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Akkermans V, Verstraete R, Braem C, D'aes J, Dries J. Mannosylerythritol Lipid Production from Oleaginous Yeast Cell Lysate byMoesziomyces aphidis. Ind Biotechnol (New Rochelle N Y) 2020. [DOI: 10.1089/ind.2019.0040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Veerle Akkermans
- Faculty of Applied Engineering, University of Antwerp, Antwerpen, Belgium
| | - Ruben Verstraete
- Faculty of Applied Engineering, University of Antwerp, Antwerpen, Belgium
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Belgium
| | - Caroline Braem
- Department of Industrial Sciences and Technology, Karel de Grote University College, Hoboken, Belgium
| | - Jolien D'aes
- Faculty of Applied Engineering, University of Antwerp, Antwerpen, Belgium
| | - Jan Dries
- Faculty of Applied Engineering, University of Antwerp, Antwerpen, Belgium
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Lin D, Huang Y, Zhao J, Wu Z, Liu S, Qin W, Wu D, Chen H, Zhang Q. Evaluation of seed nitrate assimilation and stimulation of phenolic-linked antioxidant on pentose phosphate pathway and nitrate reduction in three feed-plant species. BMC PLANT BIOLOGY 2020; 20:267. [PMID: 32517649 PMCID: PMC7285455 DOI: 10.1186/s12870-020-02453-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 05/20/2020] [Indexed: 05/23/2023]
Abstract
BACKGROUND Soil and water pollution due to nitrate are becoming increasingly serious worldwide. The government also put forward relevant governance policies, and a large number of scholars studied chemical physics and other methods to remove nitrate in water, but the cost was substantial. Studies have found that planting systems including grasses have the potential to remove nitrates. However, there are few studies on nitrate linked pathway and nitrate assimilation during its early growth. RESULTS We have evaluated three different feed-plant species with three levels of overnight seed nitrate treatments along with a control. The activity of different enzymes from 2 weeks old shoots was measured to get a comprehension of proline-associated pentose phosphate pathway coupled with nitrate assimilation and phenolic-linked antioxidant response system in these species under nitrate treatments. All three feed-plant species showed high nitrate tolerance during germination and early growth stages. It is perceived that the accumulation of total soluble phenolics and total antioxidant activity was high in all three feed-plant species under high nitrate treatments. In terms of high G6PDH activity along with low SDH activity in alfalfa, there may be a shift of carbon flux in this species under high nitrate treatments. Higher activity of these enzymes along with higher SOD and GPX activity was observed in alfalfa. The efficient mechanism of nitrate stress tolerance of alfalfa also correlated with higher photochemical efficiency. Perennial ryegrass also showed excellent potential under high nitrate treatments by adopting an efficient mechanism to counter nitrate-induced oxidative stress. CONCLUSIONS Under the condition of nitrate treatment, the germination rates of the three feed-plant species are still ideal, and they have good enzyme activity and have the potential to remove nitrate.
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Affiliation(s)
- Derong Lin
- School of Food Science, Sichuan Agricultural University, Ya’an, 625014 China
| | - Yichen Huang
- School of Food Science, Sichuan Agricultural University, Ya’an, 625014 China
| | - Jingjing Zhao
- School of Food Science, Sichuan Agricultural University, Ya’an, 625014 China
| | - Zhijun Wu
- College of Mechanical and Electrical Engineering, Sichuan Agricultural University, Ya’an, 625014 China
| | - Shuliang Liu
- School of Food Science, Sichuan Agricultural University, Ya’an, 625014 China
| | - Wen Qin
- School of Food Science, Sichuan Agricultural University, Ya’an, 625014 China
| | - Dingtao Wu
- School of Food Science, Sichuan Agricultural University, Ya’an, 625014 China
| | - Hong Chen
- School of Food Science, Sichuan Agricultural University, Ya’an, 625014 China
| | - Qing Zhang
- School of Food Science, Sichuan Agricultural University, Ya’an, 625014 China
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Yeh Martín N, Valer L, Mansy SS. Toward long-lasting artificial cells that better mimic natural living cells. Emerg Top Life Sci 2019; 3:597-607. [PMID: 33523164 PMCID: PMC7288992 DOI: 10.1042/etls20190026] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/09/2019] [Accepted: 08/13/2019] [Indexed: 01/01/2023]
Abstract
Chemical communication is ubiquitous in biology, and so efforts in building convincing cellular mimics must consider how cells behave on a population level. Simple model systems have been built in the laboratory that show communication between different artificial cells and artificial cells with natural, living cells. Examples include artificial cells that depend on purely abiological components and artificial cells built from biological components and are driven by biological mechanisms. However, an artificial cell solely built to communicate chemically without carrying the machinery needed for self-preservation cannot remain active for long periods of time. What is needed is to begin integrating the pathways required for chemical communication with metabolic-like chemistry so that robust artificial systems can be built that better inform biology and aid in the generation of new technologies.
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Affiliation(s)
- Noël Yeh Martín
- Systems Biophysics, Physics Department, Ludwig-Maximilians-Universität München, Amalienstraße 54, 80799 München, Germany
| | - Luca Valer
- Department CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
| | - Sheref S Mansy
- Department CIBIO, University of Trento, via Sommarive 9, 38123 Povo, Italy
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB, Canada T6G 2G2
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Sanz-Luque E, Chamizo-Ampudia A, Llamas A, Galvan A, Fernandez E. Understanding nitrate assimilation and its regulation in microalgae. FRONTIERS IN PLANT SCIENCE 2015; 6:899. [PMID: 26579149 PMCID: PMC4620153 DOI: 10.3389/fpls.2015.00899] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/09/2015] [Indexed: 05/02/2023]
Abstract
Nitrate assimilation is a key process for nitrogen (N) acquisition in green microalgae. Among Chlorophyte algae, Chlamydomonas reinhardtii has resulted to be a good model system to unravel important facts of this process, and has provided important insights for agriculturally relevant plants. In this work, the recent findings on nitrate transport, nitrate reduction and the regulation of nitrate assimilation are presented in this and several other algae. Latest data have shown nitric oxide (NO) as an important signal molecule in the transcriptional and posttranslational regulation of nitrate reductase and inorganic N transport. Participation of regulatory genes and proteins in positive and negative signaling of the pathway and the mechanisms involved in the regulation of nitrate assimilation, as well as those involved in Molybdenum cofactor synthesis required to nitrate assimilation, are critically reviewed.
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Affiliation(s)
| | | | | | | | - Emilio Fernandez
- Department of Biochemistry and Molecular Biology, University of CordobaCordoba, Spain
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Yoneyama T, Fujimori T, Yanagisawa S, Hase T, Suzuki A. 15N Tracing Studies on In Vitro Reactions of Ferredoxin-Dependent Nitrite Reductase and Glutamate Synthase Using Reconstituted Electron Donation Systems. PLANT & CELL PHYSIOLOGY 2015; 56:1154-1161. [PMID: 25745028 DOI: 10.1093/pcp/pcv039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 02/24/2015] [Indexed: 06/04/2023]
Abstract
It is known that plants contain ferredoxin (Fd)-dependent nitrite reductase (NiR) and glutamate synthase (GOGAT). The Fd-NiR reaction produces ammonia from nitrite, and the activity is usually measured by nitrite disappearance. The Fd-GOGAT reaction forms two glutamates of different origin, from glutamine and 2-oxoglutarate, and the activity is measured by the oxidation of reductant (NADPH) or by formation of total glutamate. Here, a quantitative probe of the products and efficiency of the process was conducted using (15)N tracing techniques on these reactions in vitro. We quantified the reduction of (15)N-labeled [Formula: see text] to [Formula: see text] and the formation of [(15)N]glutamate and [(14)N]glutamate from [5-(15)N-amide]glutamine plus 2-oxoglutarate by NiR and GOGAT, respectively, with the reductant-Fd-NADP(+) oxidoreductase (FNR)-Fd system as the sequential electron donors. The supply of dithionite or NADPH to recombinant cyanobacterial NiR led to electron donation system-dependent formation of [(15)N]ammonium from [(15)N]nitrite. Addition of 20 mM NaCl and 20 mM Na-ascorbate accelerated nitrite reduction under high concentrations of NADPH. A sufficient supply of NADPH to recombinant Zea mays Fd-GOGAT generated complete GOGAT activity (transferring the [5-(15)N]amide of glutamine to 2-oxoglutarate to form [(15)N]glutamate), whereas a shortage of NADPH resulted in glutaminase activity only, which removed the amide from glutamine and released ammonia and [(14)N]glutamate. We conclude that although the recombinant Fd-GOGAT enzyme has two forms of glutamate synthesis, the first by glutaminase (ammonia release by glutamine amidotransferase) and the second by glutamate synthase (coupling of the ammonia and exogenously applied 2-oxoglutarate), the first works without NADPH, while the second is strictly dependent on NADPH availability.
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Affiliation(s)
- Tadakatsu Yoneyama
- Department of Applied Biological Chemistry, the University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Tamaki Fujimori
- Department of Applied Biological Chemistry, the University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Shuichi Yanagisawa
- Department of Applied Biological Chemistry, the University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Toshiharu Hase
- Laboratory of Regulation of Biological Reaction, Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871 Japan
| | - Akira Suzuki
- INRA, Institut Jean-Pierre Bourgin, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
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Sanz-Luque E, Ocaña-Calahorro F, Llamas A, Galvan A, Fernandez E. Nitric oxide controls nitrate and ammonium assimilation in Chlamydomonas reinhardtii. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:3373-83. [PMID: 23918969 DOI: 10.1093/jxb/ert175] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Nitrate and ammonium are major inorganic nitrogen sources for plants and algae. These compounds are assimilated by means of finely regulated processes at transcriptional and post-translational levels. In Chlamydomonas, the expression of several genes involved in high-affinity ammonium (AMT1.1, AMT1.2) and nitrate transport (NRT2.1) as well as nitrate reduction (NIA1) are downregulated by ammonium through a nitric oxide (NO)-dependent mechanism. At the post-translational level, nitrate/nitrite uptake and nitrate reductase (NR) are also inhibited by ammonium, but the mechanisms implicated in this regulation are scarcely known. In this work, the effect of NO on nitrate assimilation and the high-affinity ammonium uptake was addressed. NO inhibited the high-affinity uptake of ammonium and nitrate/nitrite, as well as the NR activity, in a reversible form. In contrast, nitrite reductase and glutamine synthetase activities were not affected. The in vivo and in vitro studies suggested that NR enzyme is inhibited by NO in a mediated process that requires the cell integrity. These data highlight a role of NO in inorganic nitrogen assimilation and suggest that this signalling molecule is an important regulator for the first steps of the pathway.
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Affiliation(s)
- Emanuel Sanz-Luque
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Campus de Excelencia Agroalimentario CeiA3, Campus de Rabanales, Edificio Severo Ochoa, Córdoba 14071, Spain
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Purification and biochemical characterisation of a glucose-6-phosphate dehydrogenase from the psychrophilic green alga Koliella antarctica. Extremophiles 2012; 17:53-62. [DOI: 10.1007/s00792-012-0492-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 10/18/2012] [Indexed: 10/27/2022]
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Valadier MH, Yoshida A, Grandjean O, Morin H, Kronenberger J, Boutet S, Raballand A, Hase T, Yoneyama T, Suzuki A. Implication of the glutamine synthetase/glutamate synthase pathway in conditioning the amino acid metabolism in bundle sheath and mesophyll cells of maize leaves. FEBS J 2008; 275:3193-206. [DOI: 10.1111/j.1742-4658.2008.06472.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wakao S, Andre C, Benning C. Functional analyses of cytosolic glucose-6-phosphate dehydrogenases and their contribution to seed oil accumulation in Arabidopsis. PLANT PHYSIOLOGY 2008; 146:277-88. [PMID: 17993547 PMCID: PMC2230552 DOI: 10.1104/pp.107.108423] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Accepted: 11/05/2007] [Indexed: 05/18/2023]
Abstract
Glucose-6-phosphate dehydrogenase (G6PDH) has been implicated in the supply of reduced nicotine amide cofactors for biochemical reactions and in modulating the redox state of cells. In plants, identification of its role is complicated due to the presence of several isoforms in the cytosol and plastids. Here we focus on G6PDHs in the cytosol of Arabidopsis (Arabidopsis thaliana) using single and double mutants disrupted in the two cytosolic G6PDHs. Only a single G6PDH isoform remained in the double mutant and was present in chloroplasts, consistent with a loss of cytosolic G6PDH activity. The activities of the cytosolic isoforms G6PD5 and G6PD6 were reciprocally increased in single mutants with no increase of their respective transcript levels. We hypothesized that G6PDH plays a role in supplying NADPH for oil accumulation in developing seeds in which photosynthesis may be light limited. G6PDH activity in seeds derived from G6PD6 and a plastid G6PDH isoform and showed a similar temporal activity pattern as oil accumulation. Seeds of the double mutant but not of the single mutants had higher oil content and increased weight compared to those of the wild type, with no alteration in the carbon to nitrogen ratio or fatty acid composition. A decrease in total G6PDH activity was observed only in the double mutant. These results suggest that loss of cytosolic G6PDH activity affects the metabolism of developing seeds by increasing carbon substrates for synthesis of storage compounds rather than by decreasing the NADPH supply specifically for fatty acid synthesis.
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Affiliation(s)
- Setsuko Wakao
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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Esposito S, Guerriero G, Vona V, Di Martino Rigano V, Carfagna S, Rigano C. Glucose-6P dehydrogenase in Chlorella sorokiniana (211/8k): an enzyme with unusual characteristics. PLANTA 2006; 223:796-804. [PMID: 16160846 DOI: 10.1007/s00425-005-0110-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Accepted: 07/27/2005] [Indexed: 05/04/2023]
Abstract
In Chlorella sorokiniana (211/8k), glucose-6 phosphate dehydrogenase (G6PDH-EC 1.1.1.49) activity is similar in both N-starved cells and nitrate-grown algae when expressed on a PCV basis. A single G6PDH isoform was purified from Chlorella cells grown under different nutrient conditions; the presence of a single G6PDH was confirmed by native gels stained for enzyme activity and by Western blots. The algal G6PDH is recognised only by antibodies raised against higher plants plastidic protein, but not by chloroplastic and cytosolic isoform-specific antisera. Purified G6PDH showed kinetic parameters similar to plastidic isoforms of higher plants, suggesting a different biochemical structure which would confer peculiar regulative properties to the algal G6PDH with respect to higher plants enzymes. The most remarkable property of algal G6PDH is represented by the response to NADPH inhibition. The algal enzyme is less sensitive to NADPH effects compared to higher plants G6PDH: Ki(NADPH) is 103 microM for G6PDH from nitrogen-starved C. sorokiniana, similarly to root plastidic P2-G6PDH. In nitrate-grown C. sorokiniana the Ki(NADPH) decreased to 48 microM, whereas other kinetic parameters remained unchanged. These results will allow further investigations in order to rule out possible modifications of the enzyme, and/or the expression of a different G6PDH isoform during nitrate assimilation.
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Affiliation(s)
- Sergio Esposito
- Dipartimento delle Scienze Biologiche-Sez. Biologia Vegetale, Università di Napoli Federico II, Italy.
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Hauschild R, von Schaewen A. Differential regulation of glucose-6-phosphate dehydrogenase isoenzyme activities in potato. PLANT PHYSIOLOGY 2003; 133:47-62. [PMID: 12970474 PMCID: PMC196576 DOI: 10.1104/pp.103.025676] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2003] [Revised: 04/23/2003] [Accepted: 05/05/2003] [Indexed: 05/18/2023]
Abstract
In plants, Glc-6-phosphate dehydrogenase (G6PDH) isoenzymes are present in the cytosol and in plastids. The plastidic enzymes (P1 and P2) are subject to redox regulation, but mechanisms that adjust cytosolic G6PDH activity are largely unknown. We adopted a leaf disc system for monitoring the effects of various conditions on G6PD isoform expression and enzyme activities in potato (Solanum tuberosum). Cytosolic G6PDH activity remained constant during water incubation in the dark. In continuous light or in the presence of metabolizable sugars in the dark, cytosolic G6PDH activity increased 6-fold within 24 h. Cycloheximide incubation demonstrated that enhanced cytosolic G6PDH activity depends on de novo protein synthesis. Osmotic change, phosphate sequestration, or oxidative stress did not affect cytosolic G6PDH activity. Furthermore, enzyme activity and protein contents closely followed the corresponding mRNA levels. Together with the fact that multiple SURE elements are present in the promoter region of the gene, these results suggest that cytosolic G6PDH activity is regulated by sugar availability at the transcriptional level. Plastidic G6PDH activity stayed constant during water incubation in the light and dropped to minimal levels within 6 h in the dark. Conversely, plastidic G6PDH activity of leaf discs incubated on Paraquat rose to 10-fold higher levels, which was not prevented by cycloheximide. Similar increases were found with nitrite, nitrate, or sulfate. No major changes in protein or mRNA contents of the plastidic P1 and P2 isoforms were registered. K(m) (Glc-6-phosphate) values of plastidic G6PDH activity differed between samples incubated on water or Paraquat, suggesting posttranslational modification of the plastidic enzyme(s). Immunoprecipitation of (32)P-labeled samples with P1 isoform-specific antibodies showed that the chloroplast enzyme is subject to protein phosphorylation. Obviously, in extended dark periods, G6PDH activity in the stroma is restricted but can be stimulated in response to high demands for NADPH.
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Affiliation(s)
- Rüdiger Hauschild
- Pflanzenphysiologie, FB5 Biologie/Chemie, Universität Osnabrück, Barbarastrasse 11, 49076 Osnabrück, Germany
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Grossman A, Takahashi H. MACRONUTRIENT UTILIZATION BY PHOTOSYNTHETIC EUKARYOTES AND THE FABRIC OF INTERACTIONS. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:163-210. [PMID: 11337396 DOI: 10.1146/annurev.arplant.52.1.163] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Organisms acclimate to a continually fluctuating nutrient environment. Acclimation involves responses specific for the limiting nutrient as well as responses that are more general and occur when an organism experiences different stress conditions. Specific responses enable organisms to efficiently scavenge the limiting nutrient and may involve the induction of high-affinity transport systems and the synthesis of hydrolytic enzymes that facilitate the release of the nutrient from extracellular organic molecules or from internal reserves. General responses include changes in cell division rates and global alterations in metabolic activities. In photosynthetic organisms there must be precise regulation of photosynthetic activity since when severe nutrient limitation prevents continued cell growth, excitation of photosynthetic pigments could result in the formation of reactive oxygen species, which can severely damage structural and functional features of the cell. This review focuses on ways that photosynthetic eukaryotes assimilate the macronutrients nitrogen, sulfur, and phosphorus, and the mechanisms that govern assimilatory activities. Also discussed are molecular responses to macronutrient limitation and the elicitation of those responses through integration of environmental and cellular cues.
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Affiliation(s)
- Arthur Grossman
- Department of Plant Biology, The Carnegie Institution of Washington 260 Panama Street, Stanford, California 94305; e-mail: , RIKEN Plant Science Center, 2-l Hirosawa, Wako, Saitama, 351-0198, Japan; e-mail:
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Onda Y, Matsumura T, Kimata-Ariga Y, Sakakibara H, Sugiyama T, Hase T. Differential interaction of maize root ferredoxin:NADP(+) oxidoreductase with photosynthetic and non-photosynthetic ferredoxin isoproteins. PLANT PHYSIOLOGY 2000; 123:1037-45. [PMID: 10889253 PMCID: PMC59067 DOI: 10.1104/pp.123.3.1037] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/1999] [Accepted: 03/27/2000] [Indexed: 05/20/2023]
Abstract
In higher plants ferredoxin (Fd):NADP(+) oxidoreductase (FNR) and Fd are each distributed in photosynthetic and non-photosynthetic organs as distinct isoproteins. We have cloned cDNAs for leaf FNR (L-FNR I and L-FNR II) and root FNR (R-FNR) from maize (Zea mays L.), and produced recombinant L-FNR I and R-FNR to study their enzymatic functions through kinetic and Fd-binding analyses. The K(m) value obtained by assay for a diaphorase activity indicated that R-FNR had a 10-fold higher affinity for NADPH than L-FNR I. When we assayed for NADPH-cytochrome c reductase activity using maize photosynthetic Fd (Fd I) and non-photosynthetic Fd (Fd III), the R-FNR showed a marked difference in affinity between these two Fd isoproteins; the K(m) for Fd III was 3.0 microM and that for Fd I was 29 microM. Consistent with this, the dissociation constant for the R-FNR:Fd III complex was 10-fold smaller than that of the R-FNR:Fd I complex. This differential binding capacity was confirmed by an affinity chromatography of R-FNR on Fd-sepharose with stronger binding to Fd III. L-FNR I showed no such differential interaction with Fd I and Fd III. These data demonstrated that R-FNR has the ability to discriminate between these two types of Fds. We propose that the stronger interaction of R-FNR with Fd III is crucial for an efficient electron flux of NADPH-FNR-Fd cascade, thus supporting Fd-dependent metabolism in non-photosynthetic organs.
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Affiliation(s)
- Y Onda
- Division of Enzymology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871 Japan
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Yonekura-Sakakibara K, Onda Y, Ashikari T, Tanaka Y, Kusumi T, Hase T. Analysis of reductant supply systems for ferredoxin-dependent sulfite reductase in photosynthetic and nonphotosynthetic organs of maize. PLANT PHYSIOLOGY 2000; 122:887-94. [PMID: 10712553 PMCID: PMC58925 DOI: 10.1104/pp.122.3.887] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/1999] [Accepted: 12/02/1999] [Indexed: 05/20/2023]
Abstract
Sulfite reductase (SiR) catalyzes the reduction of sulfite to sulfide in chloroplasts and root plastids using ferredoxin (Fd) as an electron donor. Using purified maize (Zea mays L.) SiR and isoproteins of Fd and Fd-NADP(+) reductase (FNR), we reconstituted illuminated thylakoid membrane- and NADPH-dependent sulfite reduction systems. Fd I and L-FNR were distributed in leaves and Fd III and R-FNR in roots. The stromal concentrations of SiR and Fd I were estimated at 1.2 and 37 microM, respectively. The molar ratio of Fd III to SiR in root plastids was approximately 3:1. Photoreduced Fd I and Fd III showed a comparable ability to donate electrons to SiR. In contrast, when being reduced with NADPH via FNRs, Fd III showed a several-fold higher activity than Fd I. Fd III and R-FNR showed the highest rate of sulfite reduction among all combinations tested. NADP(+) decreased the rate of sulfite reduction in a dose-dependent manner. These results demonstrate that the participation of Fd III and high NADPH/NADP(+) ratio are crucial for non-photosynthetic sulfite reduction. In accordance with this view, a cysteine-auxotrophic Escherichia coli mutant defective for NADPH-dependent SiR was rescued by co-expression of maize SiR with Fd III but not with Fd I.
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Affiliation(s)
- K Yonekura-Sakakibara
- Institute for Fundamental Research, Suntory Ltd., Wakayamadai, Shimamoto, Mishima, Osaka, 618-8503 Japan.
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