
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20
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Zhao F, Ruff A, Rögner M, Schuhmann W, Conzuelo F. Extended Operational Lifetime of a Photosystem-Based Bioelectrode. J Am Chem Soc 2019; 141:5102-5106. [PMID: 30888806 DOI: 10.1021/jacs.8b13869] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The development of bioelectrochemical assemblies for sustainable energy transformation constitutes an increasingly important field of research. Significant progress has been made in the development of semiartificial devices for conversion of light into electrical energy by integration of photosynthetic biomolecules on electrodes. However, sufficient long-term stability of such biophotoelectrodes has been compromised by reactive species generated under aerobic operation. Therefore, meeting the requirements of practical applications still remains unsolved. We present the operation of a photosystem I-based photocathode using an electron acceptor that enables photocurrent generation under anaerobic conditions as the basis for a biodevice with substantially improved stability. A continuous operation lifetime considerably superior to previous reports and at higher light intensities is paving the way toward the potential application of semiartificial energy conversion devices.
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Affiliation(s)
- Fangyuan Zhao
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry , Ruhr University Bochum , Universitätsstraße 150 , D-44780 Bochum , Germany
| | - Adrian Ruff
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry , Ruhr University Bochum , Universitätsstraße 150 , D-44780 Bochum , Germany
| | - Matthias Rögner
- Plant Biochemistry, Faculty of Biology and Biotechnology , Ruhr University Bochum , Universitätsstraße 150 , D-44780 Bochum , Germany
| | - Wolfgang Schuhmann
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry , Ruhr University Bochum , Universitätsstraße 150 , D-44780 Bochum , Germany
| | - Felipe Conzuelo
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry , Ruhr University Bochum , Universitätsstraße 150 , D-44780 Bochum , Germany
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21
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Utschig LM, Soltau SR, Mulfort KL, Niklas J, Poluektov OG. Z-scheme solar water splitting via self-assembly of photosystem I-catalyst hybrids in thylakoid membranes. Chem Sci 2018; 9:8504-8512. [PMID: 30568774 PMCID: PMC6256728 DOI: 10.1039/c8sc02841a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/20/2018] [Indexed: 01/01/2023] Open
Abstract
Nature's solar energy converters, the Photosystem I (PSI) and Photosystem II (PSII) reaction center proteins, flawlessly manage photon capture and conversion processes in plants, algae, and cyanobacteria to drive oxygenic water-splitting and carbon fixation. Herein, we utilize the native photosynthetic Z-scheme electron transport chain to drive hydrogen production from thylakoid membranes by directional electron transport to abiotic catalysts bound at the stromal end of PSI. Pt-nanoparticles readily self-assemble with PSI in spinach and cyanobacterial membranes as evidenced by light-driven H2 production in the presence of a mediating electron shuttle protein and the sacrificial electron donor sodium ascorbate. EPR characterization confirms placement of the Pt-nanoparticles on the acceptor end of PSI. In the absence of sacrificial reductant, H2 production at PSI occurs via coupling to light-induced PSII O2 evolution as confirmed by correlation of catalytic activity to the presence or absence of the PSII inhibitor DCMU. To create a more sustainable system, first-row transition metal molecular cobaloxime and nickel diphosphine catalysts were found to perform photocatalysis when bound in situ to cyanobacterial thylakoid membranes. Thus, the self-assembly of abiotic catalysts with photosynthetic membranes demonstrates a tenable method for accomplishing solar overall water splitting to generate H2, a renewable and clean fuel. This work benchmarks a significant advance toward improving photosynthetic efficiency for solar fuel production.
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Affiliation(s)
- Lisa M Utschig
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA .
| | - Sarah R Soltau
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA .
| | - Karen L Mulfort
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA .
| | - Jens Niklas
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA .
| | - Oleg G Poluektov
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA .
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22
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Structure of a PSI-LHCI-cyt b 6f supercomplex in Chlamydomonas reinhardtii promoting cyclic electron flow under anaerobic conditions. Proc Natl Acad Sci U S A 2018; 115:10517-10522. [PMID: 30254175 DOI: 10.1073/pnas.1809973115] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Photosynthetic linear electron flow (LEF) produces ATP and NADPH, while cyclic electron flow (CEF) exclusively drives photophosphorylation to supply extra ATP. The fine-tuning of linear and cyclic electron transport levels allows photosynthetic organisms to balance light energy absorption with cellular energy requirements under constantly changing light conditions. As LEF and CEF share many electron transfer components, a key question is how the same individual structural units contribute to these two different functional modes. Here, we report the structural identification of a photosystem I (PSI)-light harvesting complex I (LHCI)-cytochrome (cyt) b6f supercomplex isolated from the unicellular alga Chlamydomonas reinhardtii under anaerobic conditions, which induces CEF. This provides strong evidence for the model that enhanced CEF is induced by the formation of CEF supercomplexes, when stromal electron carriers are reduced, to generate additional ATP. The additional identification of PSI-LHCI-LHCII complexes is consistent with recent findings that both CEF enhancement and state transitions are triggered by similar conditions, but can occur independently from each other. Single molecule fluorescence correlation spectroscopy indicates a physical association between cyt b6f and fluorescent chlorophyll containing PSI-LHCI supercomplexes. Single particle analysis identified top-view projections of the corresponding PSI-LHCI-cyt b6f supercomplex. Based on molecular modeling and mass spectrometry analyses, we propose a model in which dissociation of LHCA2 and LHCA9 from PSI supports the formation of this CEF supercomplex. This is supported by the finding that a Δlhca2 knockout mutant has constitutively enhanced CEF.
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23
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Baymann F, Schoepp-Cothenet B, Duval S, Guiral M, Brugna M, Baffert C, Russell MJ, Nitschke W. On the Natural History of Flavin-Based Electron Bifurcation. Front Microbiol 2018; 9:1357. [PMID: 30018596 PMCID: PMC6037941 DOI: 10.3389/fmicb.2018.01357] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/05/2018] [Indexed: 11/23/2022] Open
Abstract
Electron bifurcation is here described as a special case of the continuum of electron transfer reactions accessible to two-electron redox compounds with redox cooperativity. We argue that electron bifurcation is foremost an electrochemical phenomenon based on (a) strongly inverted redox potentials of the individual redox transitions, (b) a high endergonicity of the first redox transition, and (c) an escapement-type mechanism rendering completion of the first electron transfer contingent on occurrence of the second one. This mechanism is proposed to govern both the traditional quinone-based and the newly discovered flavin-based versions of electron bifurcation. Conserved and variable aspects of the spatial arrangement of electron transfer partners in flavoenzymes are assayed by comparing the presently available 3D structures. A wide sample of flavoenzymes is analyzed with respect to conserved structural modules and three major structural groups are identified which serve as basic frames for the evolutionary construction of a plethora of flavin-containing redox enzymes. We argue that flavin-based and other types of electron bifurcation are of primordial importance to free energy conversion, the quintessential foundation of life, and discuss a plausible evolutionary ancestry of the mechanism.
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Affiliation(s)
- Frauke Baymann
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | | | - Simon Duval
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | - Marianne Guiral
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | - Myriam Brugna
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | - Carole Baffert
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
| | - Michael J. Russell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
| | - Wolfgang Nitschke
- CNRS, BIP, UMR 7281, IMM FR3479, Aix-Marseille University, Marseille, France
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24
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Kundu M, He TF, Lu Y, Wang L, Zhong D. Short-Range Electron Transfer in Reduced Flavodoxin: Ultrafast Nonequilibrium Dynamics Coupled with Protein Fluctuations. J Phys Chem Lett 2018; 9:2782-2790. [PMID: 29722985 PMCID: PMC7304529 DOI: 10.1021/acs.jpclett.8b00882] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Short-range electron transfer (ET) in proteins is an ultrafast process on the similar time scales as local protein-solvent fluctuation, and thus the two dynamics are coupled. Here we use semiquinone flavodoxin and systematically characterized the photoinduced redox cycle with 11 mutations of different aromatic electron donors (tryptophan and tyrosine) and local residues to change redox properties. We observed the forward and backward ET dynamics in a few picoseconds, strongly following a stretched behavior resulting from a coupling between local environment relaxations and these ET processes. We further observed the hot vibrational-state formation through charge recombination and the subsequent cooling dynamics also in a few picoseconds. Combined with the ET studies in oxidized flavodoxin, these results coherently reveal the evolution of the ET dynamics from single to stretched exponential behaviors and thus elucidate critical time scales for the coupling. The observed hot vibration-state formation is robust and should be considered in all photoinduced back ET processes in flavoproteins.
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25
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Marco P, Kozuleva M, Eilenberg H, Mazor Y, Gimeson P, Kanygin A, Redding K, Weiner I, Yacoby I. Binding of ferredoxin to algal photosystem I involves a single binding site and is composed of two thermodynamically distinct events. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:234-243. [DOI: 10.1016/j.bbabio.2018.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 01/07/2018] [Accepted: 01/08/2018] [Indexed: 10/18/2022]
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26
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Kapoor K, Cashman DJ, Nientimp L, Bruce BD, Baudry J. Binding Mechanisms of Electron Transport Proteins with Cyanobacterial Photosystem I: An Integrated Computational and Experimental Model. J Phys Chem B 2018; 122:1026-1036. [PMID: 29211957 DOI: 10.1021/acs.jpcb.7b08307] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The stromal domain (PsaC, D, and E) of photosystem I (PSI) in cyanobacteria accepts electrons from PsaA and PsaB of photosystem I (PSI). These electrons are then used in the reduction of transiently bound ferredoxin (Fd) or flavodoxin. Experimental X-ray and NMR structures are known for all of these protein partners separately, yet to date, there is no known experimental structure of the PSI/Fd complexes in the published literature. Computational models of Fd docked with the stromal domain of cyanobacterial PSI were assembled here starting from X-ray and NMR structures of PSI and Fd. Predicted models of specific regions of protein-protein interactions were built on the basis of energetic frustration, residue conservation and evolutionary importance, as well as from experimental site-directed mutagenesis and cross-linking studies. Microsecond time-scale molecular dynamics simulations of the PSI/Fd complexes suggest, rather than a single complex structure, the possible existence of multiple transient complexes of Fd bound to PSI.
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Affiliation(s)
- Karan Kapoor
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States.,UT/ORNL Center for Molecular Biophysics , Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Derek J Cashman
- Department of Chemistry, Tennessee Technological University , Box 5055, Cookeville, Tennessee 38505-0001, United States
| | - Luke Nientimp
- Department of Chemistry, Tennessee Technological University , Box 5055, Cookeville, Tennessee 38505-0001, United States
| | - Barry D Bruce
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Jerome Baudry
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States.,UT/ORNL Center for Molecular Biophysics , Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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27
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Cherepanov DA, Milanovsky GE, Petrova AA, Tikhonov AN, Semenov AY. Electron Transfer through the Acceptor Side of Photosystem I: Interaction with Exogenous Acceptors and Molecular Oxygen. BIOCHEMISTRY (MOSCOW) 2018; 82:1249-1268. [PMID: 29223152 DOI: 10.1134/s0006297917110037] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review considers the state-of-the-art on mechanisms and alternative pathways of electron transfer in photosynthetic electron transport chains of chloroplasts and cyanobacteria. The mechanisms of electron transport control between photosystems (PS) I and II and the Calvin-Benson cycle are considered. The redistribution of electron fluxes between the noncyclic, cyclic, and pseudocyclic pathways plays an important role in the regulation of photosynthesis. Mathematical modeling of light-induced electron transport processes is considered. Particular attention is given to the electron transfer reactions on the acceptor side of PS I and to interactions of PS I with exogenous acceptors, including molecular oxygen. A kinetic model of PS I and its interaction with exogenous electron acceptors has been developed. This model is based on experimental kinetics of charge recombination in isolated PS I. Kinetic and thermodynamic parameters of the electron transfer reactions in PS I are scrutinized. The free energies of electron transfer between quinone acceptors A1A/A1B in the symmetric redox cofactor branches of PS I and iron-sulfur clusters FX, FA, and FB have been estimated. The second-order rate constants of electron transfer from PS I to external acceptors have been determined. The data suggest that byproduct formation of superoxide radical in PS I due to the reduction of molecular oxygen in the A1 site (Mehler reaction) can exceed 0.3% of the total electron flux in PS I.
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Affiliation(s)
- D A Cherepanov
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119992, Russia.
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Gao J, Wang H, Yuan Q, Feng Y. Structure and Function of the Photosystem Supercomplexes. FRONTIERS IN PLANT SCIENCE 2018; 9:357. [PMID: 29616068 PMCID: PMC5869908 DOI: 10.3389/fpls.2018.00357] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/02/2018] [Indexed: 05/21/2023]
Abstract
Photosynthesis converts solar energy into chemical energy to sustain all life on earth by providing oxygen and food, and controlling the atmospheric carbon dioxide. During this process, the water-splitting and oxygen-evolving reaction is catalyzed by photosystem II (PSII), while photosystem I (PSI) generates the reducing power for the reduction of NADP+ to NADPH. Together with their peripheral light-harvesting complexes (LHCs), photosystems function as multisubunit supercomplexes located in the thylakoid membranes of cyanobacteria, algae, and plants. Recent advances in single-particle cryo-electron microscopy (cryoEM), X-ray free electron laser (XFEL) and other techniques have revealed unprecedented structural and catalytic details concerning the two supercomplexes. Several high-resolution structures of the complexes from plants were solved, and serial time-resolved crystallography and "radiation-damage-free" femtosecond XFEL also provided important insights into the mechanism of water oxidation. Here, we review these exciting advances in the studies of the photosystem supercomplexes with an emphasis on PSII-LHCII, propose presently unresolved problems in this field, and suggest potential tendencies for future studies.
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Affiliation(s)
- Jinlan Gao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Hao Wang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Qipeng Yuan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Yue Feng
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
- *Correspondence: Yue Feng, ;
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29
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Schreiber U. Redox changes of ferredoxin, P700, and plastocyanin measured simultaneously in intact leaves. PHOTOSYNTHESIS RESEARCH 2017; 134:343-360. [PMID: 28497192 PMCID: PMC5683063 DOI: 10.1007/s11120-017-0394-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 05/03/2017] [Indexed: 05/07/2023]
Abstract
Properties and performance of the recently introduced Dual/KLAS-NIR spectrophotometer for simultaneous measurements of ferredoxin (Fd), P700, and plastocyanin (PC) redox changes, together with whole leaf chlorophyll a (Chl) fluorescence (emission >760, 540 nm excitation) are outlined. Spectral information on in vivo Fd, P700, and PC in the near-infrared region (NIR, 780-1000 nm) is presented, on which the new approach is based. Examples of application focus on dark-light and light-dark transitions, where maximal redox changes of Fd occur. After dark-adaptation, Fd reduction induced by moderate light parallels the Kautsky effect of Chl fluorescence induction. Both signals are affected analogously by removal of O2. A rapid type of Fd reoxidation, observed after a short pulse of light before light activation of linear electron transport (LET), is more pronounced in C4 compared to C3 leaves and interpreted to reflect cyclic PS I (CET). Light activation of LET, as assessed via the rate of Fd reoxidation after short light pulses, occurs at very low intensities and is slowly reversed (half-time ca. 20 min). Illumination with strong far-red light (FR, 740 nm) reveals two fractions of PS I, PS I (LET), and PS I (CET), differing in the rates of Fd reoxidation upon FR-off and the apparent equilibrium constants between P700 and PC. Parallel information on oxidation of Fd and reduction of P700 plus PC proves essential for identification of CET. Comparison of maize (C4) with sunflower and ivy (C3) responses leads to the conclusion that segregation of two types of PS I may not only exist in C4 (mesophyll and bundle sheath cells), but also in C3 photosynthesis (grana margins plus end membranes and stroma lamellae).
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Affiliation(s)
- Ulrich Schreiber
- Julius-von-Sachs Institut für Biowissenschaften, Universität Würzburg, Julius-von-Sachs Platz 2, 97082, Würzburg, Germany.
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30
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Mignée C, Mutoh R, Krieger-Liszkay A, Kurisu G, Sétif P. Gallium ferredoxin as a tool to study the effects of ferredoxin binding to photosystem I without ferredoxin reduction. PHOTOSYNTHESIS RESEARCH 2017; 134:251-263. [PMID: 28205062 DOI: 10.1007/s11120-016-0332-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 12/27/2016] [Indexed: 06/06/2023]
Abstract
Reduction of ferredoxin by photosystem I (PSI) involves the [4Fe-4S] clusters FA and FB harbored by PsaC, with FB being the direct electron transfer partner of ferredoxin (Fd). Binding of the redox-inactive gallium ferredoxin to PSI was investigated by flash-absorption spectroscopy, studying both the P700+ decay and the reduction of the native iron Fd in the presence of FdGa. FdGa binding resulted in a faster recombination between P700+ and (FA, FB)-, a slower electron escape from (FA, FB)- to exogenous acceptors, and a decreased amount of intracomplex FdFe reduction, in accordance with competitive binding between FdFe and FdGa. [FdGa] titrations of these effects revealed that the dissociation constant for the PSI:FdGa complex is different whether (FA, FB) is oxidized or singly reduced. This difference in binding, together with the increase in the recombination rate, could both be attributed to a c. -30 mV shift of the midpoint potential of (FA, FB), considered as a single electron acceptor, due to FdGa binding. This effect of FdGa binding, which can be extrapolated to FdFe because of the highly similar structure and the identical charge of the two Fds, should help irreversibility of electron transfer within the PSI:Fd complex. The effect of Fd binding on the individual midpoint potentials of FA and FB is also discussed with respect to the possible consequences on intra-PSI electron transfer and on the escape process.
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Affiliation(s)
- Clara Mignée
- Institut de Biologie Intégrative de la Cellule (I2BC), IBITECS, CEA, CNRS, Univ. Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
| | - Risa Mutoh
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Anja Krieger-Liszkay
- Institut de Biologie Intégrative de la Cellule (I2BC), IBITECS, CEA, CNRS, Univ. Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Pierre Sétif
- Institut de Biologie Intégrative de la Cellule (I2BC), IBITECS, CEA, CNRS, Univ. Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France.
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31
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Milanovsky GE, Petrova AA, Cherepanov DA, Semenov AY. Kinetic modeling of electron transfer reactions in photosystem I complexes of various structures with substituted quinone acceptors. PHOTOSYNTHESIS RESEARCH 2017; 133:185-199. [PMID: 28352992 DOI: 10.1007/s11120-017-0366-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 03/01/2017] [Indexed: 05/09/2023]
Abstract
The reduction kinetics of the photo-oxidized primary electron donor P700 in photosystem I (PS I) complexes from cyanobacteria Synechocystis sp. PCC 6803 were analyzed within the kinetic model, which considers electron transfer (ET) reactions between P700, secondary quinone acceptor A1, iron-sulfur clusters and external electron donor and acceptors - methylviologen (MV), 2,3-dichloro-naphthoquinone (Cl2NQ) and oxygen. PS I complexes containing various quinones in the A1-binding site (phylloquinone PhQ, plastoquinone-9 PQ and Cl2NQ) as well as F X-core complexes, depleted of terminal iron-sulfur F A/F B clusters, were studied. The acceleration of charge recombination in F X-core complexes by PhQ/PQ substitution indicates that backward ET from the iron-sulfur clusters involves quinone in the A1-binding site. The kinetic parameters of ET reactions were obtained by global fitting of the P700+ reduction with the kinetic model. The free energy gap ΔG 0 between F X and F A/F B clusters was estimated as -130 meV. The driving force of ET from A1 to F X was determined as -50 and -220 meV for PhQ in the A and B cofactor branches, respectively. For PQ in A1A-site, this reaction was found to be endergonic (ΔG 0 = +75 meV). The interaction of PS I with external acceptors was quantitatively described in terms of Michaelis-Menten kinetics. The second-order rate constants of ET from F A/F B, F X and Cl2NQ in the A1-site of PS I to external acceptors were estimated. The side production of superoxide radical in the A1-site by oxygen reduction via the Mehler reaction might comprise ≥0.3% of the total electron flow in PS I.
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Affiliation(s)
- Georgy E Milanovsky
- A.N. Belozersky Institute of Physical-Chemical Biology, Moscow State University, Moscow, Russia
| | - Anastasia A Petrova
- A.N. Belozersky Institute of Physical-Chemical Biology, Moscow State University, Moscow, Russia
| | - Dmitry A Cherepanov
- A.N. Belozersky Institute of Physical-Chemical Biology, Moscow State University, Moscow, Russia.
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia.
| | - Alexey Yu Semenov
- A.N. Belozersky Institute of Physical-Chemical Biology, Moscow State University, Moscow, Russia.
- N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russia.
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32
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Inverted-region electron transfer as a mechanism for enhancing photosynthetic solar energy conversion efficiency. Proc Natl Acad Sci U S A 2017; 114:9267-9272. [PMID: 28814630 DOI: 10.1073/pnas.1704855114] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In all photosynthetic organisms, light energy is used to drive electrons from a donor chlorophyll species via a series of acceptors across a biological membrane. These light-induced electron-transfer processes display a remarkably high quantum efficiency, indicating a near-complete inhibition of unproductive charge recombination reactions. It has been suggested that unproductive charge recombination could be inhibited if the reaction occurs in the so-called inverted region. However, inverted-region electron transfer has never been demonstrated in any native photosynthetic system. Here we demonstrate that the unproductive charge recombination in native photosystem I photosynthetic reaction centers does occur in the inverted region, at both room and cryogenic temperatures. Computational modeling of light-induced electron-transfer processes in photosystem I demonstrate a marked decrease in photosynthetic quantum efficiency, from 98% to below 72%, if the unproductive charge recombination process does not occur in the inverted region. Inverted-region electron transfer is therefore demonstrated to be an important mechanism contributing to efficient solar energy conversion in photosystem I. Inverted-region electron transfer does not appear to be an important mechanism in other photosystems; it is likely because of the highly reducing nature of photosystem I, and the energetic requirements placed on the pigments to operate in such a regime, that the inverted-region electron transfer mechanism becomes important.
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33
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Sétif P, Mutoh R, Kurisu G. Dynamics and energetics of cyanobacterial photosystem I:ferredoxin complexes in different redox states. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:483-496. [DOI: 10.1016/j.bbabio.2017.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/24/2017] [Accepted: 04/12/2017] [Indexed: 10/19/2022]
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34
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El-Khouly ME, El-Mohsnawy E, Fukuzumi S. Solar energy conversion: From natural to artificial photosynthesis. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2017. [DOI: 10.1016/j.jphotochemrev.2017.02.001] [Citation(s) in RCA: 182] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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35
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Li Z, Yuan S, Jia H, Gao F, Zhou M, Yuan N, Wu P, Hu Q, Sun D, Luo H. Ectopic expression of a cyanobacterial flavodoxin in creeping bentgrass impacts plant development and confers broad abiotic stress tolerance. PLANT BIOTECHNOLOGY JOURNAL 2017; 15:433-446. [PMID: 27638479 PMCID: PMC5362689 DOI: 10.1111/pbi.12638] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/10/2016] [Accepted: 09/13/2016] [Indexed: 05/18/2023]
Abstract
Flavodoxin (Fld) plays a pivotal role in photosynthetic microorganisms as an alternative electron carrier flavoprotein under adverse environmental conditions. Cyanobacterial Fld has been demonstrated to be able to substitute ferredoxin of higher plants in most electron transfer processes under stressful conditions. We have explored the potential of Fld for use in improving plant stress response in creeping bentgrass (Agrostis stolonifera L.). Overexpression of Fld altered plant growth and development. Most significantly, transgenic plants exhibited drastically enhanced performance under oxidative, drought and heat stress as well as nitrogen (N) starvation, which was associated with higher water retention and cell membrane integrity than wild-type controls, modified expression of heat-shock protein genes, production of more reduced thioredoxin, elevated N accumulation and total chlorophyll content as well as up-regulated expression of nitrite reductase and N transporter genes. Further analysis revealed that the expression of other stress-related genes was also impacted in Fld-expressing transgenics. Our data establish a key role of Fld in modulating plant growth and development and plant response to multiple sources of adverse environmental conditions in crop species. This demonstrates the feasibility of manipulating Fld in crop species for genetic engineering of plant stress tolerance.
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Affiliation(s)
- Zhigang Li
- College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhanHubeiChina
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Shuangrong Yuan
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Haiyan Jia
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
- The Applied Plant Genomics Laboratory of Crop Genomics and Bioinformatics Centreand National Key Laboratory of Crop Genetics and Germplasm EnhancementNanjing Agricultural UniversityNanjingJiangsuChina
| | - Fangyuan Gao
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
- Crop Research InstituteSichuan Academy of Agricultural SciencesChengduSichuanChina
| | - Man Zhou
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Ning Yuan
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Peipei Wu
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Qian Hu
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Dongfa Sun
- College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhanHubeiChina
| | - Hong Luo
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
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36
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Atkinson JT, Campbell I, Bennett GN, Silberg JJ. Cellular Assays for Ferredoxins: A Strategy for Understanding Electron Flow through Protein Carriers That Link Metabolic Pathways. Biochemistry 2016; 55:7047-7064. [DOI: 10.1021/acs.biochem.6b00831] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua T. Atkinson
- Systems,
Synthetic, and Physical Biology Graduate Program, Rice University, MS-180, 6100 Main Street, Houston, Texas 77005, United States
| | - Ian Campbell
- Biochemistry
and Cell Biology Graduate Program, Rice University, MS-140, 6100
Main Street, Houston, Texas 77005, United States
| | - George N. Bennett
- Department
of Biosciences, Rice University, MS-140, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Chemical and Biomolecular Engineering, Rice University, MS-362,
6100 Main Street, Houston, Texas 77005, United States
| | - Jonathan J. Silberg
- Department
of Biosciences, Rice University, MS-140, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Bioengineering, Rice University, MS-142, 6100 Main Street, Houston, Texas 77005, United States
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37
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Seo D, Kitashima M, Sakurai T, Inoue K. Kinetics of NADP +/NADPH reduction-oxidation catalyzed by the ferredoxin-NAD(P) + reductase from the green sulfur bacterium Chlorobaculum tepidum. PHOTOSYNTHESIS RESEARCH 2016; 130:479-489. [PMID: 27341807 DOI: 10.1007/s11120-016-0285-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/13/2016] [Indexed: 06/06/2023]
Abstract
Ferredoxin-NAD(P)+ oxidoreductase (FNR, [EC 1.18.1.2], [EC 1.18.1.3]) from the green sulfur bacterium Chlorobaculum tepidum (CtFNR) is a homodimeric flavoprotein with significant structural homology to bacterial NADPH-thioredoxin reductases. CtFNR homologs have been found in many bacteria, but only in green sulfur bacteria among photoautotrophs. In this work, we examined the reactions of CtFNR with NADP+, NADPH, and (4S-2H)-NADPD by stopped-flow spectrophotometry. Mixing CtFNRox with NADPH yielded a rapid decrease of the absorbance in flavin band I centered at 460 nm within 1 ms, and then the absorbance further decreased gradually. The magnitude of the decrease increased with increasing NADPH concentration, but even with ~50-fold molar excess NADPH, the absorbance change was only ~45 % of that expected for fully reduced protein. The absorbance in the charge transfer (CT) band centered around 600 nm increased rapidly within 1 ms, then slowly decreased to about 70 % of the maximum. When CtFNRred was mixed with excess NADP+, the absorbance in the flavin band I increased to about 70 % of that of CtFNRox with an apparent rate of ~4 s-1, whereas almost no absorption changes were observed in the CT band. Obtained data suggest that the reaction between CtFNR and NADP+/NADPH is reversible, in accordance with its physiological function.
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Affiliation(s)
- Daisuke Seo
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa, 920-1192, Japan.
| | - Masaharu Kitashima
- Department of Biological Sciences, Kanagawa University, Tsuchiya, Hiratsuka, Kanagawa, 259-1293, Japan
- Research Institute for Integrated Science, Kanagawa University, Tsuchiya, Hiratsuka, Kanagawa, 259-1293, Japan
| | - Takeshi Sakurai
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa, 920-1192, Japan
| | - Kazuhito Inoue
- Department of Biological Sciences, Kanagawa University, Tsuchiya, Hiratsuka, Kanagawa, 259-1293, Japan
- Research Institute for Integrated Science, Kanagawa University, Tsuchiya, Hiratsuka, Kanagawa, 259-1293, Japan
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38
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Pochekailov S, Black RR, Chavali VP, Khakhar A, Seelig G. A Fluorescent Readout for the Oxidation State of Electron Transporting Proteins in Cell Free Settings. ACS Synth Biol 2016; 5:662-71. [PMID: 27049848 DOI: 10.1021/acssynbio.5b00274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Pathways involving sequential electron transfer between multiple proteins are ubiquitous in nature. Here, we demonstrate a new class of fluorescent protein-based reporters for monitoring electron transport through such multistage cascades, specifically those involving ferredoxin-like electron transporters. We created protein fusions between mammalian Adrenodoxin (Adx) and plant Ferredoxin (Fdx) with fluorescent proteins of different colors and found that the fluorescence of such fusions is highly sensitive to the redox state of the electron transporter. The increase in fluorescence from the oxidized to the reduced state was inversely proportional to the linker length between the fusion partners. We first used our approach to quantitatively characterize electron transfer from NADPH through Adrenodoxin Reductase (AdR) to Adrenodoxin (Adx). Our data allowed us to build a detailed mathematical model of this mitochondrial electron transfer chain and validate previously proposed mechanisms. Then, we showed that an Adx-GFP fusion could serve as a sensor for the activity of bacterial Type I Cytochrome P450s (CYPs), a very large class of enzymes with important roles in biotechnology. We further showed that fluorescence of a direct fusion between CYP and GFP was sensitive to CYP activity, suggesting that our approach is applicable to an even broader class of proteins, which undergo a redox state change during their work cycle.
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Affiliation(s)
- Sergii Pochekailov
- Department
of Electrical Engineering, University of Washington, Seattle, 98195 Washington, United States
| | - Rebecca R. Black
- Department
of Electrical Engineering, University of Washington, Seattle, 98195 Washington, United States
| | - Venkata Pramod Chavali
- Department
of Electrical Engineering, University of Washington, Seattle, 98195 Washington, United States
| | - Arjun Khakhar
- Department
of Electrical Engineering, University of Washington, Seattle, 98195 Washington, United States
| | - Georg Seelig
- Department
of Electrical Engineering, University of Washington, Seattle, 98195 Washington, United States
- Department
of Computer Science and Engineering, University of Washington, Seattle, 98195 Washington, United States
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39
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Mustila H, Paananen P, Battchikova N, Santana-Sánchez A, Muth-Pawlak D, Hagemann M, Aro EM, Allahverdiyeva Y. The Flavodiiron Protein Flv3 Functions as a Homo-Oligomer During Stress Acclimation and is Distinct from the Flv1/Flv3 Hetero-Oligomer Specific to the O2 Photoreduction Pathway. PLANT & CELL PHYSIOLOGY 2016; 57:1468-1483. [PMID: 26936793 PMCID: PMC4937785 DOI: 10.1093/pcp/pcw047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 02/23/2016] [Indexed: 05/06/2023]
Abstract
The flavodiiron proteins (FDPs) Flv1 and Flv3 in cyanobacteria function in photoreduction of O2 to H2O, without concomitant formation of reactive oxygen species, known as the Mehler-like reaction. Both Flv1 and Flv3 are essential for growth under fluctuating light (FL) intensities, providing protection for PSI. Here we compared the global transcript profiles of the wild type (WT), Δflv1 and Δflv1/Δflv3 grown under constant light (GL) and FL. In the WT, FL induced the largest down-regulation in transcripts involved in carbon-concentrating mechanisms (CCMs), while those of the nitrogen assimilation pathways increased as compared with GL. Already under GL the Δflv1/Δflv3 double mutant demonstrated a partial down-regulation of transcripts for CCM and nitrogen metabolism, while in FL conditions the transcripts for nitrogen assimilation were strongly down-regulated. Many alterations were specific only for Δflv1/Δflv3, and not detected in Δflv1, suggesting that certain transcripts are affected primarily because of the lack of flv3 By constructing the strains overproducing solely either Flv1 or Flv3, we demonstrate that the homo-oligomers of these proteins also function in acclimation of cells to FL, by catalyzing reactions with as yet unidentified components, while the presence of both Flv1 and Flv3 is a prerequisite for the Mehler-like reaction and thus the electron transfer to O2 Considering the low expression of flv1, it is unlikely that the Flv1 homo-oligomer is present in the WT.
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Affiliation(s)
- Henna Mustila
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Pasi Paananen
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Natalia Battchikova
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Anita Santana-Sánchez
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Dorota Muth-Pawlak
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Martin Hagemann
- Institut Biowissenschaften, Pflanzenphysiologie, Universität Rostock, Albert-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Eva-Mari Aro
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Yagut Allahverdiyeva
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
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40
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Kondo T, Matsuoka M, Azai C, Itoh S, Oh-oka H. Orientations of Iron–Sulfur Clusters FA and FB in the Homodimeric Type-I Photosynthetic Reaction Center of Heliobacterium modesticaldum. J Phys Chem B 2016; 120:4204-12. [DOI: 10.1021/acs.jpcb.6b01112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Toru Kondo
- Division
of Material Science (Physics), Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8602, Japan
| | - Masahiro Matsuoka
- Department
of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
| | - Chihiro Azai
- Department
of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
| | - Shigeru Itoh
- Center
for Gene Research, Nagoya University, Furocho, Chikusa, Nagoya 464-8602, Japan
| | - Hirozo Oh-oka
- Department
of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
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41
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Klughammer C, Schreiber U. Deconvolution of ferredoxin, plastocyanin, and P700 transmittance changes in intact leaves with a new type of kinetic LED array spectrophotometer. PHOTOSYNTHESIS RESEARCH 2016; 128:195-214. [PMID: 26837213 PMCID: PMC4826414 DOI: 10.1007/s11120-016-0219-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/11/2016] [Indexed: 05/19/2023]
Abstract
A newly developed compact measuring system for assessment of transmittance changes in the near-infrared spectral region is described; it allows deconvolution of redox changes due to ferredoxin (Fd), P700, and plastocyanin (PC) in intact leaves. In addition, it can also simultaneously measure chlorophyll fluorescence. The major opto-electronic components as well as the principles of data acquisition and signal deconvolution are outlined. Four original pulse-modulated dual-wavelength difference signals are measured (785-840 nm, 810-870 nm, 870-970 nm, and 795-970 nm). Deconvolution is based on specific spectral information presented graphically in the form of 'Differential Model Plots' (DMP) of Fd, P700, and PC that are derived empirically from selective changes of these three components under appropriately chosen physiological conditions. Whereas information on maximal changes of Fd is obtained upon illumination after dark-acclimation, maximal changes of P700 and PC can be readily induced by saturating light pulses in the presence of far-red light. Using the information of DMP and maximal changes, the new measuring system enables on-line deconvolution of Fd, P700, and PC. The performance of the new device is demonstrated by some examples of practical applications, including fast measurements of flash relaxation kinetics and of the Fd, P700, and PC changes paralleling the polyphasic fluorescence rise upon application of a 300-ms pulse of saturating light.
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Affiliation(s)
- Christof Klughammer
- Julius-von-Sachs Institut für Biowissenschaften, Universität Würzburg, Julius-von-Sachs Platz 2, 97082, Würzburg, Germany
| | - Ulrich Schreiber
- Julius-von-Sachs Institut für Biowissenschaften, Universität Würzburg, Julius-von-Sachs Platz 2, 97082, Würzburg, Germany.
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Klughammer C, Schreiber U. Deconvolution of ferredoxin, plastocyanin, and P700 transmittance changes in intact leaves with a new type of kinetic LED array spectrophotometer. PHOTOSYNTHESIS RESEARCH 2016. [PMID: 26837213 DOI: 10.1007/s11120-016-0219-210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A newly developed compact measuring system for assessment of transmittance changes in the near-infrared spectral region is described; it allows deconvolution of redox changes due to ferredoxin (Fd), P700, and plastocyanin (PC) in intact leaves. In addition, it can also simultaneously measure chlorophyll fluorescence. The major opto-electronic components as well as the principles of data acquisition and signal deconvolution are outlined. Four original pulse-modulated dual-wavelength difference signals are measured (785-840 nm, 810-870 nm, 870-970 nm, and 795-970 nm). Deconvolution is based on specific spectral information presented graphically in the form of 'Differential Model Plots' (DMP) of Fd, P700, and PC that are derived empirically from selective changes of these three components under appropriately chosen physiological conditions. Whereas information on maximal changes of Fd is obtained upon illumination after dark-acclimation, maximal changes of P700 and PC can be readily induced by saturating light pulses in the presence of far-red light. Using the information of DMP and maximal changes, the new measuring system enables on-line deconvolution of Fd, P700, and PC. The performance of the new device is demonstrated by some examples of practical applications, including fast measurements of flash relaxation kinetics and of the Fd, P700, and PC changes paralleling the polyphasic fluorescence rise upon application of a 300-ms pulse of saturating light.
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Affiliation(s)
- Christof Klughammer
- Julius-von-Sachs Institut für Biowissenschaften, Universität Würzburg, Julius-von-Sachs Platz 2, 97082, Würzburg, Germany
| | - Ulrich Schreiber
- Julius-von-Sachs Institut für Biowissenschaften, Universität Würzburg, Julius-von-Sachs Platz 2, 97082, Würzburg, Germany.
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43
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Boehm M, Alahuhta M, Mulder DW, Peden EA, Long H, Brunecky R, Lunin VV, King PW, Ghirardi ML, Dubini A. Crystal structure and biochemical characterization of Chlamydomonas FDX2 reveal two residues that, when mutated, partially confer FDX2 the redox potential and catalytic properties of FDX1. PHOTOSYNTHESIS RESEARCH 2016; 128:45-57. [PMID: 26526668 PMCID: PMC4791469 DOI: 10.1007/s11120-015-0198-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 10/14/2015] [Indexed: 05/25/2023]
Abstract
The green alga Chlamydomonas reinhardtii contains six plastidic [2Fe2S]-cluster ferredoxins (FDXs), with FDX1 as the predominant isoform under photoautotrophic growth. FDX2 is highly similar to FDX1 and has been shown to interact with specific enzymes (such as nitrite reductase), as well as to share interactors with FDX1, such as the hydrogenases (HYDA), ferredoxin:NAD(P) reductase I (FNR1), and pyruvate:ferredoxin oxidoreductase (PFR1), albeit performing at low catalytic rates. Here we report the FDX2 crystal structure solved at 1.18 Å resolution. Based on differences between the Chlorella fusca FDX1 and C. reinhardtii FDX2 structures, we generated and purified point-mutated versions of the FDX2 protein and assayed them in vitro for their ability to catalyze hydrogen and NADPH photo-production. The data show that structural differences at two amino acid positions contribute to functional differences between FDX1 and FDX2, suggesting that FDX2 might have evolved from FDX1 toward a different physiological role in the cell. Moreover, we demonstrate that the mutations affect both the midpoint potentials of the FDX and kinetics of the FNR reaction, possibly due to altered binding between FDX and FNR. An effect on H2 photo-production rates was also observed, although the kinetics of the reaction were not further characterized.
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Affiliation(s)
- Marko Boehm
- Biosciences Center, National Renewable Energy Laboratory, Mail Stop: 3313, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | - Markus Alahuhta
- Biosciences Center, National Renewable Energy Laboratory, Mail Stop: 3313, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Mail Stop: 3313, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | - Erin A Peden
- Biosciences Center, National Renewable Energy Laboratory, Mail Stop: 3313, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | - Hai Long
- Computational Science Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | - Roman Brunecky
- Biosciences Center, National Renewable Energy Laboratory, Mail Stop: 3313, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | - Vladimir V Lunin
- Biosciences Center, National Renewable Energy Laboratory, Mail Stop: 3313, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Mail Stop: 3313, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | - Maria L Ghirardi
- Biosciences Center, National Renewable Energy Laboratory, Mail Stop: 3313, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | - Alexandra Dubini
- Biosciences Center, National Renewable Energy Laboratory, Mail Stop: 3313, 15013 Denver West Parkway, Golden, CO, 80401, USA.
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González A, Sevilla E, Bes MT, Peleato ML, Fillat MF. Pivotal Role of Iron in the Regulation of Cyanobacterial Electron Transport. Adv Microb Physiol 2016; 68:169-217. [PMID: 27134024 DOI: 10.1016/bs.ampbs.2016.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron-containing metalloproteins are the main cornerstones for efficient electron transport in biological systems. The abundance and diversity of iron-dependent proteins in cyanobacteria makes those organisms highly dependent of this micronutrient. To cope with iron imbalance, cyanobacteria have developed a survey of adaptation strategies that are strongly related to the regulation of photosynthesis, nitrogen metabolism and other central electron transfer pathways. Furthermore, either in its ferrous form or as a component of the haem group, iron plays a crucial role as regulatory signalling molecule that directly or indirectly modulates the composition and efficiency of cyanobacterial redox reactions. We present here the major mechanism used by cyanobacteria to couple iron homeostasis to the regulation of electron transport, making special emphasis in processes specific in those organisms.
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Affiliation(s)
| | - E Sevilla
- University of Zaragoza, Zaragoza, Spain
| | - M T Bes
- University of Zaragoza, Zaragoza, Spain
| | | | - M F Fillat
- University of Zaragoza, Zaragoza, Spain.
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Kandemir B, Chakraborty S, Guo Y, Bren KL. Semisynthetic and Biomolecular Hydrogen Evolution Catalysts. Inorg Chem 2015; 55:467-77. [DOI: 10.1021/acs.inorgchem.5b02054] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Banu Kandemir
- Department of Chemistry, University of Rochester, Rochester New York 14627-0216, United States
| | - Saikat Chakraborty
- Department of Chemistry, University of Rochester, Rochester New York 14627-0216, United States
| | - Yixing Guo
- Department of Chemistry, University of Rochester, Rochester New York 14627-0216, United States
| | - Kara L. Bren
- Department of Chemistry, University of Rochester, Rochester New York 14627-0216, United States
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Ishara Silva K, Jagannathan B, Golbeck JH, Lakshmi KV. Elucidating the design principles of photosynthetic electron-transfer proteins by site-directed spin labeling EPR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:548-556. [PMID: 26334844 DOI: 10.1016/j.bbabio.2015.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 08/20/2015] [Indexed: 10/23/2022]
Abstract
Site-directed spin labeling electron paramagnetic resonance (SDSL EPR) spectroscopy is a powerful tool to determine solvent accessibility, side-chain dynamics, and inter-spin distances at specific sites in biological macromolecules. This information provides important insights into the structure and dynamics of both natural and designed proteins and protein complexes. Here, we discuss the application of SDSL EPR spectroscopy in probing the charge-transfer cofactors in photosynthetic reaction centers (RC) such as photosystem I (PSI) and the bacterial reaction center (bRC). Photosynthetic RCs are large multi-subunit proteins (molecular weight≥300 kDa) that perform light-driven charge transfer reactions in photosynthesis. These reactions are carried out by cofactors that are paramagnetic in one of their oxidation states. This renders the RCs unsuitable for conventional nuclear magnetic resonance spectroscopy investigations. However, the presence of native paramagnetic centers and the ability to covalently attach site-directed spin labels in RCs makes them ideally suited for the application of SDSL EPR spectroscopy. The paramagnetic centers serve as probes of conformational changes, dynamics of subunit assembly, and the relative motion of cofactors and peptide subunits. In this review, we describe novel applications of SDSL EPR spectroscopy for elucidating the effects of local structure and dynamics on the electron-transfer cofactors of photosynthetic RCs. Because SDSL EPR Spectroscopy is uniquely suited to provide dynamic information on protein motion, it is a particularly useful method in the engineering and analysis of designed electron transfer proteins and protein networks. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson.
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Affiliation(s)
- K Ishara Silva
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180; The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Bharat Jagannathan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802; Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802; Department of Chemistry, The Pennsylvania State University, University Park, PA 16802.
| | - K V Lakshmi
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180; The Baruch '60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180.
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Cashman DJ, Zhu T, Simmerman RF, Scott C, Bruce BD, Baudry J. Molecular interactions between photosystem I and ferredoxin: an integrated energy frustration and experimental model. J Mol Recognit 2015; 27:597-608. [PMID: 25178855 DOI: 10.1002/jmr.2384] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 03/21/2014] [Accepted: 04/18/2014] [Indexed: 11/10/2022]
Abstract
The stromal domain (PsaC, PsaD, and PsaE) of photosystem I (PSI) reduces transiently bound ferredoxin (Fd) or flavodoxin. Experimental structures exist for all of these protein partners individually, but no experimental structure of the PSI/Fd or PSI/flavodoxin complexes is presently available. Molecular models of Fd docked onto the stromal domain of the cyanobacterial PSI site are constructed here utilizing X-ray and NMR structures of PSI and Fd, respectively. Predictions of potential protein-protein interaction regions are based on experimental site-directed mutagenesis and cross-linking studies to guide rigid body docking calculations of Fd into PSI, complemented by energy landscape theory to bring together regions of high energetic frustration on each of the interacting proteins. The results identify two regions of high localized frustration on the surface of Fd that contain negatively charged Asp and Glu residues. This study predicts that these regions interact predominantly with regions of high localized frustration on the PsaC, PsaD, and PsaE chains of PSI, which include several residues predicted by previous experimental studies.
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Affiliation(s)
- Derek J Cashman
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA; UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, University of Tennessee, Oak Ridge, TN, 37831, USA
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Fukuzumi S. Artificial photosynthetic systems for production of hydrogen. Curr Opin Chem Biol 2015; 25:18-26. [DOI: 10.1016/j.cbpa.2014.12.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 11/29/2014] [Accepted: 12/02/2014] [Indexed: 11/28/2022]
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Electron-transfer kinetics in cyanobacterial cells: methyl viologen is a poor inhibitor of linear electron flow. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:212-222. [PMID: 25448535 DOI: 10.1016/j.bbabio.2014.10.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 10/24/2014] [Accepted: 10/28/2014] [Indexed: 01/13/2023]
Abstract
The inhibitor methyl viologen (MV) has been widely used in photosynthesis to study oxidative stress. Its effects on electron transfer kinetics in Synechocystis sp. PCC6803 cells were studied to characterize its electron-accepting properties. For the first hundreds of flashes following MV addition at submillimolar concentrations, the kinetics of NADPH formation were hardly modified (less than 15% decrease in signal amplitude) with a significant signal decrease only observed after more flashes or continuous illumination. The dependence of the P700 photooxidation kinetics on the MV concentration exhibited a saturation effect at 0.3 mM MV, a concentration which inhibits the recombination reactions in photosystem I. The kinetics of NADPH formation and decay under continuous light with MV at 0.3 mM showed that MV induces the oxidation of the NADP pool in darkness and that the yield of linear electron transfer decreased by only 50% after 1.5-2 photosystem-I turnovers. The unexpectedly poor efficiency of MV in inhibiting NADPH formation was corroborated by in vitro flash-induced absorption experiments with purified photosystem-I, ferredoxin and ferredoxin-NADP(+)-oxidoreductase. These experiments showed that the second-order rate constants of MV reduction are 20 to 40-fold smaller than the competing rate constants involved in reduction of ferredoxin and ferredoxin-NADP(+)-oxidoreductase. The present study shows that MV, which accepts electrons in vivo both at the level of photosystem-I and ferredoxin, can be used at submillimolar concentrations to inhibit recombination reactions in photosystem-I with only a moderate decrease in the efficiency of fast reactions involved in linear electron transfer and possibly cyclic electron transfer.
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Pierella Karlusich JJ, Lodeyro AF, Carrillo N. The long goodbye: the rise and fall of flavodoxin during plant evolution. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5161-78. [PMID: 25009172 PMCID: PMC4400536 DOI: 10.1093/jxb/eru273] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 05/27/2014] [Accepted: 05/28/2014] [Indexed: 05/18/2023]
Abstract
Ferredoxins are electron shuttles harbouring iron-sulfur clusters that connect multiple oxido-reductive pathways in organisms displaying different lifestyles. Some prokaryotes and algae express an isofunctional electron carrier, flavodoxin, which contains flavin mononucleotide as cofactor. Both proteins evolved in the anaerobic environment preceding the appearance of oxygenic photosynthesis. The advent of an oxygen-rich atmosphere proved detrimental to ferredoxin owing to iron limitation and oxidative damage to the iron-sulfur cluster, and many microorganisms induced flavodoxin expression to replace ferredoxin under stress conditions. Paradoxically, ferredoxin was maintained throughout the tree of life, whereas flavodoxin is absent from plants and animals. Of note is that flavodoxin expression in transgenic plants results in increased tolerance to multiple stresses and iron deficit, through mechanisms similar to those operating in microorganisms. Then, the question remains open as to why a trait that still confers plants such obvious adaptive benefits was not retained. We compare herein the properties of ferredoxin and flavodoxin, and their contrasting modes of expression in response to different environmental stimuli. Phylogenetic analyses suggest that the flavodoxin gene was already absent in the algal lineages immediately preceding land plants. Geographical distribution of phototrophs shows a bias against flavodoxin-containing organisms in iron-rich coastal/freshwater habitats. Based on these observations, we propose that plants evolved from freshwater macroalgae that already lacked flavodoxin because they thrived in an iron-rich habitat with no need to back up ferredoxin functions and therefore no selective pressure to keep the flavodoxin gene. Conversely, ferredoxin retention in the plant lineage is probably related to its higher efficiency as an electron carrier, compared with flavodoxin. Several lines of evidence supporting these contentions are presented and discussed.
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Affiliation(s)
- Juan J Pierella Karlusich
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Anabella F Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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