1
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Iyanagi T. Roles of Ferredoxin-NADP + Oxidoreductase and Flavodoxin in NAD(P)H-Dependent Electron Transfer Systems. Antioxidants (Basel) 2022; 11:2143. [PMID: 36358515 PMCID: PMC9687028 DOI: 10.3390/antiox11112143] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 07/21/2023] Open
Abstract
Distinct isoforms of FAD-containing ferredoxin-NADP+ oxidoreductase (FNR) and ferredoxin (Fd) are involved in photosynthetic and non-photosynthetic electron transfer systems. The FNR (FAD)-Fd [2Fe-2S] redox pair complex switches between one- and two-electron transfer reactions in steps involving FAD semiquinone intermediates. In cyanobacteria and some algae, one-electron carrier Fd serves as a substitute for low-potential FMN-containing flavodoxin (Fld) during growth under low-iron conditions. This complex evolves into the covalent FNR (FAD)-Fld (FMN) pair, which participates in a wide variety of NAD(P)H-dependent metabolic pathways as an electron donor, including bacterial sulfite reductase, cytochrome P450 BM3, plant or mammalian cytochrome P450 reductase and nitric oxide synthase isoforms. These electron transfer systems share the conserved Ser-Glu/Asp pair in the active site of the FAD module. In addition to physiological electron acceptors, the NAD(P)H-dependent diflavin reductase family catalyzes a one-electron reduction of artificial electron acceptors such as quinone-containing anticancer drugs. Conversely, NAD(P)H: quinone oxidoreductase (NQO1), which shares a Fld-like active site, functions as a typical two-electron transfer antioxidant enzyme, and the NQO1 and UDP-glucuronosyltransfease/sulfotransferase pairs function as an antioxidant detoxification system. In this review, the roles of the plant FNR-Fd and FNR-Fld complex pairs were compared to those of the diflavin reductase (FAD-FMN) family. In the final section, evolutionary aspects of NAD(P)H-dependent multi-domain electron transfer systems are discussed.
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Affiliation(s)
- Takashi Iyanagi
- Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Akoh 678-1297, Hyogo, Japan
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2
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Thioredoxin Reductase-Type Ferredoxin: NADP+ Oxidoreductase of Rhodopseudomonas palustris: Potentiometric Characteristics and Reactions with Nonphysiological Oxidants. Antioxidants (Basel) 2022; 11:antiox11051000. [PMID: 35624864 PMCID: PMC9137726 DOI: 10.3390/antiox11051000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/15/2022] [Accepted: 05/17/2022] [Indexed: 11/17/2022] Open
Abstract
Rhodopseudomonas palustris ferredoxin:NADP+ oxidoreductase (RpFNR) belongs to a novel group of thioredoxin reductase-type FNRs with partly characterized redox properties. Based on the reactions of RpFNR with the 3-acetylpyridine adenine dinucleotide phosphate redox couple, we estimated the two-electron reduction midpoint potential of the FAD cofactor to be −0.285 V. 5-Deaza-FMN-sensitized photoreduction revealed −0.017 V separation of the redox potentials between the first and second electron transfer events. We examined the mechanism of oxidation of RpFNR by several different groups of nonphysiological electron acceptors. The kcat/Km values of quinones and aromatic N-oxides toward RpFNR increase with their single-electron reduction midpoint potential. The lower reactivity, mirroring their lower electron self-exchange rate, is also seen to have a similar trend for nitroaromatic compounds. A mixed single- and two-electron reduction was characteristic of quinones, with single-electron reduction accounting for 54% of the electron flux, whereas nitroaromatics were reduced exclusively via single-electron reduction. It is highly possible that the FADH· to FAD oxidation reaction is the rate-limiting step during the reoxidation of reduced FAD. The calculated electron transfer distances in the reaction with quinones and nitroaromatics were close to those of Anabaena and Plasmodium falciparum FNRs, thus demonstrating their similar “intrinsic” reactivity.
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3
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Anaerobic Stopped-Flow Spectrophotometry with Photodiode Array Detection in the Presteady State: An Application to Elucidate Oxidoreduction Mechanisms in Flavoproteins. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2280:135-155. [PMID: 33751433 DOI: 10.1007/978-1-0716-1286-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Anaerobic stopped-flow (SF) spectrophotometry is a powerful biophysical tool that allows a complete kinetic characterization of protein interactions with other molecules when they are in different redox states, as well as of the redox processes consequence of such interactions. Differences in the absorption spectroscopic properties of oxidized, semiquinone and hydroquinone states of flavoproteins, as well as the appearance of transient spectroscopic features produced by the flavin cofactor during substrate binding and electron transfer processes, have made SF a suitable technique for kinetically dissecting their mechanisms of reaction. In addition, SF coupled to photodiode array detection, enables kinetic data collection in a wavelength range. When such type of data are available for a flavoprotein reaction, they allow for obtaining detailed information of individual reaction steps, including intermolecular dissociation constants as well as electron transfer rate constants. Methodologies for the mechanistic characterization of flavoproteins involved in redox processes by SF spectrophotometry are described in this chapter.
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4
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Megarity CF, Siritanaratkul B, Herold RA, Morello G, Armstrong FA. Electron flow between the worlds of Marcus and Warburg. J Chem Phys 2021; 153:225101. [PMID: 33317312 DOI: 10.1063/5.0024701] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Living organisms are characterized by the ability to process energy (all release heat). Redox reactions play a central role in biology, from energy transduction (photosynthesis, respiratory chains) to highly selective catalyzed transformations of complex molecules. Distance and scale are important: electrons transfer on a 1 nm scale, hydrogen nuclei transfer between molecules on a 0.1 nm scale, and extended catalytic processes (cascades) operate most efficiently when the different enzymes are under nanoconfinement (10 nm-100 nm scale). Dynamic electrochemistry experiments (defined broadly within the term "protein film electrochemistry," PFE) reveal details that are usually hidden in conventional kinetic experiments. In PFE, the enzyme is attached to an electrode, often in an innovative way, and electron-transfer reactions, individual or within steady-state catalytic flow, can be analyzed in terms of precise potentials, proton coupling, cooperativity, driving-force dependence of rates, and reversibility (a mark of efficiency). The electrochemical experiments reveal subtle factors that would have played an essential role in molecular evolution. This article describes how PFE is used to visualize and analyze different aspects of biological redox chemistry, from long-range directional electron transfer to electron/hydride (NADPH) interconversion by a flavoenzyme and finally to NADPH recycling in a nanoconfined enzyme cascade.
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Affiliation(s)
- Clare F Megarity
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
| | | | - Ryan A Herold
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
| | - Giorgio Morello
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
| | - Fraser A Armstrong
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
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5
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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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6
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Zhan H, Song L, Kamran A, Han F, Li B, Zhou Z, Liu T, Shen L, Li Y, Wang F, Yang J. Comprehensive Proteomic Analysis of Lysine Ubiquitination in Seedling Leaves of Nicotiana tabacum. ACS OMEGA 2020; 5:20122-20133. [PMID: 32832766 PMCID: PMC7439365 DOI: 10.1021/acsomega.0c01741] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 07/23/2020] [Indexed: 05/04/2023]
Abstract
Lysine ubiquitination, a widely studied posttranslational modification, plays vital roles in various biological processes in eukaryotic cells. Although several studies have examined the plant ubiquitylome, no such research has been performed in tobacco, a model plant for molecular biology. Here, we comprehensively analyzed lysine ubiquitination in tobacco (Nicotiana tabacum) using LC-MS/MS along with highly sensitive immune-affinity purification. In total, 964 lysine-ubiquitinated (Kub) sites were identified in 572 proteins. Extensive bioinformatics studies revealed the distribution of these proteins in various cellular locations, including the cytoplasm, chloroplast, nucleus, and plasma membrane. Notably, 25% of the Kub proteins were located in the chloroplast of which 21 were enzymatically involved in important pathways, that is, photosynthesis and carbon fixation. Western blot analysis indicated that TMV infection can cause changes in ubiquitination levels. This is the first comprehensive proteomic analysis of lysine ubiquitination in tobacco, illustrating the vital role of ubiquitination in various physiological and biochemical processes and representing a valuable addition to the existing landscape of lysine ubiquitination.
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Affiliation(s)
- Huaixu Zhan
- Key
Laboratory of Tobacco Pest Monitoring, Controlling & Integrated
Management, Tobacco Research Institute of
Chinese Academy of Agricultural Sciences, Qingdao 266101, China
- Graduate
School of Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Liyun Song
- Key
Laboratory of Tobacco Pest Monitoring, Controlling & Integrated
Management, Tobacco Research Institute of
Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Ali Kamran
- Key
Laboratory of Tobacco Pest Monitoring, Controlling & Integrated
Management, Tobacco Research Institute of
Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Fei Han
- State
Tobacco Monopoly Administration, Beijing 100045, China
| | - Bin Li
- Sichuan
Tobacco Company, Chengdu 610017, China
| | - Zhicheng Zhou
- Hunan
Tobacco Science Institute, Changsha 410004, China
| | - Tianbo Liu
- Hunan
Tobacco Science Institute, Changsha 410004, China
| | - Lili Shen
- Key
Laboratory of Tobacco Pest Monitoring, Controlling & Integrated
Management, Tobacco Research Institute of
Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Ying Li
- Key
Laboratory of Tobacco Pest Monitoring, Controlling & Integrated
Management, Tobacco Research Institute of
Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Fenglong Wang
- Key
Laboratory of Tobacco Pest Monitoring, Controlling & Integrated
Management, Tobacco Research Institute of
Chinese Academy of Agricultural Sciences, Qingdao 266101, China
- wangfenglong@ caas.cn
| | - Jinguang Yang
- Key
Laboratory of Tobacco Pest Monitoring, Controlling & Integrated
Management, Tobacco Research Institute of
Chinese Academy of Agricultural Sciences, Qingdao 266101, China
- . Tel.: +86-532-88703236
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7
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Lesanavičius M, Aliverti A, Šarlauskas J, Čėnas N. Reactions of Plasmodium falciparum Ferredoxin:NADP + Oxidoreductase with Redox Cycling Xenobiotics: A Mechanistic Study. Int J Mol Sci 2020; 21:ijms21093234. [PMID: 32370303 PMCID: PMC7247349 DOI: 10.3390/ijms21093234] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 01/04/2023] Open
Abstract
Ferredoxin:NADP+ oxidoreductase from Plasmodium falciparum (PfFNR) catalyzes the NADPH-dependent reduction of ferredoxin (PfFd), which provides redox equivalents for the biosynthesis of isoprenoids and fatty acids in the apicoplast. Like other flavin-dependent electrontransferases, PfFNR is a potential source of free radicals of quinones and other redox cycling compounds. We report here a kinetic study of the reduction of quinones, nitroaromatic compounds and aromatic N-oxides by PfFNR. We show that all these groups of compounds are reduced in a single-electron pathway, their reactivity increasing with the increase in their single-electron reduction midpoint potential (E17). The reactivity of nitroaromatics is lower than that of quinones and aromatic N-oxides, which is in line with the differences in their electron self-exchange rate constants. Quinone reduction proceeds via a ping-pong mechanism. During the reoxidation of reduced FAD by quinones, the oxidation of FADH. to FAD is the possible rate-limiting step. The calculated electron transfer distances in the reaction of PfFNR with various electron acceptors are similar to those of Anabaena FNR, thus demonstrating their similar “intrinsic” reactivity. Ferredoxin stimulated quinone- and nitro-reductase reactions of PfFNR, evidently providing an additional reduction pathway via reduced PfFd. Based on the available data, PfFNR and possibly PfFd may play a central role in the reductive activation of quinones, nitroaromatics and aromatic N-oxides in P. falciparum, contributing to their antiplasmodial action.
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Affiliation(s)
- Mindaugas Lesanavičius
- Department of Xenobiotics Biochemistry, Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania; (M.L.); (J.Š.)
| | - Alessandro Aliverti
- Department of Biosciences, Università degli Studi di Milano, via Celoria 26, I-20133 Milano, Italy;
| | - Jonas Šarlauskas
- Department of Xenobiotics Biochemistry, Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania; (M.L.); (J.Š.)
| | - Narimantas Čėnas
- Department of Xenobiotics Biochemistry, Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania; (M.L.); (J.Š.)
- Correspondence: ; Tel.: +37-223-4392
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8
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Adams EM, Lampret O, König B, Happe T, Havenith M. Solvent dynamics play a decisive role in the complex formation of biologically relevant redox proteins. Phys Chem Chem Phys 2020; 22:7451-7459. [PMID: 32215444 DOI: 10.1039/d0cp00267d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron transfer processes between proteins are vital in many biological systems. Yet, the role of the solvent in influencing these redox reactions remains largely unknown. In this study, terahertz-time domain spectroscopy (THz-TDS) is used to probe the collective hydration dynamics of flavoenzyme ferredoxin-NADP+-reductase (FNR), electron transfer protein ferredoxin-1 (PetF), and the transient complex that results from their interaction. Results reveal changes in the sub-picosecond hydration dynamics that are dependent upon the surface electrostatic properties of the individual proteins and the transient complex. Retarded solvent dynamics of 8-9 ps are observed for FNR, PetF, and the FNR:PetF transient complex. Binding of the FNR:PetF complex to the substrate NADP+ results in bulk-like solvent dynamics of 7 ps, showing that formation of the ternary complex is entropically favored. Our THz measurements reveal that the electrostatic interaction of the protein surface with water results in charge sensitive changes in the solvent dynamics. Complex formation between the positively charged FNR:NADP+ pre-complex and the negatively charged PetF is not only entropically favored, but in addition the solvent reorganization into more bulk-like water assists the molecular recognition process. The change in hydration dynamics observed here suggests that the interaction with the solvent plays a significant role in mediating electron transfer processes between proteins.
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Affiliation(s)
- Ellen M Adams
- Lehrstuhl für Physkalische Chemie II, Ruhr Universität Bochum, 44801 Bochum, Germany.
| | - Oliver Lampret
- AG Photobiotechnologie, Ruhr Universität Bochum, 44801 Bochum, Germany
| | - Benedikt König
- Lehrstuhl für Physkalische Chemie II, Ruhr Universität Bochum, 44801 Bochum, Germany.
| | - Thomas Happe
- AG Photobiotechnologie, Ruhr Universität Bochum, 44801 Bochum, Germany
| | - Martina Havenith
- Lehrstuhl für Physkalische Chemie II, Ruhr Universität Bochum, 44801 Bochum, Germany.
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9
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Krishna PS, Morello G, Mamedov F. Characterization of the transient fluorescence wave phenomenon that occurs during H2 production in Chlamydomonas reinhardtii. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6321-6336. [PMID: 31504725 PMCID: PMC6859737 DOI: 10.1093/jxb/erz380] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 08/14/2019] [Indexed: 05/10/2023]
Abstract
The redox state of the plastoquinone (PQ) pool in sulfur-deprived, H2-producing Chlamydomonas reinhardtii cells was studied using single flash-induced variable fluorescence decay kinetics. During H2 production, the fluorescence decay kinetics exhibited an unusual post-illumination rise of variable fluorescence, giving a wave-like appearance. The wave showed the transient fluorescence minimum at ~60 ms after the flash, followed by a rise, reaching the transient fluorescence maximum at ~1 s after the flash, before decaying back to the initial fluorescence level. Similar wave-like fluorescence decay kinetics have been reported previously in anaerobically incubated cyanobacteria but not in green algae. From several different electron and proton transfer inhibitors used, polymyxin B, an inhibitor of type II NAD(P)H dehydrogenase (NDA2), had the effect of eliminating the fluorescence wave feature, indicating involvement of NDA2 in this phenomenon. This was further confirmed by the absence of the fluorescence wave in the Δnda2 mutant lacking NDA2. Additionally, Δnda2 mutants have also shown delayed and diminished H2 production (only 23% if compared with the wild type). Our results show that the fluorescence wave phenomenon in C. reinhardtii is observed under highly reducing conditions and is induced by the NDA2-mediated electron flow from the reduced stromal components to the PQ pool. Therefore, the fluorescence wave phenomenon is a sensitive probe for the complex network of redox reactions at the PQ pool level in the thylakoid membrane. It could be used in further characterization and improvement of the electron transfer pathways leading to H2 production in C. reinhardtii.
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Affiliation(s)
- Pilla Sankara Krishna
- Molecular Biomimetics, Department of Chemistry – Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Giorgio Morello
- Molecular Biomimetics, Department of Chemistry – Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry – Ångström Laboratory, Uppsala University, Uppsala, Sweden
- Correspondence:
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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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11
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Wiegand K, Winkler M, Rumpel S, Kannchen D, Rexroth S, Hase T, Farès C, Happe T, Lubitz W, Rögner M. Rational redesign of the ferredoxin-NADP +-oxido-reductase/ferredoxin-interaction for photosynthesis-dependent H 2-production. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:253-262. [PMID: 29378161 DOI: 10.1016/j.bbabio.2018.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/18/2018] [Accepted: 01/22/2018] [Indexed: 01/11/2023]
Abstract
Utilization of electrons from the photosynthetic water splitting reaction for the generation of biofuels, commodities as well as application in biotransformations requires a partial rerouting of the photosynthetic electron transport chain. Due to its rather negative redox potential and its bifurcational function, ferredoxin at the acceptor side of Photosystem 1 is one of the focal points for such an engineering. With hydrogen production as model system, we show here the impact and potential of redox partner design involving ferredoxin (Fd), ferredoxin-oxido-reductase (FNR) and [FeFe]‑hydrogenase HydA1 on electron transport in a future cyanobacterial design cell of Synechocystis PCC 6803. X-ray-structure-based rational design and the allocation of specific interaction residues by NMR-analysis led to the construction of Fd- and FNR-mutants, which in appropriate combination enabled an about 18-fold enhanced electron flow from Fd to HydA1 (in competition with equimolar amounts of FNR) in in vitro assays. The negative impact of these mutations on the Fd-FNR electron transport which indirectly facilitates H2 production (with a contribution of ≤42% by FNR variants and ≤23% by Fd-variants) and the direct positive impact on the Fd-HydA1 electron transport (≤23% by Fd-mutants) provide an excellent basis for the construction of a hydrogen-producing design cell and the study of photosynthetic efficiency-optimization with cyanobacteria.
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Affiliation(s)
- K Wiegand
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - M Winkler
- Photobiotechnology, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - S Rumpel
- Max-Planck-Institut für Chemische Energiekonversion, 45470 Mülheim, Germany
| | - D Kannchen
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - S Rexroth
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - T Hase
- Institute for Protein Research, Osaka University, Suita 565-0871, Osaka, Japan
| | - C Farès
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim, Germany
| | - T Happe
- Photobiotechnology, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - W Lubitz
- Max-Planck-Institut für Chemische Energiekonversion, 45470 Mülheim, Germany
| | - M Rögner
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany.
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12
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Mulo P, Medina M. Interaction and electron transfer between ferredoxin-NADP + oxidoreductase and its partners: structural, functional, and physiological implications. PHOTOSYNTHESIS RESEARCH 2017; 134:265-280. [PMID: 28361449 DOI: 10.1007/s11120-017-0372-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/20/2017] [Indexed: 05/25/2023]
Abstract
Ferredoxin-NADP+ reductase (FNR) catalyzes the last step of linear electron transfer in photosynthetic light reactions. The FAD cofactor of FNR accepts two electrons from two independent reduced ferredoxin molecules (Fd) in two sequential steps, first producing neutral semiquinone and then the fully anionic reduced, or hydroquinone, form of the enzyme (FNRhq). FNRhq transfers then both electrons in a single hydride transfer step to NADP+. We are presenting the recent progress in studies focusing on Fd:FNR interaction and subsequent electron transfer processes as well as on interaction of FNR with NADP+/H followed by hydride transfer, both from the structural and functional point of views. We also present the current knowledge about the physiological role(s) of various FNR isoforms present in the chloroplasts of higher plants and the functional impact of subchloroplastic location of FNR. Moreover, open questions and current challenges about the structure, function, and physiology of FNR are discussed.
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Affiliation(s)
- Paula Mulo
- Molecular Plant Biology, University of Turku, 20520, Turku, Finland
| | - Milagros Medina
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences, and Institute of Biocomputation and Physics of Complex Systems (Joint Units: BIFI-IQFR and GBsC-CSIC), University of Zaragoza, 50009, Zaragoza, Spain.
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13
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Kean KM, Carpenter RA, Pandini V, Zanetti G, Hall AR, Faber R, Aliverti A, Karplus PA. High-resolution studies of hydride transfer in the ferredoxin:NADP + reductase superfamily. FEBS J 2017; 284:3302-3319. [PMID: 28783258 DOI: 10.1111/febs.14190] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/28/2017] [Accepted: 08/03/2017] [Indexed: 01/19/2023]
Abstract
Ferredoxin: NADP+ reductase (FNR) is an FAD-containing enzyme best known for catalysing the transfer of electrons from ferredoxin (Fd) to NADP+ to make NADPH during photosynthesis. It is also the prototype for a broad enzyme superfamily, including the NADPH oxidases (NOXs) that all catalyse similar FAD-enabled electron transfers between NAD(P)H and one-electron carriers. Here, we define further mechanistic details of the NAD(P)H ⇌ FAD hydride-transfer step of the reaction based on spectroscopic studies and high-resolution (~ 1.5 Å) crystallographic views of the nicotinamide-flavin interaction in crystals of corn root FNR Tyr316Ser and Tyr316Ala variants soaked with either nicotinamide, NADP+ , or NADPH. The spectra obtained from FNR crystal complexes match those seen in solution and the complexes reveal active site packing interactions and patterns of covalent distortion of the FAD that imply significant active site compression that would favour catalysis. Furthermore, anisotropic B-factors show that the mobility of the C4 atom of the nicotinamide in the FNR:NADP+ complex has a directionality matching that expected for boat-like excursions of the nicotinamide ring thought to enhance hydride transfer. Arguments are made for the relevance of this binding mode to catalysis, and specific consideration is given to how the results extrapolate to provide insight to structure-function relations for the membrane-bound NOX enzymes for which little structural information has been available. DATABASES Structural data are available in the PDB database under the accession numbers 3LO8 (wild-type), 5VW4 [Y316S:nicotinamide (P32 21)], 5VW9 [Y316S:nicotinamide (P31 21)], 5VW3 [Y316S:NADP+ (P32 21)], 5VW8 [Y316S:NADP+ (P31 21)], 5VW2 [Y316S:NADPH (P32 21)], 5VW5 [Y316A:nicotinamide (P32 21)], 5VW6 [Y316A:NADP+ (P32 21)], 5VW7 [Y316A:NADPH (P32 21)], 5VWA [Y316F (P32 21)], and 5VWB [Y316F:NADP+ (P31 21)]. Enzyme Commission number: ferredoxin:NADP+ reductase - E C1.18.1.2.
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Affiliation(s)
- Kelsey M Kean
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Russell A Carpenter
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Vittorio Pandini
- Department of Biosciences, Università degli Studi di Milano, Italy
| | - Giuliana Zanetti
- Department of Biosciences, Università degli Studi di Milano, Italy
| | - Andrea R Hall
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Rick Faber
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | | | - P Andrew Karplus
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
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14
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Quaranta A, Lagoutte B, Frey J, Sétif P. Photoreduction of the ferredoxin/ferredoxin-NADP(+)-reductase complex by a linked ruthenium polypyridyl chromophore. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 160:347-54. [PMID: 27180037 DOI: 10.1016/j.jphotobiol.2016.04.030] [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: 04/15/2015] [Revised: 04/26/2016] [Accepted: 04/28/2016] [Indexed: 11/18/2022]
Abstract
Photosynthetic ferredoxin and its main partner ferredoxin-NADP(+)-reductase (FNR) are key proteins during the photoproduction of reductive power involved in photosynthetic growth. In this work, we used covalent attachment of ruthenium derivatives to different cysteine mutants of ferredoxin to trigger by laser-flash excitation both ferredoxin reduction and subsequent electron transfer from reduced ferredoxin to FNR. Rates and yields of reduction of the ferredoxin [2Fe-2S] cluster by reductively quenched Ru* could be measured for the first time for such a low redox potential protein whereas ferredoxin-FNR electron transfer was characterized in detail for one particular Ru-ferredoxin covalent adduct. For this adduct, the efficiency of FNR single reduction by reduced ferredoxin was close to 100% under both first-order and diffusion-limited second-order conditions. Interprotein intracomplex electron transfer was measured unambiguously for the first time with a fast rate of c. 6500s(-1). Our measurements point out that Ru photosensitizing is a powerful approach to study the functional interactions of ferredoxin with its numerous partners besides FNR.
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Affiliation(s)
- Annamaria Quaranta
- CEA, iBiTec-S/SB2SM, CEA Saclay, 91191 Gif sur Yvette, France; Université Paris-Saclay, I2BC, UMR 9198, 91190 Gif sur Yvette, France
| | | | - Julien Frey
- CEA, iBiTec-S/SB2SM, CEA Saclay, 91191 Gif sur Yvette, France
| | - Pierre Sétif
- CEA, iBiTec-S/SB2SM, CEA Saclay, 91191 Gif sur Yvette, France; Université Paris-Saclay, I2BC, UMR 9198, 91190 Gif sur Yvette, France.
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15
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Seo D, Soeta T, Sakurai H, Sétif P, Sakurai T. Pre-steady-state kinetic studies of redox reactions catalysed by Bacillus subtilis ferredoxin-NADP(+) oxidoreductase with NADP(+)/NADPH and ferredoxin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:678-87. [PMID: 26965753 DOI: 10.1016/j.bbabio.2016.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 02/12/2016] [Accepted: 03/01/2016] [Indexed: 11/30/2022]
Abstract
Ferredoxin-NADP(+) oxidoreductase ([EC1.18.1.2], FNR) from Bacillus subtilis (BsFNR) is a homodimeric flavoprotein sharing structural homology with bacterial NADPH-thioredoxin reductase. Pre-steady-state kinetics of the reactions of BsFNR with NADP(+), NADPH, NADPD (deuterated form) and B. subtilis ferredoxin (BsFd) using stopped-flow spectrophotometry were studied. Mixing BsFNR with NADP(+) and NADPH yielded two types of charge-transfer (CT) complexes, oxidized FNR (FNR(ox))-NADPH and reduced FNR (FNR(red))-NADP(+), both having CT absorption bands centered at approximately 600n m. After mixing BsFNR(ox) with about a 10-fold molar excess of NADPH (forward reaction), BsFNR was almost completely reduced at equilibrium. When BsFNR(red) was mixed with NADP(+), the amount of BsFNR(ox) increased with increasing NADP(+) concentration, but BsFNR(red) remained as the major species at equilibrium even with about 50-fold molar excess NADP(+). In both directions, the hydride-transfer was the rate-determining step, where the forward direction rate constant (~500 s(-1)) was much higher than the reverse one (<10 s(-1)). Mixing BsFd(red) with BsFNR(ox) induced rapid formation of a neutral semiquinone form. This process was almost completed within 1 ms. Subsequently the neutral semiquinone form was reduced to the hydroquinone form with an apparent rate constant of 50 to 70 s(-1) at 10°C, which increased as BsFd(red) increased from 40 to 120 μM. The reduction rate of BsFNR(ox) by BsFd(red) was markedly decreased by premixing BsFNR(ox) with BsFd(ox), indicating that the dissociation of BsFd(ox) from BsFNR(sq) is rate-limiting in the reaction. The characteristics of the BsFNR reactions with NADP(+)/NADPH were compared with those of other types of FNRs.
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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.
| | - Takahiro Soeta
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Hidehiro Sakurai
- Research Institute for Photobiological Hydrogen Production, Kanagawa University, Tsuchiya, Hiratsuka, Kanagawa 259-1293, Japan
| | - Pierre Sétif
- CEA, iBiTecS, 91191 Gif sur Yvette, France; CNRS/Université Paris-Sud/CEA, I2BC, 91190 Gif sur Yvette, France
| | - Takeshi Sakurai
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
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16
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Koga K, Matsubara Y, Kosaka T, Koike K, Morimoto T, Ishitani O. Hydride Reduction of NAD(P)+ Model Compounds with a Ru(II)–Hydrido Complex. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00713] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kichitaro Koga
- Department of Chemistry,
Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1-NE-1, Meguro-ku, Tokyo 152-8550, Japan
| | - Yasuo Matsubara
- Department
of Material and Life Chemistry, Kanagawa University, Rokkakubashi
3-27-1, Kanagawa-ku, Yokohama 221-8686, Japan
| | - Tatsumi Kosaka
- Graduate School of
Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570, Japan
| | - Kazuhide Koike
- National Institute of Advanced Industrial Science and Technology, Onogawa 16-1, Tsukuba 305-8569, Japan
| | - Tatsuki Morimoto
- Department of Applied Chemistry, School of Engineering, Tokyo University of Technology, 1401-1 Katakura, Hachioji, Tokyo 192-0982, Japan
| | - Osamu Ishitani
- Department of Chemistry,
Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1-NE-1, Meguro-ku, Tokyo 152-8550, Japan
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17
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Kinoshita M, Kim JY, Kume S, Sakakibara Y, Sugiki T, Kojima C, Kurisu G, Ikegami T, Hase T, Kimata-Ariga Y, Lee YH. Physicochemical nature of interfaces controlling ferredoxin NADP(+) reductase activity through its interprotein interactions with ferredoxin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1200-11. [PMID: 26087388 DOI: 10.1016/j.bbabio.2015.05.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/27/2015] [Accepted: 05/29/2015] [Indexed: 01/27/2023]
Abstract
Although acidic residues of ferredoxin (Fd) are known to be essential for activities of various Fd-dependent enzymes, including ferredoxin NADP(+) reductase (FNR) and sulfite reductase (SiR), through electrostatic interactions with basic residues of partner enzymes, non-electrostatic contributions such as hydrophobic forces remain largely unknown. We herein demonstrated that intermolecular hydrophobic and charge-charge interactions between Fd and enzymes were both critical for enzymatic activity. Systematic site-directed mutagenesis, which altered physicochemical properties of residues on the interfaces of Fd for FNR /SiR, revealed various changes in activities of both enzymes. The replacement of serine 43 of Fd to a hydrophobic residue (S43W) and charged residue (S43D) increased and decreased FNR activity, respectively, while S43W showed significantly lower SiR activity without affecting SiR activity by S43D, suggesting that hydrophobic and electrostatic interprotein forces affected FNR activity. Enzyme kinetics revealed that changes in FNR activity by mutating Fd correlated with Km, but not with kcat or activation energy, indicating that interprotein interactions determined FNR activity. Calorimetry-based binding thermodynamics between Fd and FNR showed different binding modes of FNR to wild-type, S43W, or S43D, which were controlled by enthalpy and entropy, as shown by the driving force plot. Residue-based NMR spectroscopy of (15)N FNR with Fds also revealed distinct binding modes of each complex based on different directions of NMR peak shifts with similar overall chemical shift differences. We proposed that subtle adjustments in both hydrophobic and electrostatic forces were critical for enzymatic activity, and these results may be applicable to protein-based electron transfer systems.
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Affiliation(s)
- Misaki Kinoshita
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Ju Yaen Kim
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Satoshi Kume
- Cellular Function Imaging Team, Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, Kobe, Hyogo 650-0047, Japan
| | - Yukiko Sakakibara
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Toshihiko Sugiki
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Chojiro Kojima
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Takahisa Ikegami
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Toshiharu Hase
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Yoko Kimata-Ariga
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Young-Ho Lee
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
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18
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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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19
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Sánchez-Azqueta A, Herguedas B, Hurtado-Guerrero R, Hervás M, Navarro JA, Martínez-Júlvez M, Medina M. A hydrogen bond network in the active site of Anabaena ferredoxin-NADP+ reductase modulates its catalytic efficiency. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:251-63. [DOI: 10.1016/j.bbabio.2013.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 10/13/2013] [Accepted: 10/23/2013] [Indexed: 10/26/2022]
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20
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Kauny J, Sétif P. NADPH fluorescence in the cyanobacterium Synechocystis sp. PCC 6803: a versatile probe for in vivo measurements of rates, yields and pools. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:792-801. [PMID: 24463053 DOI: 10.1016/j.bbabio.2014.01.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
Abstract
We measured the kinetics of light-induced NADPH formation and subsequent dark consumption by monitoring in vivo its fluorescence in the cyanobacterium Synechocystis PCC 6803. Spectral data allowed the signal changes to be attributed to NAD(P)H and signal linearity vs the chlorophyll concentration was shown to be recoverable after appropriate correction. Parameters associated to reduction of NADP(+) to NADPH by ferredoxin-NADP(+)-oxidoreductase were determined: After single excitation of photosystem I, half of the signal rise is observed in 8ms; Evidence for a kinetic limitation which is attributed to an enzyme bottleneck is provided; After two closely separated saturating flashes eliciting two photosystem I turnovers in less than 2ms, more than 50% of the cytoplasmic photoreductants (reduced ferredoxin and photosystem I acceptors) are diverted from NADPH formation by competing processes. Signal quantitation in absolute NADPH concentrations was performed by adding exogenous NADPH to the cell suspensions and by estimating the enhancement factor of in vivo fluorescence (between 2 and 4). The size of the visible (light-dependent) NADP (NADP(+)+NADPH) pool was measured to be between 1.4 and 4 times the photosystem I concentration. A quantitative discrepancy is found between net oxygen evolution and NADPH consumption by the light-activated Calvin-Benson cycle. The present study shows that NADPH fluorescence is an efficient probe for studying in vivo the energetic metabolism of cyanobacteria which can be used for assessing multiple phenomena occurring over different time scales.
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Affiliation(s)
- Jocelyn Kauny
- iBiTec-S, CNRS UMR 8221, CEA Saclay, 91191 Gif-sur-Yvette, France.
| | - Pierre Sétif
- iBiTec-S, CNRS UMR 8221, CEA Saclay, 91191 Gif-sur-Yvette, France.
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21
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Choi HJ, Montemagno CD. Recent Progress in Advanced Nanobiological Materials for Energy and Environmental Applications. MATERIALS 2013; 6:5821-5856. [PMID: 28788424 PMCID: PMC5452742 DOI: 10.3390/ma6125821] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 11/26/2013] [Accepted: 11/28/2013] [Indexed: 11/25/2022]
Abstract
In this review, we briefly introduce our efforts to reconstruct cellular life processes by mimicking natural systems and the applications of these systems to energy and environmental problems. Functional units of in vitro cellular life processes are based on the fabrication of artificial organelles using protein-incorporated polymersomes and the creation of bioreactors. This concept of an artificial organelle originates from the first synthesis of poly(siloxane)-poly(alkyloxazoline) block copolymers three decades ago and the first demonstration of protein activity in the polymer membrane a decade ago. The increased value of biomimetic polymers results from many research efforts to find new applications such as functionally active membranes and a biochemical-producing polymersome. At the same time, foam research has advanced to the point that biomolecules can be efficiently produced in the aqueous channels of foam. Ongoing research includes replication of complex biological processes, such as an artificial Calvin cycle for application in biofuel and specialty chemical production, and carbon dioxide sequestration. We believe that the development of optimally designed biomimetic polymers and stable/biocompatible bioreactors would contribute to the realization of the benefits of biomimetic systems. Thus, this paper seeks to review previous research efforts, examine current knowledge/key technical parameters, and identify technical challenges ahead.
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Affiliation(s)
- Hyo-Jick Choi
- National Institute for Nanotechnology and Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2M9, Canada.
| | - Carlo D Montemagno
- National Institute for Nanotechnology and Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2M9, Canada.
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22
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External loops at the ferredoxin-NADP(+) reductase protein-partner binding cavity contribute to substrates allocation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:296-305. [PMID: 24321506 DOI: 10.1016/j.bbabio.2013.11.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 11/20/2013] [Accepted: 11/27/2013] [Indexed: 11/24/2022]
Abstract
Ferredoxin-NADP(+) reductase (FNR) is the structural prototype of a family of FAD-containing reductases that catalyze electron transfer between low potential proteins and NAD(P)(+)/H, and that display a two-domain arrangement with an open cavity at their interface. The inner part of this cavity accommodates the reacting atoms during catalysis. Loops at its edge are highly conserved among plastidic FNRs, suggesting that they might contribute to both flavin stabilization and competent disposition of substrates. Here we pay attention to two of these loops in Anabaena FNR. The first is a sheet-loop-sheet motif, loop102-114, that allocates the FAD adenosine. It was thought to determine the extended FAD conformation, and, indirectly, to modulate isoalloxazine electronic properties, partners binding, catalytic efficiency and even coenzyme specificity. The second, loop261-269, contains key residues for the allocation of partners and coenzyme, including two glutamates, Glu267 and Glu268, proposed as candidates to facilitate the key displacement of the C-terminal tyrosine (Tyr303) from its stacking against the isoalloxazine ring during the catalytic cycle. Our data indicate that the main function of loop102-114 is to provide the inter-domain cavity with flexibility to accommodate protein partners and to guide the coenzyme to the catalytic site, while the extended conformation of FAD must be induced by other protein determinants. Glu267 and Glu268 appear to assist the conformational changes that occur in the loop261-269 during productive coenzyme binding, but their contribution to Tyr303 displacement is minor than expected. Additionally, loop261-269 appears a determinant to ensure reversibility in photosynthetic FNRs.
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23
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Bortolotti A, Sánchez-Azqueta A, Maya CM, Velázquez-Campoy A, Hermoso JA, Medina M, Cortez N. The C-terminal extension of bacterial flavodoxin-reductases: involvement in the hydride transfer mechanism from the coenzyme. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:33-43. [PMID: 24016470 DOI: 10.1016/j.bbabio.2013.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 08/26/2013] [Accepted: 08/28/2013] [Indexed: 11/28/2022]
Abstract
To study the role of the mobile C-terminal extension present in bacterial class of plant type NADP(H):ferredoxin reductases during catalysis, we generated a series of mutants of the Rhodobacter capsulatus enzyme (RcFPR). Deletion of the six C-terminal amino acids beyond alanine 266 was combined with the replacement A266Y, emulating the structure present in plastidic versions of this flavoenzyme. Analysis of absorbance and fluorescence spectra suggests that deletion does not modify the general geometry of FAD itself, but increases exposure of the flavin to the solvent, prevents a productive geometry of FAD:NADP(H) complex and decreases the protein thermal stability. Although the replacement A266Y partially coats the isoalloxazine from solvent and slightly restores protein stability, this single change does not allow formation of active charge-transfer complexes commonly present in the wild-type FPR, probably due to restraints of C-terminus pliability. A proton exchange process is deduced from ITC measurements during coenzyme binding. All studied RcFPR variants display higher affinity for NADP(+) than wild-type, evidencing the contribution of the C-terminus in tempering a non-productive strong (rigid) interaction with the coenzyme. The decreased catalytic rate parameters confirm that the hydride transfer from NADPH to the flavin ring is considerably hampered in the mutants. Although the involvement of the C-terminal extension from bacterial FPRs in stabilizing overall folding and bent-FAD geometry has been stated, the most relevant contributions to catalysis are modulation of coenzyme entrance and affinity, promotion of the optimal geometry of an active complex and supply of a proton acceptor acting during coenzyme binding.
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Affiliation(s)
- Ana Bortolotti
- Instituto de Biología Molecular y Celular de Rosario, Universidad Nacional de Rosario & CONICET, Rosario, Argentina
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24
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Hanke G, Mulo P. Plant type ferredoxins and ferredoxin-dependent metabolism. PLANT, CELL & ENVIRONMENT 2013; 36:1071-1084. [PMID: 23190083 DOI: 10.1111/pce.12046] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 11/19/2012] [Accepted: 11/20/2012] [Indexed: 05/24/2023]
Abstract
Ferredoxin (Fd) is a small [2Fe-2S] cluster-containing protein found in all organisms performing oxygenic photosynthesis. Fd is the first soluble acceptor of electrons on the stromal side of the chloroplast electron transport chain, and as such is pivotal to determining the distribution of these electrons to different metabolic reactions. In chloroplasts, the principle sink for electrons is in the production of NADPH, which is mostly consumed during the assimilation of CO2 . In addition to this primary function in photosynthesis, Fds are also involved in a number of other essential metabolic reactions, including biosynthesis of chlorophyll, phytochrome and fatty acids, several steps in the assimilation of sulphur and nitrogen, as well as redox signalling and maintenance of redox balance via the thioredoxin system and Halliwell-Asada cycle. This makes Fds crucial determinants of the electron transfer between the thylakoid membrane and a variety of soluble enzymes dependent on these electrons. In this article, we will first describe the current knowledge on the structure and function of the various Fd isoforms present in chloroplasts of higher plants and then discuss the processes involved in oxidation of Fd, introducing the corresponding enzymes and discussing what is known about their relative interaction with Fd.
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Affiliation(s)
- Guy Hanke
- Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076, Osnabrück, Germany
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25
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Sánchez-Azqueta A, Musumeci MA, Martínez-Júlvez M, Ceccarelli EA, Medina M. Structural backgrounds for the formation of a catalytically competent complex with NADP(H) during hydride transfer in ferredoxin-NADP(+) reductases. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1817:1063-71. [PMID: 22542899 DOI: 10.1016/j.bbabio.2012.04.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 04/11/2012] [Accepted: 04/12/2012] [Indexed: 11/21/2022]
Abstract
The role of the highly conserved C266 and L268 of pea ferredoxin-NADP(+) reductase (FNR) in formation of the catalytically competent complex of the enzyme with NADP(H) was investigated. Previous studies suggest that the volume of these side-chains, situated facing the side of the C-terminal Y308 catalytic residue not stacking the flavin isoalloxazine ring, may be directly involved in the fine-tuning of the catalytic efficiency of the enzyme. Wild-type pea FNR as well as single and double mutants of C266 and L268 residues were analysed by fast transient-kinetic techniques and their midpoint reduction potentials were determined. For the C266A, C266M and C266A/L268A mutants a significant reduction in the overall hydride transfer (HT) rates was observed along with the absence of charge-transfer complex formation. The HT rate constants for NADPH oxidation were lower than those for NADP(+) reduction, reaching a 30-fold decrease in the double mutant. In agreement, these variants exhibited more negative midpoint potentials with respect to the wild-type enzyme. The three-dimensional structures of C266M and L268V variants were solved. The C266M mutant shows a displacement of E306 away from the relevant residue S90 to accommodate the bulky methionine introduced. The overall findings indicate that in FNR the volume of the residue at position 266 is essential to attain the catalytic architecture between the nicotinamide and isoalloxazine rings at the active site and, therefore, for an efficient HT process. In addition, flexibility of the 268-270 loop appears to be critical for FNR to achieve catalytically competent complexes with NADP(H).
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Affiliation(s)
- Ana Sánchez-Azqueta
- Departamento de Bioquímica y Biología Molecular y Celular, Institute of Biocomputation and Physics of Complex Systems, Universidad de Zaragoza, Spain
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Ellis HR. Mechanism for sulfur acquisition by the alkanesulfonate monooxygenase system. Bioorg Chem 2011; 39:178-84. [DOI: 10.1016/j.bioorg.2011.08.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 08/01/2011] [Accepted: 08/03/2011] [Indexed: 11/28/2022]
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The transient catalytically competent coenzyme allocation into the active site of Anabaena ferredoxin NADP+ -reductase. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 41:117-28. [PMID: 21538059 DOI: 10.1007/s00249-011-0704-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 04/05/2011] [Indexed: 10/18/2022]
Abstract
Ferredoxin-NADP(+) reductase (FNR) catalyses the electron transfer from ferredoxin to NADP(+) via its flavin FAD cofactor. A molecular dynamics theoretical approach is applied here to visualise the transient catalytically competent interaction of Anabaena FNR with its coenzyme, NADP(+). The particular role of some of the residues identified as key in binding and accommodating the 2'P-AMP moiety of the coenzyme is confirmed in molecular terms. Simulations also indicate that the architecture of the active site precisely contributes to the orientation of the N5 of the FAD isoalloxazine ring and the C4 of the coenzyme nicotinamide ring in the conformation of the catalytically competent hydride transfer complex and, therefore, contributes to the efficiency of the process. In particular, the side chain of the C-terminal Y303 in Anabaena FNR appears key to providing the optimum geometry by reducing the stacking probability between the isoalloxazine and nicotinamide rings, thus providing the required co-linearity and distance among the N5 of the flavin cofactor, the C4 of the coenzyme nicotinamide and the hydride that has to be transferred between them. All these factors are highly related to the reaction efficiency, mechanism and reversibility of the process.
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Nijvipakul S, Ballou DP, Chaiyen P. Reduction kinetics of a flavin oxidoreductase LuxG from Photobacterium leiognathi (TH1): half-sites reactivity. Biochemistry 2010; 49:9241-8. [PMID: 20836540 DOI: 10.1021/bi1009985] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacterial bioluminescence is a phenomenon resulting from the reaction of a two-component FMN-dependent aldehyde monooxygenase system, which comprises a bacterial luciferase and a flavin reductase. Bacterial luciferase (LuxAB) is one of the most extensively investigated two-component monooxygenases, while its reductase partner, the flavin reductase (LuxG) from the same operon, has only been recently expressed in a functional form. This work reports transient kinetics identification of intermediates in the LuxG reaction using stopped-flow spectrophotometry. The results indicate that the overall reaction follows a sequential-ordered mechanism in which NADH binds first to the enzyme, followed by FMN, resulting in the formation of charge-transfer intermediate 1 (CT-1) typical of those between reduced pyridine nucleotides and oxidized flavins. The next step is the reduction of FMN as indicated by a large decrease in absorbance at 450 nm. The reduction of FMN is biphasic. The first phase of FMN reduction occurs concurrently with formation of charge-transfer intermediate 2 (CT-2), while the second phase is synchronous with the decay of CT-2. When the isotope-labeled substrate, 4(R)-[(2)H]NADH, was used, the first reduction phase showed a primary kinetic isotope effect ((D)k(red)) of ≥3.9 and resulted in greater accumulation of CT-1. These results are consistent with CT-1 being the FMN(ox):NADH complex, while CT-2 is the FMN(red):NAD(+) complex. Because CT-2 decays with a rate constant of 2.8 ± 0.2 s(-1), while the turnover number obtained from the steady-steady-state kinetics is 1.7 s(-1), it is likely that the CT-2 decay step largely controls the overall reaction rate. All kinetic data are consistent with a half-sites reactivity model in which flavin reduction occurs at only one subunit at a time. The first reduction phase is due to the reduction of FMN in the first subunit, while the second phase is due to the reduction of FMN in the second subunit. The latter phase is limited by the rate of decay of CT-2 in the first subunit. The half-sites reactivity model is also supported by detection of burst kinetics during the pre-steady-state period that is correlated with 0.5 mol of the FMN being reduced/mol of the LuxG:NADH complex. The functional importance of this half-site reactivity phenomenon is still unclear.
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Affiliation(s)
- Sarayut Nijvipakul
- Department of Biochemistry and Center of Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Bangkok, Thailand
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Kimata-Ariga Y, Sakakibara Y, Ikegami T, Hase T. Electron transfer of site-specifically cross-linked complexes between ferredoxin and ferredoxin-NADP(+) reductase. Biochemistry 2010; 49:10013-23. [PMID: 20954716 DOI: 10.1021/bi100855a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ferredoxin (Fd) and Fd-NADP(+) reductase (FNR) are redox partners responsible for the conversion between NADP(+) and NADPH in the plastids of photosynthetic organisms. Introduction of specific disulfide bonds between Fd and FNR by engineering cysteines into the two proteins resulted in 13 different Fd-FNR cross-linked complexes displaying a broad range of activity to catalyze the NADPH-dependent cytochrome c reduction. This variability in activity was thought to be mainly due to different levels of intramolecular electron transfer activity between the FNR and Fd domains. Stopped-flow analysis revealed such differences in the rate of electron transfer from the FNR to Fd domains in some of the cross-linked complexes. A group of the cross-linked complexes with high cytochrome c reduction activity comparable to dissociable wild-type Fd/FNR was shown to assume a similar Fd-FNR interaction mode as in the native Fd:FNR complex by analyses of NMR chemical shift perturbation and absorption spectroscopy. However, the intermolecular electron transfer of these cross-linked complexes with two Fd-binding proteins, nitrite reductase and photosystem I, was largely inhibited, most probably due to steric hindrance by the FNR moiety linked near the redox center of the Fd domain. In contrast, another group of the cross-linked complexes with low cytochrome c reduction activity tends to mediate higher intermolecular electron transfer activity. Therefore, reciprocal relationship of intramolecular and intermolecular electron transfer abilities was conferred by the linkage of Fd and FNR, which may explain the physiological significance of the separate forms of Fd and FNR in chloroplasts.
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Affiliation(s)
- Yoko Kimata-Ariga
- Laboratory of Regulation of Biological Reactions, Institute for Protein Research,Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Chloroplast-targeted ferredoxin-NADP(+) oxidoreductase (FNR): structure, function and location. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:927-34. [PMID: 20934402 DOI: 10.1016/j.bbabio.2010.10.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 10/01/2010] [Accepted: 10/02/2010] [Indexed: 11/20/2022]
Abstract
Ferredoxin-NADP(+) oxidoreductase (FNR) is a ubiquitous flavin adenine dinucleotide (FAD)-binding enzyme encoded by a small nuclear gene family in higher plants. The chloroplast targeted FNR isoforms are known to be responsible for the final step of linear electron flow transferring electrons from ferredoxin to NADP(+), while the putative role of FNR in cyclic electron transfer has been under discussion for decades. FNR has been found from three distinct chloroplast compartments (i) at the thylakoid membrane, (ii) in the soluble stroma, and (iii) at chloroplast inner envelope. Recent in vivo studies have indicated that besides the membrane-bound FNR, also the soluble FNR is photosynthetically active. Two chloroplast proteins, Tic62 and TROL, were recently identified and shown to form high molecular weight protein complexes with FNR at the thylakoid membrane, and thus seem to act as the long-sought molecular anchors of FNR to the thylakoid membrane. Tic62-FNR complexes are not directly involved in photosynthetic reactions, but Tic62 protects FNR from inactivation during the dark periods. TROL-FNR complexes, however, have an impact on the photosynthetic performance of the plants. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
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Lans I, Peregrina JR, Medina M, Garcia-Viloca M, González-Lafont A, Lluch JM. Mechanism of the hydride transfer between Anabaena Tyr303Ser FNR(rd)/FNR(ox) and NADP+/H. A combined pre-steady-state kinetic/ensemble-averaged transition-state theory with multidimensional tunneling study. J Phys Chem B 2010; 114:3368-79. [PMID: 20163096 DOI: 10.1021/jp912034m] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The flavoenzyme ferredoxin-NADP(+) reductase (FNR) catalyzes the production of NADPH during photosynthesis. The hydride-transfer reactions between the Anabaena mutant Tyr303Ser FNR(rd)/FNR(ox) and NADP(+)/H have been studied both experimentally and theoretically. Stopped-flow pre-steady-state kinetic measurements have shown that, in contrast to that observed for WT FNR, the physiological hydride transfer from Tyr303Ser FNR(rd) to NADP(+) does not occur. Conversely, the reverse reaction does take place with a rate constant just slightly slower than for WT FNR. This latter process shows temperature-dependent rates, but essentially temperature independent kinetic isotope effects, suggesting the reaction takes place following the vibration-driven tunneling model. In turn, ensemble-averaged variational transition-state theory with multidimensional tunneling calculations provide reaction rate constant values and kinetic isotope effects that agree with the experimental results, the experimental and the theoretical values for the reverse process being noticeably similar. The reaction mechanism behind these hydride transfers has been analyzed. The formation of a close contact ionic pair FADH(-):NADP(+) surrounded by the polar environment of the enzyme in the reactant complex of the mutant might be the cause of the huge difference between the direct and the reverse reaction.
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Affiliation(s)
- Isaias Lans
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, and Institute of Biocomputation and Physics of Complex Systems (BIFI), Universidad de Zaragoza, E-50009 Zaragoza, Spain
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Dumit VI, Essigke T, Cortez N, Ullmann GM. Mechanistic insights into ferredoxin-NADP(H) reductase catalysis involving the conserved glutamate in the active site. J Mol Biol 2010; 397:814-25. [PMID: 20132825 DOI: 10.1016/j.jmb.2010.01.063] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 01/26/2010] [Accepted: 01/27/2010] [Indexed: 11/15/2022]
Abstract
Plant-type ferredoxin-NADP(H) reductases (FNRs) are flavoenzymes harboring one molecule of noncovalently bound flavin adenine dinucleotide that catalyze reversible reactions between obligatory one-electron carriers and obligatory two-electron carriers. A glutamate next to the C-terminus is strictly conserved in FNR and has been proposed to function as proton donor/acceptor during catalysis. However, experimental studies of this proposed function led to contradicting conclusions about the role of this glutamate in the catalytic mechanism. In the present work, we study the titration behavior of the glutamate in the active site of FNR using theoretical methods. Protonation probabilities for maize FNR were computed for the reaction intermediates of the catalytic cycle by Poisson-Boltzmann electrostatic calculations and Metropolis Monte Carlo titration. The titration behavior of the highly conserved glutamate was found to vary depending on the bound substrates NADP(H) and ferredoxin and also on the redox states of these substrates and the flavin adenine dinucleotide. Our results support the involvement of the glutamate in the FNR catalytic mechanism not only as a proton donor but also as a key residue for stabilizing and destabilizing reaction intermediates. On the basis of our findings, we propose a model rationalizing the function of the glutamate in the reaction cycle, which allows reinterpretation of previous experimental results.
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Affiliation(s)
- Verónica I Dumit
- Structural Biology/Bioinformatics, University of Bayreuth, Bayreuth, Germany
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Korn A, Ajlani G, Lagoutte B, Gall A, Sétif P. Ferredoxin:NADP+ oxidoreductase association with phycocyanin modulates its properties. J Biol Chem 2009; 284:31789-97. [PMID: 19759024 DOI: 10.1074/jbc.m109.024638] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In photosynthetic organisms, ferredoxin:NADP(+) oxidoreductase (FNR) is known to provide NADPH for CO(2) assimilation, but it also utilizes NADPH to provide reduced ferredoxin. The cyanobacterium Synechocystis sp. strain PCC6803 produces two FNR isoforms, a small one (FNR(S)) similar to the one found in plant plastids and a large one (FNR(L)) that is associated with the phycobilisome, a light-harvesting complex. Here we show that a mutant lacking FNR(L) exhibits a higher NADP(+)/NADPH ratio. We also purified to homogeneity a phycobilisome subcomplex comprising FNR(L,) named FNR(L)-PC. The enzymatic activities of FNR(L)-PC were compared with those of FNR(S). During NADPH oxidation, FNR(L)-PC exhibits a 30% decrease in the Michaelis constant K(m)((NADPH)), and a 70% increase in K(m)((ferredoxin)), which is in agreement with its predicted lower activity of ferredoxin reduction. During NADP(+) reduction, the FNR(L)-PC shows a 29/43% decrease in the rate of single electron transfer from reduced ferredoxin in the presence/absence of NADP(+). The increase in K(m)((ferredoxin)) and the rate decrease of single reduction are attributed to steric hindrance by the phycocyanin moiety of FNR(L)-PC. Both isoforms are capable of catalyzing the NADP(+) reduction under multiple turnover conditions. Furthermore, we obtained evidence that, under high ionic strength conditions, electron transfer from reduced ferredoxin is rate limiting during this process. The differences that we observe might not fully explain the in vivo properties of the Synechocystis mutants expressing only one of the isoforms. Therefore, we advocate that FNR localization and/or substrates availability are essential in vivo.
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Affiliation(s)
- Anja Korn
- Institut de Biologie et de Technologie de Saclay, Commissariat à L'Energie Atomique, CNRS, F-91191 Gif sur Yvette, France
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Binding thermodynamics of ferredoxin:NADP+ reductase: two different protein substrates and one energetics. Biophys J 2009; 96:4966-75. [PMID: 19527656 DOI: 10.1016/j.bpj.2009.02.061] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 01/16/2009] [Accepted: 03/18/2009] [Indexed: 11/22/2022] Open
Abstract
The thermodynamics of the formation of binary and ternary complexes between Anabaena PCC 7119 FNR and its substrates, NADP+ and Fd, or Fld, has been studied by ITC. Despite structural dissimilarities, the main difference between Fd and Fld binding to FNR relates to hydrophobicity, reflected in different binding heat capacity and number of water molecules released from the interface. At pH 8, the formation of the binary complexes is both enthalpically and entropically driven, accompanied by the protonation of at least one ionizable group. His299 FNR has been identified as the main responsible for the proton exchange observed. However, at pH 10, where no protonation occurs and intrinsic binding parameters can be obtained, the formation of the binary complexes is entropically driven, with negligible enthalpic contribution. Absence of the FMN cofactor in Fld does not alter significantly the strength of the interaction, but considerably modifies the enthalpic and entropic contributions, suggesting a different binding mode. Ternary complexes show negative cooperativity (6-fold and 11-fold reduction in binding affinity, respectively), and an increase in the enthalpic contribution (more favorable) and a decrease in the entropic contribution (less favorable), with regard to the binary complexes energetics.
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Medina M. Structural and mechanistic aspects of flavoproteins: photosynthetic electron transfer from photosystem I to NADP+. FEBS J 2009; 276:3942-58. [PMID: 19583765 DOI: 10.1111/j.1742-4658.2009.07122.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This minireview covers the research carried out in recent years into different aspects of the function of the flavoproteins involved in cyanobacterial photosynthetic electron transfer from photosystem I to NADP(+), flavodoxin and ferredoxin-NADP(+) reductase. Interactions that stabilize protein-flavin complexes and tailor the midpoint potentials in these proteins, as well as many details of the binding and electron transfer to protein and ligand partners, have been revealed. In addition to their role in photosynthesis, flavodoxin and ferredoxin-NADP(+) reductase are ubiquitous flavoenzymes that deliver NAD(P)H or low midpoint potential one-electron donors to redox-based metabolisms in plastids, mitochondria and bacteria. They are also the basic prototypes for a large family of diflavin electron transferases with common functional and structural properties. Understanding their mechanisms should enable greater comprehension of the many physiological roles played by flavodoxin and ferredoxin-NADP(+) reductase, either free or as modules in multidomain proteins. Many aspects of their biochemistry have been extensively characterized using a combination of site-directed mutagenesis, steady-state and transient kinetics, spectroscopy and X-ray crystallography. Despite these considerable advances, various key features of the structural-function relationship are yet to be explained in molecular terms. Better knowledge of these systems and their particular properties may allow us to envisage several interesting applications of these proteins beyond their physiological functions.
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Affiliation(s)
- Milagros Medina
- Departamento de Bioquímica y Biología Molecular y Celular and BFIF, Universidad de Zaragoza, Spain.
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Senda T, Senda M, Kimura S, Ishida T. Redox control of protein conformation in flavoproteins. Antioxid Redox Signal 2009; 11:1741-66. [PMID: 19243237 DOI: 10.1089/ars.2008.2348] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) are two flavin prosthetic groups utilized as the redox centers of various proteins. The conformations and chemical properties of these flavins can be affected by their redox states as well as by photoreactions. Thus, proteins containing flavin (flavoproteins) can function not only as redox enzymes, but also as signaling molecules by using the redox- and/or light-dependent changes of the flavin. Redox and light-dependent conformational changes of flavoproteins are critical to many biological signaling systems. In this review, we summarize the molecular mechanisms of the redox-dependent conformational changes of flavoproteins and discuss their relationship to signaling functions. The redox-dependent (or light-excited) changes of flavin and neighboring residues in proteins act as molecular "switches" that "turn on" various conformational changes in proteins, and can be classified into five types. On the basis of the present analysis, we recommend future directions in molecular structural research on flavoproteins and related proteins.
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Affiliation(s)
- Toshiya Senda
- Biomedicinal Information Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan.
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Paladini DH, Musumeci MA, Carrillo N, Ceccarelli EA. Induced fit and equilibrium dynamics for high catalytic efficiency in ferredoxin-NADP(H) reductases. Biochemistry 2009; 48:5760-8. [PMID: 19435322 DOI: 10.1021/bi9004232] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ferredoxin-NADP(H) reductase (FNR) is a FAD-containing protein that catalyzes the reversible transfer of electrons between NADP(H) and ferredoxin or flavodoxin. This enzyme participates in the redox-based metabolism of plastids, mitochondria, and bacteria. Plastidic plant-type FNRs are very efficient reductases in supporting photosynthesis. They have a strong preference for NADP(H) over NAD(H), consistent with the main physiological role of NADP(+) photoreduction. In contrast, FNRs from organisms with heterotrophic metabolisms or anoxygenic photosynthesis display turnover rates that are up to 100-fold lower than those of their plastidic and cyanobacterial counterparts. With the aim of elucidating the mechanisms by which plastidic enzymes achieve such high catalytic efficiencies and NADP(H) specificity, we investigated the manner in which the NADP(H) nicotinamide enters and properly binds to the catalytic site. Analyzing the interaction of different nucleotides, substrate analogues, and aromatic compounds with the wild type and the mutant Y308S-FNR from pea, we found that the interaction of the 2'-P-AMP moiety from NADP(+) induces a change that favors the interaction of the nicotinamide, thereby facilitating the catalytic process. Furthermore, the main role of the terminal tyrosine, Y308, is to destabilize the interaction of the nicotinamide with the enzyme, inducing product release and favoring discrimination of the nucleotide substrate. We determined that this function can be replaced by the addition of aromatic compounds that freely diffuse in solution and establish a dynamic equilibrium, reversing the effect of the mutation in the Y308S-FNR mutant.
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Affiliation(s)
- Darío H Paladini
- Molecular Biology Division, 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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Peregrina JR, Herguedas B, Hermoso JA, Martínez-Júlvez M, Medina M. Protein motifs involved in coenzyme interaction and enzymatic efficiency in anabaena ferredoxin-NADP+ reductase. Biochemistry 2009; 48:3109-19. [PMID: 19219975 DOI: 10.1021/bi802077c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ferredoxin-NADP+ reductases (FNRs) must determine the coenzyme specificity and allow the transient encounter between N5 of its flavin cofactor and C4 of the coenzyme nicotinamide for efficient hydride transfer. Combined site-directed replacements in different putative determinants of the FNR coenzyme specificity were simultaneously produced. The resulting variants were structurally and functionally analyzed for their binding and hydride transfer abilities to the FNR physiological coenzyme NADP+/H, as well as to NAD+/H. The previously studied Y303S mutation is the only one that significantly enhances specificity for NAD+. Combination of mutations from the pyrophosphate or 2'-phosphate regions, even including Y303S, does not improve activity with NAD+, despite structures of these FNRs show how particular coenzyme-binding regions resembled motifs found in NAD+/H-dependent enzymes of the FNR family. Therefore, the "rational approach" did not succeed well, and coenzyme specificity redesign in the FNR family will be more complex than that anticipated in other NADP+/NAD+ families.
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Affiliation(s)
- José R Peregrina
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, and Institute of Biocomputation and Physics of Complex Systems, Universidad de Zaragoza, 50009 Zaragoza, Spain
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Bogachev AV, Belevich NP, Bertsova YV, Verkhovsky MI. Primary steps of the Na+-translocating NADH:ubiquinone oxidoreductase catalytic cycle resolved by the ultrafast freeze-quench approach. J Biol Chem 2008; 284:5533-8. [PMID: 19117949 DOI: 10.1074/jbc.m808984200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Na(+)-translocating NADH:ubiquinone oxidoreductase (Na(+)-NQR) is a component of respiratory chain of various bacteria, and it generates a redox-driven transmembrane electrochemical Na(+) potential. Primary steps of the catalytic cycle of Na(+)-NQR from Vibrio harveyi were followed by the ultrafast freeze-quench approach in combination with conventional stopped-flow technique. The obtained sequence of events includes NADH binding ( approximately 1.5 x 10(7) m(-1) s(-1)), hydride ion transfer from NADH to FAD ( approximately 3.5 x 10(3) s(-1)), and partial electron separation and formation of equivalent fractions of reduced 2Fe-2S cluster and neutral semiquinone of FAD ( approximately 0.97 x 10(3) s(-1)). In the last step, a quasi-equilibrium is approached between the two states of FAD: two-electron reduced (50%) and one-electron reduced (the other 50%) species. The latter, neutral semiquinone of FAD, shares the second electron with the 2Fe-2S center. The transient midpoint redox potentials for the cofactors obtained during the fast kinetics measurements are very different from ones achieved during equilibrium redox titration and show that the functional states of the enzyme realized during its turning over cannot be modeled by the equilibrium approach.
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Affiliation(s)
- Alexander V Bogachev
- Department of Molecular Energetics of Microorganisms, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
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Bortolotti A, Pérez-Dorado I, Goñi G, Medina M, Hermoso JA, Carrillo N, Cortez N. Coenzyme binding and hydride transfer in Rhodobacter capsulatus ferredoxin/flavodoxin NADP(H) oxidoreductase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1794:199-210. [PMID: 18973834 DOI: 10.1016/j.bbapap.2008.09.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 09/12/2008] [Accepted: 09/16/2008] [Indexed: 10/21/2022]
Abstract
Ferredoxin-NADP(H) reductases catalyse the reversible hydride/electron exchange between NADP(H) and ferredoxin/flavodoxin, comprising a structurally defined family of flavoenzymes with two distinct subclasses. Those present in Gram-negative bacteria (FPRs) display turnover numbers of 1-5 s(-1) while the homologues of cyanobacteria and plants (FNRs) developed a 100-fold activity increase. We investigated nucleotide interactions and hydride transfer in Rhodobacter capsulatus FPR comparing them to those reported for FNRs. NADP(H) binding proceeds as in FNRs with stacking of the nicotinamide on the flavin, which resulted in formation of charge-transfer complexes prior to hydride exchange. The affinity of FPR for both NADP(H) and 2'-P-AMP was 100-fold lower than that of FNRs. The crystal structure of FPR in complex with 2'-P-AMP and NADP(+) allowed modelling of the adenosine ring system bound to the protein, whereas the nicotinamide portion was either not visible or protruding toward solvent in different obtained crystals. Stabilising contacts with the active site residues are different in the two reductase classes. We conclude that evolution to higher activities in FNRs was partially favoured by modification of NADP(H) binding in the initial complexes through changes in the active site residues involved in stabilisation of the adenosine portion of the nucleotide and in the mobile C-terminus of FPR.
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Affiliation(s)
- Ana Bortolotti
- Instituto de Biología Molecular y Celular de Rosario, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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41
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Rodriguez RE, Lodeyro A, Poli HO, Zurbriggen M, Peisker M, Palatnik JF, Tognetti VB, Tschiersch H, Hajirezaei MR, Valle EM, Carrillo N. Transgenic tobacco plants overexpressing chloroplastic ferredoxin-NADP(H) reductase display normal rates of photosynthesis and increased tolerance to oxidative stress. PLANT PHYSIOLOGY 2007; 143:639-49. [PMID: 17189326 PMCID: PMC1803747 DOI: 10.1104/pp.106.090449] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Accepted: 12/13/2006] [Indexed: 05/13/2023]
Abstract
Ferredoxin-NADP(H) reductase (FNR) catalyzes the last step of photosynthetic electron transport in chloroplasts, driving electrons from reduced ferredoxin to NADP+. This reaction is rate limiting for photosynthesis under a wide range of illumination conditions, as revealed by analysis of plants transformed with an antisense version of the FNR gene. To investigate whether accumulation of this flavoprotein over wild-type levels could improve photosynthetic efficiency and growth, we generated transgenic tobacco (Nicotiana tabacum) plants expressing a pea (Pisum sativum) FNR targeted to chloroplasts. The alien product distributed between the thylakoid membranes and the chloroplast stroma. Transformants grown at 150 or 700 micromol quanta m(-2) s(-1) displayed wild-type phenotypes regardless of FNR content. Thylakoids isolated from plants with a 5-fold FNR increase over the wild type displayed only moderate stimulation (approximately 20%) in the rates of electron transport from water to NADP+. In contrast, when donors of photosystem I were used to drive NADP+ photoreduction, the activity was 3- to 4-fold higher than the wild-type controls. Plants expressing various levels of FNR (from 1- to 3.6-fold over the wild type) failed to show significant differences in CO2 assimilation rates when assayed over a range of light intensities and CO2 concentrations. Transgenic lines exhibited enhanced tolerance to photooxidative damage and redox-cycling herbicides that propagate reactive oxygen species. The results suggest that photosynthetic electron transport has several rate-limiting steps, with FNR catalyzing just one of them.
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Affiliation(s)
- Ramiro E Rodriguez
- Instituto de Biología Molecular y Celular de Rosario, División Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
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42
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Gao B, Ellis HR. Mechanism of flavin reduction in the alkanesulfonate monooxygenase system. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:359-67. [PMID: 17289450 DOI: 10.1016/j.bbapap.2006.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 12/08/2006] [Accepted: 12/20/2006] [Indexed: 11/17/2022]
Abstract
The alkanesulfonate monooxygenase system from Escherichia coli is involved in scavenging sulfur from alkanesulfonates under sulfur starvation. An FMN reductase (SsuE) catalyzes the reduction of FMN by NADPH, and the reduced flavin is transferred to the monooxygenase (SsuD). Rapid reaction kinetic analyses were performed to define the microscopic steps involved in SsuE catalyzed flavin reduction. Results from single-wavelength analyses at 450 and 550 nm showed that reduction of FMN occurs in three distinct phases. Following a possible rapid equilibrium binding of FMN and NADPH to SsuE (MC-1) that occurs before the first detectable step, an initial fast phase (241 s(-1)) corresponds to the interaction of NADPH with FMN (CT-1). The second phase is a slow conversion (11 s(-1)) to form a charge-transfer complex of reduced FMNH(2) with NADP(+) (CT-2), and represents electron transfer from the pyridine nucleotide to the flavin. The third step (19 s(-1)) is the decay of the charge-transfer complex to SsuE with bound products (MC-2) or product release from the CT-2 complex. Results from isotope studies with [(4R)-(2)H]NADPH demonstrates a rate-limiting step in electron transfer from NADPH to FMN, and may imply a partial rate-limiting step from CT-2 to MC-2 or the direct release of products from CT-2. While the utilization of flavin as a substrate by the alkanesulfonate monooxygenase system is novel, the mechanism for flavin reduction follows an analogous reaction path as standard flavoproteins.
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Affiliation(s)
- Benlian Gao
- The Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA
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43
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Tejero J, Peregrina JR, Martínez-Júlvez M, Gutiérrez A, Gómez-Moreno C, Scrutton NS, Medina M. Catalytic mechanism of hydride transfer between NADP+/H and ferredoxin-NADP+ reductase from Anabaena PCC 7119. Arch Biochem Biophys 2006; 459:79-90. [PMID: 17224127 DOI: 10.1016/j.abb.2006.10.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 10/20/2006] [Accepted: 10/20/2006] [Indexed: 11/15/2022]
Abstract
The mechanism of hydride transfer between Anabaena FNR and NADP+/H was analysed using for the first time stopped-flow photodiode array detection and global analysis deconvolution. The results indicated that the initial spectral changes, occurring within the instrumental dead time upon reaction of FNR with NADP+/H, included not only the initial interaction and complex formation, but also the first subsequent steps of the sequential reactions that involve hydride transfer. Two different charge-transfer complexes formed prior and upon hydride transfer, FNRox-NADPH and FNRrd-NADP+. Detectable amounts of FNRox-NADPH were found at equilibrium, but FNRrd-NADP+ accumulated to a small extent and quickly evolved. The spectral properties of both charge-transfer complexes, for the first time in Anabaena FNR, as well as the corresponding inter-conversion hydride transfer rates were obtained. The need of an adequate initial interaction between NADP+/H and FNR, and subsequent conformational changes, was also established by studying the reactions of two FNR mutants.
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Affiliation(s)
- Jesús Tejero
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, and Institute of Biocomputation and Physics of Complex Systems (BIFI), Universidad de Zaragoza, E-50009 Zaragoza, Spain
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44
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Velazquez-Campoy A, Goñi G, Peregrina JR, Medina M. Exact analysis of heterotropic interactions in proteins: Characterization of cooperative ligand binding by isothermal titration calorimetry. Biophys J 2006; 91:1887-904. [PMID: 16766617 PMCID: PMC1544317 DOI: 10.1529/biophysj.106.086561] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Intramolecular interaction networks in proteins are responsible for heterotropic ligand binding cooperativity, a biologically important, widespread phenomenon in nature (e.g., signaling transduction cascades, enzymatic cofactors, enzymatic allosteric activators or inhibitors, gene transcription, or repression). The cooperative binding of two (or more) different ligands to a macromolecule is the underlying principle. To date, heterotropic effects have been studied mainly kinetically in enzymatic systems. Until now, approximate approaches have been employed for studying equilibrium heterotropic ligand binding effects, except in two special cases in which an exact analysis was developed: independent binding (no cooperativity) and competitive binding (maximal negative cooperativity). The exact analysis and methodology for characterizing ligand binding cooperativity interactions in the general case (any degree of cooperativity) using isothermal titration calorimetry are presented in this work. Intramolecular interaction pathways within the allosteric macromolecule can be identified and characterized using this methodology. As an example, the thermodynamic characterization of the binding interaction between ferredoxin-NADP+ reductase and its three substrates, NADP+, ferredoxin, and flavodoxin, as well as the characterization of their binding cooperativity interaction, is presented.
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Affiliation(s)
- Adrian Velazquez-Campoy
- Institute of Biocomputation and Complex Systems Physics (BIFI), Universidad de Zaragoza, Zaragoza, Spain.
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45
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Mayoral T, Martínez-Júlvez M, Pérez-Dorado I, Sanz-Aparicio J, Gómez-Moreno C, Medina M, Hermoso JA. Structural analysis of interactions for complex formation between Ferredoxin-NADP+ reductase and its protein partners. Proteins 2006; 59:592-602. [PMID: 15789405 DOI: 10.1002/prot.20450] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The three-dimensional structures of K72E, K75R, K75S, K75Q, and K75E Anabaena Ferredoxin-NADP+ reductase (FNR) mutants have been solved, and particular structural details of these mutants have been used to assess the role played by residues 72 and 75 in optimal complex formation and electron transfer (ET) between FNR and its protein redox partners Ferredoxin (Fd) and Flavodoxin (Fld). Additionally, because there is no structural information available on the interaction between FNR and Fld, a model for the FNR:Fld complex has also been produced based on the previously reported crystal structures and on that of the rat Cytochrome P450 reductase (CPR), onto which FNR and Fld have been structurally aligned, and those reported for the Anabaena and maize FNR:Fd complexes. The model suggests putative electrostatic and hydrophobic interactions between residues on the FNR and Fld surfaces at the complex interface and provides an adequate orientation and distance between the FAD and FMN redox centers for efficient ET without the presence of any other molecule as electron carrier. Thus, the models now available for the FNR:Fd and FNR:Fld interactions and the structures presented here for the mutants at K72 and K75 in Anabaena FNR have been evaluated in light of previous biochemical data. These structures confirm the key participation of residue K75 and K72 in complex formation with both Fd and Fld. The drastic effect in FNR activity produced by replacement of K75 by Glu in the K75E FNR variant is explained not only by the observed changes in the charge distribution on the surface of the K75E FNR mutant, but also by the formation of a salt bridge interaction between E75 and K72 that simultaneously "neutralizes" two essential positive charged side chains for Fld/Fd recognition.
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Affiliation(s)
- Tomás Mayoral
- Grupo de Cristalografía Macromolecular y Biología Estructural, Instituto Química-Física Rocasolano, C.S.I.C. Serrano 119, 28006-Madrid, Spain
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46
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Cassan N, Lagoutte B, Sétif P. Ferredoxin-NADP+ reductase. Kinetics of electron transfer, transient intermediates, and catalytic activities studied by flash-absorption spectroscopy with isolated photosystem I and ferredoxin. J Biol Chem 2005; 280:25960-72. [PMID: 15894798 DOI: 10.1074/jbc.m503742200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The electron transfer cascade from photosystem I to NADP+ was studied at physiological pH by flash-absorption spectroscopy in a Synechocystis PCC6803 reconstituted system comprised of purified photosystem I, ferredoxin, and ferredoxin-NADP+ reductase. Experiments were conducted with a 34-kDa ferredoxin-NADP+ reductase homologous to the chloroplast enzyme and a 38-kDa N-terminal extended form. Small differences in kinetic and catalytic properties were found for these two forms, although the largest one has a 3-fold decreased affinity for ferredoxin. The dissociation rate of reduced ferredoxin from photosystem I (800 s(-1)) and the redox potential of the first reduction of ferredoxin-NADP+ reductase (-380 mV) were determined. In the absence of NADP+, differential absorption spectra support the existence of a high affinity complex between oxidized ferredoxin and semireduced ferredoxin-NADP+ reductase. An effective rate of 140-170 s(-1) was also measured for the second reduction of ferredoxin-NADP+ reductase, this process having a rate constant similar to that of the first reduction. In the presence of NADP+, the second-order rate constant for the first reduction of ferredoxin-NADP+ reductase was 20% slower than in its absence, in line with the existence of ternary complexes (ferredoxin-NADP+ reductase)-NADP+-ferredoxin. A single catalytic turnover was monitored, with 50% NADP+ being reduced in 8-10 ms using 1.6 microM photosystem I. In conditions of multiple turnover, we determined initial rates of 360-410 electrons per s and per ferredox-in-NADP+ reductase for the reoxidation of 3.5 microM photoreduced ferredoxin. Identical rates were found with photosystem I lacking the PsaE subunit and wild type photosystem I. This suggests that, in contrast with previous proposals, the PsaE subunit is not involved in NADP+ photoreduction.
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Affiliation(s)
- Nicolas Cassan
- Service de Bioénergétique and CNRS URA 2096, Département de Biologie Joliot Curie, CEA Saclay, 91191 Gif sur Yvette, France
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47
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Dupuy DLC, Rial DV, Ceccarelli EA. Inhibition of pea ferredoxin-NADP(H) reductase by Zn-ferrocyanide. EUROPEAN JOURNAL OF BIOCHEMISTRY 2004; 271:4582-93. [PMID: 15560800 DOI: 10.1111/j.1432-1033.2004.04430.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Ferredoxin-NADP(H) reductases (FNRs) represent a prototype of enzymes involved in numerous metabolic pathways. We found that pea FNR ferricyanide diaphorase activity was inhibited by Zn2+ (Ki 1.57 microM). Dichlorophenolindophenol diaphorase activity was also inhibited by Zn2+ (Ki 1.80 microM), but the addition of ferrocyanide was required, indicating that the inhibitor is an arrangement of both ions. Escherichia coli FNR was also inhibited by Zn-ferrocyanide, suggesting that inhibition is a consequence of common structural features of these flavoenzymes. The inhibitor behaves in a noncompetitive manner for NADPH and for artificial electron acceptors. Analysis of the oxidation state of the flavin during catalysis in the presence of the inhibitor suggests that the electron-transfer process between NADPH and the flavin is not significantly altered, and that the transfer between the flavin and the second substrate is mainly affected. Zn-ferrocyanide interacts with the reductase, probably increasing the accessibility of the prosthetic group to the solvent. Ferredoxin reduction was also inhibited by Zn-ferrocyanide in a noncompetitive manner, but the observed Ki was about nine times higher than those for the diaphorase reactions. The electron transfer to Anabaena flavodoxin was not affected by Zn-ferrocyanide. Binding of the apoflavodoxin to the reductase was sufficient to overcome the inhibition by Zn-ferrocyanide, suggesting that the interaction of FNRs with their proteinaceous electron partners may induce a conformational change in the reductase that alters or completely prevents the inhibitory effect.
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Affiliation(s)
- Daniela L Catalano Dupuy
- Molecular Biology Division, IBR (Instituto de Biología Molecular y Celular de Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Argentina
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48
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Ceccarelli EA, Arakaki AK, Cortez N, Carrillo N. Functional plasticity and catalytic efficiency in plant and bacterial ferredoxin-NADP(H) reductases. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1698:155-65. [PMID: 15134648 DOI: 10.1016/j.bbapap.2003.12.005] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2003] [Revised: 12/05/2003] [Accepted: 12/10/2003] [Indexed: 11/20/2022]
Abstract
Ferredoxin (flavodoxin)-NADP(H) reductases (FNRs) are ubiquitous flavoenzymes that deliver NADPH or low potential one-electron donors (ferredoxin, flavodoxin, adrenodoxin) to redox-based metabolisms in plastids, mitochondria and bacteria. Two great families of FAD-containing proteins displaying FNR activity have evolved from different and independent origins. The enzymes present in mitochondria and some bacterial genera are members of the structural superfamily of disulfide oxidoreductases whose prototype is glutathione reductase. A second group, comprising the FNRs from plastids and most eubacteria, constitutes a unique family, the plant-type FNRs, totally unrelated in sequence with the former. The two-domain structure of the plant family of FNR also provides the basic scaffold for an extended superfamily of electron transfer flavoproteins. In this article we compare FNR flavoenzymes from very different origins and describe how the natural history of these reductases shaped structure, flavin conformation and catalytic activity to face the very different metabolic demands they have to deal with in their hosts. We show that plant-type FNRs can be classified into a plastidic class, characterised by extended FAD conformation and high catalytic efficiency, and a bacterial class displaying a folded FAD molecule and low turnover rates. Sequence alignments supported this classification, providing a criterion to predict the structural and biochemical properties of newly identified members of the family.
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Affiliation(s)
- Eduardo A Ceccarelli
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina.
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49
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Fernández-Recio J, Totrov M, Abagyan R. Identification of Protein–Protein Interaction Sites from Docking Energy Landscapes. J Mol Biol 2004; 335:843-65. [PMID: 14687579 DOI: 10.1016/j.jmb.2003.10.069] [Citation(s) in RCA: 206] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Protein recognition is one of the most challenging and intriguing problems in structural biology. Despite all the available structural, sequence and biophysical information about protein-protein complexes, the physico-chemical patterns, if any, that make a protein surface likely to be involved in protein-protein interactions, remain elusive. Here, we apply protein docking simulations and analysis of the interaction energy landscapes to identify protein-protein interaction sites. The new protocol for global docking based on multi-start global energy optimization of an all-atom model of the ligand, with detailed receptor potentials and atomic solvation parameters optimized in a training set of 24 complexes, explores the conformational space around the whole receptor without restrictions. The ensembles of the rigid-body docking solutions generated by the simulations were subsequently used to project the docking energy landscapes onto the protein surfaces. We found that highly populated low-energy regions consistently corresponded to actual binding sites. The procedure was validated on a test set of 21 known protein-protein complexes not used in the training set. As much as 81% of the predicted high-propensity patch residues were located correctly in the native interfaces. This approach can guide the design of mutations on the surfaces of proteins, provide geometrical details of a possible interaction, and help to annotate protein surfaces in structural proteomics.
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Affiliation(s)
- Juan Fernández-Recio
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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50
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Tejero J, Martínez-Julvez M, Mayoral T, Luquita A, Sanz-Aparicio J, Hermoso JA, Hurley JK, Tollin G, Gómez-Moreno C, Medina M. Involvement of the pyrophosphate and the 2'-phosphate binding regions of ferredoxin-NADP+ reductase in coenzyme specificity. J Biol Chem 2003; 278:49203-14. [PMID: 14500716 DOI: 10.1074/jbc.m307934200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous studies indicated that the determinants of coenzyme specificity in ferredoxin-NADP+ reductase (FNR) from Anabaena are situated in the 2'-phosphate (2'-P) NADP+ binding region, and also suggested that other regions must undergo structural rearrangements of the protein backbone during coenzyme binding. Among the residues involved in such specificity could be those located in regions where interaction with the pyrophosphate group of the coenzyme takes place, namely loops 155-160 and 261-268 in Anabaena FNR. In order to learn more about the coenzyme specificity determinants, and to better define the structural basis of coenzyme binding, mutations in the pyrophosphate and 2'-P binding regions of FNR have been introduced. Modification of the pyrophosphate binding region, involving residues Thr-155, Ala-160, and Leu-263, indicates that this region is involved in determining coenzyme specificity and that selected alterations of these positions produce FNR enzymes that are able to bind NAD+. Thus, our results suggest that slightly different structural rearrangements of the backbone chain in the pyrophosphate binding region might determine FNR specificity for the coenzyme. Combined mutations at the 2'-P binding region, involving residues Ser-223, Arg-224, Arg-233, and Tyr-235, in combination with the residues mentioned above in the pyrophosphate binding region have also been carried out in an attempt to increase the FNR affinity for NAD+/H. However, in most cases the analyzed mutants lost the ability for NADP+/H binding and electron transfer, and no major improvements were observed with regard to the efficiency of the reactions with NAD+/H. Therefore, our results confirm that determinants for coenzyme specificity in FNR are also situated in the pyrophosphate binding region and not only in the 2'-P binding region. Such observations also suggest that other regions of the protein, yet to be identified, might also be involved in this process.
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Affiliation(s)
- Jesús Tejero
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Madrid, Spain
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