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Cohen A, Hacham Y, Welfe Y, Khatib S, Avice JC, Amir R. Evidence of a significant role of glutathione reductase in the sulfur assimilation pathway. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:246-261. [PMID: 31782847 DOI: 10.1111/tpj.14621] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 10/15/2019] [Accepted: 11/01/2019] [Indexed: 06/10/2023]
Abstract
With the objective of studying the role of glutathione reductase (GR) in the accumulation of cysteine and methionine, we generated transgenic tobacco and Arabidopsis lines overexpressing the cytosolic AtGR1 and the plastidic AtGR2 genes. The transgenic plants had higher contents of cysteine and glutathione. To understand why cysteine levels increased in these plants, we also used gr1 and gr2 mutants. The results showed that the transgenic plants have higher levels of sulfite, cysteine, glutathione and methionine, which are downstream to adenosine 5' phosphosulfate reductase (APR) activity. However, the mutants had lower levels of these metabolites, while the sulfate content increased. A feeding experiment using 34 SO42- also showed that the levels of APR downstream metabolites increased in the transgenic lines and decreased in gr1 compared with their controls. These findings, and the results obtained from the expression levels of several genes related to the sulfur pathway, suggest that GR plays an essential role in the sulfur assimilation pathway by supporting the activity of APR, the key enzyme in this pathway. GR recycles the oxidized form of glutathione (GSSG) back to reduce glutathione (GSH), which serves as an electron donor for APR activity. The phenotypes of the transgenic plants and the mutants are not significantly altered under non-stress and oxidative stress conditions. However, when germinating on sulfur-deficient medium, the transgenic plants grew better, while the mutants were more sensitive than the control plants. The results give substantial evidence of the yet unreported function of GR in the sulfur assimilation pathway.
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Affiliation(s)
- Anner Cohen
- Laboratory of Plant Science, Migal - Galilee Technology Center, Kiryat Shmona, 12100, Israel
- Tel-Hai Collage, Upper Galilee, 11016, Israel
| | - Yael Hacham
- Laboratory of Plant Science, Migal - Galilee Technology Center, Kiryat Shmona, 12100, Israel
- Tel-Hai Collage, Upper Galilee, 11016, Israel
| | - Yochai Welfe
- Laboratory of Plant Science, Migal - Galilee Technology Center, Kiryat Shmona, 12100, Israel
- Tel-Hai Collage, Upper Galilee, 11016, Israel
| | - Soliman Khatib
- Laboratory of Plant Science, Migal - Galilee Technology Center, Kiryat Shmona, 12100, Israel
- Tel-Hai Collage, Upper Galilee, 11016, Israel
| | | | - Rachel Amir
- Laboratory of Plant Science, Migal - Galilee Technology Center, Kiryat Shmona, 12100, Israel
- Tel-Hai Collage, Upper Galilee, 11016, Israel
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Chen FF, Chien CY, Cho CC, Chang YY, Hsu CH. C-terminal Redox Domain of Arabidopsis APR1 is a Non-Canonical Thioredoxin Domain with Glutaredoxin Function. Antioxidants (Basel) 2019; 8:antiox8100461. [PMID: 31597378 PMCID: PMC6827007 DOI: 10.3390/antiox8100461] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/23/2019] [Accepted: 10/03/2019] [Indexed: 01/07/2023] Open
Abstract
Sulfur is an essential nutrient that can be converted into utilizable metabolic forms to produce sulfur-containing metabolites in plant. Adenosine 5'-phosphosulfate (APS) reductase (APR) plays a vital role in catalyzing the reduction of activated sulfate to sulfite, which requires glutathione. Previous studies have shown that the C-terminal domain of APR acts as a glutathione-dependent reductase. The crystal structure of the C-terminal redox domain of Arabidopsis APR1 (AtAPR1) shows a conserved α/β thioredoxin fold, but not a glutaredoxin fold. Further biochemical studies of the redox domain from AtAPR1 provided evidence to support the structural observation. Collectively, our results provide structural and biochemical information to explain how the thioredoxin fold exerts the glutaredoxin function in APR.
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Affiliation(s)
- Fang-Fang Chen
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan, (F.-F.C.); (C.-Y.C.); (Y.-Y.C.)
| | - Chia-Yu Chien
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan, (F.-F.C.); (C.-Y.C.); (Y.-Y.C.)
| | - Chao-Cheng Cho
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan;
| | - Yu-Yung Chang
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan, (F.-F.C.); (C.-Y.C.); (Y.-Y.C.)
| | - Chun-Hua Hsu
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan, (F.-F.C.); (C.-Y.C.); (Y.-Y.C.)
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan;
- Correspondence: ; Tel.: +886-2-33664468
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Jez JM. Structural biology of plant sulfur metabolism: from sulfate to glutathione. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:4089-4103. [PMID: 30825314 DOI: 10.1093/jxb/erz094] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 02/12/2019] [Indexed: 06/09/2023]
Abstract
Sulfur is an essential element for all organisms. Plants must assimilate this nutrient from the environment and convert it into metabolically useful forms for the biosynthesis of a wide range of compounds, including cysteine and glutathione. This review summarizes structural biology studies on the enzymes involved in plant sulfur assimilation [ATP sulfurylase, adenosine-5'-phosphate (APS) reductase, and sulfite reductase], cysteine biosynthesis (serine acetyltransferase and O-acetylserine sulfhydrylase), and glutathione biosynthesis (glutamate-cysteine ligase and glutathione synthetase) pathways. Overall, X-ray crystal structures of enzymes in these core pathways provide molecular-level information on the chemical events that allow plants to incorporate sulfur into essential metabolites and revealed new biochemical regulatory mechanisms, such as structural rearrangements, protein-protein interactions, and thiol-based redox switches, for controlling different steps in these pathways.
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Affiliation(s)
- Joseph M Jez
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
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Xiang X, Pan G, Rong T, Zheng ZL, Leustek T. A luciferase-based method for assay of 5'-adenylylsulfate reductase. Anal Biochem 2014; 460:22-8. [PMID: 24857786 DOI: 10.1016/j.ab.2014.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/13/2014] [Accepted: 05/14/2014] [Indexed: 01/13/2023]
Abstract
A luciferase-based method was developed for measurement of 5'-adenylylsulfate (APS) reductase (APR), an enzyme of the reductive sulfate assimilation pathway in prokaryotes and plants. APR catalyzes the two-electron reduction of APS and forms sulfite and adenosine 5'-monophospahate (AMP). The luciferase-based assay measures AMP production using an enzyme-coupled system that generates luminescence. The method is shown to provide an accurate measurement of APR kinetic properties and can be used for both endpoint and continuous assays. APR activity can be measured from pure enzyme preparations as well as from crude protein extracts of tissues. In addition, the assay is ideally suited to high-throughput sample analysis of APR activity in a microtiter dish format. The method adds new capability to the study of the biochemistry and physiology of APR.
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Affiliation(s)
- Xiaoli Xiang
- Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ 08901, USA; Institute of Maize Research, Key Laboratory of Biology and Genetic Improvement of Maize in the Southwest Region, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, China
| | - Guangtang Pan
- Institute of Maize Research, Key Laboratory of Biology and Genetic Improvement of Maize in the Southwest Region, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, China
| | - Tingzhao Rong
- Institute of Maize Research, Key Laboratory of Biology and Genetic Improvement of Maize in the Southwest Region, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, China
| | - Zhi-Liang Zheng
- Department of Biological Sciences, Lehman College, City University of New York, Bronx, NY 10468, USA
| | - Thomas Leustek
- Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ 08901, USA.
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Brychkova G, Yarmolinsky D, Sagi M. Kinetic assays for determining in vitro APS reductase activity in plants without the use of radioactive substances. PLANT & CELL PHYSIOLOGY 2012; 53:1648-58. [PMID: 22833665 DOI: 10.1093/pcp/pcs091] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Adenosine 5'-phosphosulfate (APS) reductase (APR; EC 1.8.4.9) catalyzes the two-electron reduction of APS to sulfite and AMP, a key step in the sulfate assimilation pathway in higher plants. In spite of the importance of this enzyme, methods currently available for detection of APR activity rely on radioactive labeling and can only be performed in a very few specially equipped laboratories. Here we present two novel kinetic assays for detecting in vitro APR activity that do not require radioactive labeling. In the first assay, APS is used as substrate and reduced glutathione (GSH) as electron donor, while in the second assay APS is replaced by an APS-regenerating system in which ATP sulfurylase catalyzes APS in the reaction medium, which employs sulfate and ATP as substrates. Both kinetic assays rely on fuchsin colorimetric detection of sulfite, the final product of APR activity. Incubation of the desalted protein extract, prior to assay initiation, with tungstate that inhibits the oxidation of sulfite by sulfite oxidase activity, resulted in enhancement of the actual APR activity. The reliability of the two methods was confirmed by assaying leaf extract from Arabidopsis wild-type and APR mutants with impaired or overexpressed APR2 protein, the former lacking APR activity and the latter exhibiting much higher activity than the wild type. The assays were further tested on tomato leaves, which revealed a higher APR activity than Arabidopsis. The proposed APR assays are highly specific, technically simple and readily performed in any laboratory.
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Affiliation(s)
- Galina Brychkova
- Plant Stress Laboratory, The Albert Katz Department of Dryland Biotechnologies, French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of Negev, Sede Boqer Campus 84990, Israel
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Bhave DP, Hong JA, Keller RL, Krebs C, Carroll KS. Iron-sulfur cluster engineering provides insight into the evolution of substrate specificity among sulfonucleotide reductases. ACS Chem Biol 2012; 7:306-15. [PMID: 22023093 PMCID: PMC3288176 DOI: 10.1021/cb200261n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Assimilatory sulfate reduction supplies prototrophic organisms with reduced sulfur that is required for the biosynthesis of all sulfur-containing metabolites, including cysteine and methionine. The reduction of sulfate requires its activation via an ATP-dependent activation to form adenosine-5'-phosphosulfate (APS). Depending on the species, APS can be reduced directly to sulfite by APS reductase (APR) or undergo a second phosphorylation to yield 3'-phosphoadenosine-5'-phosphosulfate (PAPS), the substrate for PAPS reductase (PAPR). These essential enzymes have no human homologue, rendering them attractive targets for the development of novel antibacterial drugs. APR and PAPR share sequence and structure homology as well as a common catalytic mechanism, but the enzymes are distinguished by two features, namely, the amino acid sequence of the phosphate-binding loop (P-loop) and an iron-sulfur cofactor in APRs. On the basis of the crystal structures of APR and PAPR, two P-loop residues are proposed to determine substrate specificity; however, this hypothesis has not been tested. In contrast to this prevailing view, we report here that the P-loop motif has a modest effect on substrate discrimination. Instead, by means of metalloprotein engineering, spectroscopic, and kinetic analyses, we demonstrate that the iron-sulfur cluster cofactor enhances APS reduction by nearly 1000-fold, thereby playing a pivotal role in substrate specificity and catalysis. These findings offer new insights into the evolution of this enzyme family and extend the known functions of protein-bound iron-sulfur clusters.
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Affiliation(s)
- Devayani P. Bhave
- Chemical Biology Graduate Program, University of Michigan, Ann Arbor, Michigan, 48109-2216
| | - Jiyoung A. Hong
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, 48109-2216
| | - Rebecca L. Keller
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Carsten Krebs
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Kate S. Carroll
- Chemical Biology Graduate Program, University of Michigan, Ann Arbor, Michigan, 48109-2216
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, 48109-2216
- Department of Chemistry, The Scripps Research Institute, Jupiter, Florida 33458
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Lee JS, White E, Kim SG, Schlesinger SR, Lee SY, Kim SK. Discovery of a novel adenosine 5′-phosphosulfate (APS) reductase from the methanarcheon Methanocaldococcus jannaschii. Process Biochem 2011. [DOI: 10.1016/j.procbio.2010.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Kim SG, Chi YH, Lee JS, Schlesinger SR, Zabet-Moghaddam M, Chung JS, Knaff DB, Kim ST, Lee SY, Kim SK. Redox properties of a thioredoxin-like Arabidopsis protein, AtTDX. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:2213-21. [DOI: 10.1016/j.bbapap.2010.09.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/19/2010] [Accepted: 09/07/2010] [Indexed: 01/05/2023]
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Yu Z, Lemongello D, Segel IH, Fisher AJ. Crystal structure of Saccharomyces cerevisiae 3'-phosphoadenosine-5'-phosphosulfate reductase complexed with adenosine 3',5'-bisphosphate. Biochemistry 2009; 47:12777-86. [PMID: 18991405 DOI: 10.1021/bi801118f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Most assimilatory bacteria, fungi, and plants species reduce sulfate (in the activated form of APS or PAPS) to produce reduced sulfur. In yeast, PAPS reductase reduces PAPS to sulfite and PAP. Despite the difference in substrate specificity and catalytic cofactor, PAPS reductase is homologous to APS reductase in both sequence and structure, and they are suggested to share the same catalytic mechanism. Metazoans do not possess the sulfate reduction pathway, which makes APS/PAPS reductases potential drug targets for human pathogens. Here, we present the 2.05 A resolution crystal structure of the yeast PAPS reductase binary complex with product PAP bound. The N-terminal region mediates dimeric interactions resulting in a unique homodimer assembly not seen in previous APS/PAPS reductase structures. The "pyrophosphate-binding" sequence (47)TTAFGLTG(54) defines the substrate 3'-phosphate binding pocket. In yeast, Gly54 replaces a conserved aspartate found in APS reductases vacating space and charge to accommodate the 3'-phosphate of PAPS, thus regulating substrate specificity. Also, for the first time, the complete C-terminal catalytic motif (244)ECGIH(248) is revealed in the active site. The catalytic residue Cys245 is ideally positioned for an in-line attack on the beta-sulfate of PAPS. In addition, the side chain of His248 is only 4.2 A from the Sgamma of Cys245 and may serve as a catalytic base to deprotonate the active site cysteine. A hydrophobic sequence (252)RFAQFL(257) at the end of the C-terminus may provide anchoring interactions preventing the tail from swinging away from the active site as seen in other APS/PAPS reductases.
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Affiliation(s)
- Zhihao Yu
- Departments of Chemistry and Molecular and Cellular Biology, University of California, Davis, One Shields Avenue, Davis, California 95616
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Kopriva S, Fritzemeier K, Wiedemann G, Reski R. The putative moss 3'-phosphoadenosine-5'-phosphosulfate reductase is a novel form of adenosine-5'-phosphosulfate reductase without an iron-sulfur cluster. J Biol Chem 2007; 282:22930-8. [PMID: 17519237 DOI: 10.1074/jbc.m702522200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sulfate assimilation provides reduced sulfur for synthesis of the amino acids cysteine and methionine and for a range of other metabolites. Sulfate has to be activated prior to reduction by adenylation to adenosine 5'-phosphosulfate (APS). In plants, algae, and many bacteria, this compound is reduced to sulfite by APS reductase (APR); in fungi and some cyanobacteria and gamma-proteobacteria, a second activation step, phosphorylation to 3'-phosphoadenosine 5'-phosphosulfate (PAPS), is necessary before reduction to sulfite by PAPS reductase (PAPR). We found previously that the moss Physcomitrella patens is unique among these organisms in possessing orthologs of both APR and PAPR genes (Koprivova, A., Meyer, A. J., Schween, G., Herschbach, C., Reski, R., and Kopriva, S. (2002) J. Biol. Chem. 277, 32195-32201). To assess the function of the two enzymes, we compared their biochemical properties by analysis of purified recombinant proteins. APR from Physcomitrella is very similar to the well characterized APRs from seed plants. On the other hand, we found that the putative PAPR preferentially reduces APS. Sequence analysis, analysis of UV-visible spectra, and determination of iron revealed that this new APR, named PpAPR-B, does not contain the FeS cluster, which was previously believed to determine the substrate specificity of the otherwise relatively similar enzymes. The lack of the FeS cluster in PpAPR-B catalysis is connected with a lower turnover rate but higher stability of the protein. These findings show that APS reduction without the FeS cluster is possible and that plant sulfate assimilation is predominantly dependent on reduction of APS.
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Affiliation(s)
- Stanislav Kopriva
- Department of Metabolic Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
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