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Li Y, Zheng X, Zhu M, Chen M, Zhang S, He F, Chen X, Lv J, Pei M, Zhang Y, Zhang Y, Wang W, Zhang J, Wang M, Wang Z, Li G, Lu G. MoIVD-Mediated Leucine Catabolism Is Required for Vegetative Growth, Conidiation and Full Virulence of the Rice Blast Fungus Magnaporthe oryzae. Front Microbiol 2019; 10:444. [PMID: 30923517 PMCID: PMC6426774 DOI: 10.3389/fmicb.2019.00444] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 02/20/2019] [Indexed: 01/03/2023] Open
Abstract
Isovaleryl-CoA dehydrogenase (IVD), a member of the acyl-CoA dehydrogenase (ACAD) family, is a key enzyme catalyzing the conversion of isovaleryl-CoA to β-methylcrotonyl-CoA in the third reaction of the leucine catabolism pathway and simultaneously transfers electrons to the electron-transferring flavoprotein (ETF) for ATP synthesis. We previously identified the ETF ortholog in rice blast fungus Magnaporthe oryzae (MoETF) and showed that MoETF was essential for fungal growth, conidiation and pathogenicity. To further investigate the biological function of electron-transferring proteins and clarify the role of leucine catabolism in growth and pathogenesis, we characterized MoIVD (M. oryzaeisovaleryl-CoA dehydrogenase). MoIvd is highly conserved in fungi and its expression was highly induced by leucine. The Δmoivd mutants showed reduced growth, decreased conidiation and compromised pathogenicity, while the conidial germination and appressorial formation appeared normal. Consistent with a block in leucine degradation, the Δmoivd mutants accumulated isovaleric acid, grew more slowly, fully lacked pigmentation and completely failed to produce conidia on leucine-rich medium. These defects were largely rescued by raising the extracellular pH, suggesting that the accumulation of isovaleric acid contributes to the growth and conidiation defects. However, the reduced virulence of the mutants was probably due to their inability to overcome oxidative stress, since a large amount of ROS (reactive oxygen species) accumulated in infected host cell. In addition, MoIvd is localized to mitochondria and interacted with its electron receptor MoEtfb, the β subunit of MoEtf. Taken together, our results suggest that MoIVD functions in leucine catabolism and is required for the vegetative growth, conidiation and full virulence of M. oryzae, providing the first evidence for IVD-mediated leucine catabolism in the development and pathogenesis of plant fungal pathogens.
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Affiliation(s)
- Ya Li
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiuxia Zheng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Minghui Zhu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Mengting Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shengnan Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Fangyuan He
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaomin Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jiarui Lv
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Mengtian Pei
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ye Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yunhui Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wenzong Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jing Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Mo Wang
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zonghua Wang
- Institute of Oceanography, Minjiang University, Fuzhou, China
| | - Guangpu Li
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Guodong Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
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Yamauchi N, Tanoue R. Deuterium incorporation experiments from (3R)- and (3S)-[3- 2H]leucine into characteristic isoprenoidal lipid-core of halophilic archaea suggests the involvement of isovaleryl-CoA dehydrogenase. Biosci Biotechnol Biochem 2017; 81:2062-2070. [PMID: 28942710 DOI: 10.1080/09168451.2017.1373588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The stereochemical reaction course for the two C-3 hydrogens of leucine to produce a characteristic isoprenoidal lipid in halophilic archaea was observed using incubation experiments with whole cell Halobacterium salinarum. Deuterium-labeled (3R)- and (3S)-[3-2H]leucine were freshly prepared as substrates from 2,3-epoxy-4-methyl-1-pentanol. Incorporation of deuterium from (3S)-[3-2H]leucine and loss of deuterium from (3R)-[3-2H]leucine in the lipid-core of H. salinarum was observed. Taken together with the results of our previous report, involving the incubation of chiral-labeled [5-2H]leucine, these results strongly suggested an involvement of isovaleryl-CoA dehydrogenase in leucine conversion to isoprenoid lipid in halophilic archaea. The stereochemical course of the reaction (anti-elimination) might have been the same as that previously reported for mammalian enzyme reactions. Thus, these results suggested that branched amino acids were metabolized to mevalonate in archaea in a manner similar to other organisms.
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Affiliation(s)
- Noriaki Yamauchi
- a Department of Earth and Planetary Sciences, Graduate School of Sciences , Kyushu University , Fukuoka , Japan
| | - Ryo Tanoue
- a Department of Earth and Planetary Sciences, Graduate School of Sciences , Kyushu University , Fukuoka , Japan
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3
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Galili G, Amir R, Fernie AR. The Regulation of Essential Amino Acid Synthesis and Accumulation in Plants. ANNUAL REVIEW OF PLANT BIOLOGY 2016; 67:153-78. [PMID: 26735064 DOI: 10.1146/annurev-arplant-043015-112213] [Citation(s) in RCA: 166] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Although amino acids are critical for all forms of life, only proteogenic amino acids that humans and animals cannot synthesize de novo and therefore must acquire in their diets are classified as essential. Nine amino acids-lysine, methionine, threonine, phenylalanine, tryptophan, valine, isoleucine, leucine, and histidine-fit this definition. Despite their nutritional importance, several of these amino acids are present in limiting quantities in many of the world's major crops. In recent years, a combination of reverse genetic and biochemical approaches has been used to define the genes encoding the enzymes responsible for synthesizing, degrading, and regulating these amino acids. In this review, we describe recent advances in our understanding of the metabolism of the essential amino acids, discuss approaches for enhancing their levels in plants, and appraise efforts toward their biofortification in crop plants.
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Affiliation(s)
- Gad Galili
- Department of Plant Science, Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Rachel Amir
- Laboratory of Plant Science, MIGAL-Galilee Research Institute, Kiryat Shmona 11016, Israel;
| | - Alisdair R Fernie
- Max Planck Institute for Molecular Plant Physiology, 14476 Potsdam-Golm, Germany;
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Transcriptome and Proteome Expression Analysis of the Metabolism of Amino Acids by the Fungus Aspergillus oryzae in Fermented Soy Sauce. BIOMED RESEARCH INTERNATIONAL 2015; 2015:456802. [PMID: 25945335 PMCID: PMC4405012 DOI: 10.1155/2015/456802] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/07/2015] [Accepted: 01/18/2015] [Indexed: 11/17/2022]
Abstract
Amino acids comprise the majority of the flavor compounds in soy sauce. A portion of these amino acids are formed from the biosynthesis and metabolism of the fungus Aspergillus oryzae; however, the metabolic pathways leading to the formation of these amino acids in A. oryzae remain largely unknown. We sequenced the transcriptomes of A. oryzae 100-8 and A. oryzae 3.042 under similar soy sauce fermentation conditions. 2D gel electrophoresis was also used to find some differences in protein expression. We found that many amino acid hydrolases (endopeptidases, aminopeptidases, and X-pro-dipeptidyl aminopeptidase) were expressed at much higher levels (mostly greater than double) in A. oryzae 100-8 than in A. oryzae 3.042. Our results indicated that glutamate dehydrogenase may activate the metabolism of amino acids. We also found that the expression levels of some genes changed simultaneously in the metabolic pathways of tyrosine and leucine and that these conserved genes may modulate the function of the metabolic pathway. Such variation in the metabolic pathways of amino acids is important as it can significantly alter the flavor of fermented soy sauce.
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Schertl P, Braun HP. Respiratory electron transfer pathways in plant mitochondria. FRONTIERS IN PLANT SCIENCE 2014; 5:163. [PMID: 24808901 PMCID: PMC4010797 DOI: 10.3389/fpls.2014.00163] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/07/2014] [Indexed: 05/18/2023]
Abstract
The respiratory electron transport chain (ETC) couples electron transfer from organic substrates onto molecular oxygen with proton translocation across the inner mitochondrial membrane. The resulting proton gradient is used by the ATP synthase complex for ATP formation. In plants, the ETC is especially intricate. Besides the "classical" oxidoreductase complexes (complex I-IV) and the mobile electron transporters cytochrome c and ubiquinone, it comprises numerous "alternative oxidoreductases." Furthermore, several dehydrogenases localized in the mitochondrial matrix and the mitochondrial intermembrane space directly or indirectly provide electrons for the ETC. Entry of electrons into the system occurs via numerous pathways which are dynamically regulated in response to the metabolic state of a plant cell as well as environmental factors. This mini review aims to summarize recent findings on respiratory electron transfer pathways in plants and on the involved components and supramolecular assemblies.
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Affiliation(s)
| | - Hans-Peter Braun
- Abteilung Pflanzenproteomik, Institut für Pflanzengenetik, Leibniz Universität HannoverHannover, Germany
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Binder S. Branched-Chain Amino Acid Metabolism in Arabidopsis thaliana. THE ARABIDOPSIS BOOK 2010; 8:e0137. [PMID: 22303262 PMCID: PMC3244963 DOI: 10.1199/tab.0137] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Valine, leucine and isoleucine form the small group of branched-chain amino acids (BCAAs) classified by their small branched hydrocarbon residues. Unlike animals, plants are able to de novo synthesize these amino acids from pyruvate, 2-oxobutanoate and acetyl-CoA. In plants, biosynthesis follows the typical reaction pathways established for the formation of these amino acids in microorganisms. Val and Ile are synthesized in two parallel pathways using a single set of enzymes. The pathway to Leu branches of from the final intermediate of Val biosynthesis. The formation of this amino acid requires a three-step pathway generating a 2-oxoacid elongated by a methylene group. In Arabidopsis thaliana and other Brassicaceae, a homologous three-step pathway is also involved in Met chain elongation required for the biosynthesis of aliphatic glucosinolates, an important class of specialized metabolites in Brassicaceae. This is a prime example for the evolutionary relationship of pathways from primary and specialized metabolism. Similar to animals, plants also have the ability to degrade BCAAs. The importance of BCAA turnover has long been unclear, but now it seems apparent that the breakdown process might by relevant under certain environmental conditions. In this review, I summarize the current knowledge about BCAA metabolism, its regulation and its particular features in Arabidopsis thaliana.
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Affiliation(s)
- Stefan Binder
- Institute Molecular Botany, Ulm University, Albert-Einstein-Allee 11, 89060 Ulm, Germany Address correspondence to
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Lopes MS, Araus JL. Comparative genomic and physiological analysis of nutrient response to NH4+, NH4+:NO3- and NO3- in barley seedlings. PHYSIOLOGIA PLANTARUM 2008; 134:134-50. [PMID: 18544123 DOI: 10.1111/j.1399-3054.2008.01114.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Long-term differences in photosynthesis, respiration and growth of plants receiving distinct nitrogen (N) sources imply that N metabolism generates signals that regulate metabolism and development. The molecular basis of these signals remains unclear. Here we studied the gene expression profiles of barley (Hordeum vulgare L. cv. Graphic) seedlings fertilized either with ammonium (NH4+), with ammonium and nitrate (NH4+:NO3-), or with nitrate (NO3-) only. Our transcriptome analysis after 48 h of growth in these N sources showed major changes in the expression of genes involved in N metabolism (nitrate reductase), signalling (protein kinases and protein phosphatases), photosynthesis (chlorophyll a/b-binding protein and a PsbQ domain), where increases in NO3- as compared with NH4+ were observed. Moreover, NH4+ assimilation induced genes participating in C and sugars metabolism (phosphoglycerate kinase, glucosyltranferase and galactokinase), respiration (cytochrome c oxidase), protein fate (heat shock proteins) and development (MTN3-like protein). These changes in gene expression could well explain the long-term growth depression observed in NH4+ plants. Even if a few genes participating in protein fate (proteases) and development (OsNAC5) were upregulated in NH4+ as compared with NH4+:NO3-, the general pattern of expression was quite similar between these two N sources. Taken together, these results indicated that other downstream mechanisms should be involved in the synergetic long-term response of NH4+:NO3-.
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Affiliation(s)
- Marta S Lopes
- Facultat de Biologia, Unitat de Fisiologia Vegetal, Universitat de Barcelona, Barcelona, Spain
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Lauer B, Ottleben I, Jacobsen HJ, Reinard T. Production of a single-chain variable fragment antibody against fumonisin B1. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:899-904. [PMID: 15712995 DOI: 10.1021/jf048651s] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The selection of synthetic antibody fragments from large phage libraries has become a common method for the generation of specific antibodies. The technique is particularly valuable when antibodies against small, non-immunogenic molecules (haptens) or highly toxic substances have to be produced. In addition, haptens are usually coupled to protein carriers, bearing the risk that the free hapten is not detectable. Here, a single variable chain antibody (scFv) against the highly toxic mycotoxin fumonisin B1 has been produced. The hapten was coupled via a linker to biotin. Using this conjugate and a naive scFv library, it was possible to circumvent both the necessity of immunization and the risk of a disguised hapten. The scFv obtained after three panning rounds was found to bind specifically to both free fumonisin B1 and fumonisin-biotin conjugate. Also fumonisin B2 was bound by the scFv. Modeling of both scFv and fumonisin B1 molecule revealed a good fitting of structures. The antibody obtained can potentially be used for developing a rapid and affordable immunoassay for detection of food contamination and can be applied in immunoaffinity chromatography, usually carried out prior to HPLC analysis of mycotoxin-contaminated food and feed.
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Affiliation(s)
- Björn Lauer
- LG Molekulargenetik, University of Hannover, Herrenhäuser Strasse 2, D-30419 Hannover, Germany
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9
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Schuster J, Binder S. The mitochondrial branched-chain aminotransferase (AtBCAT-1) is capable to initiate degradation of leucine, isoleucine and valine in almost all tissues in Arabidopsis thaliana. PLANT MOLECULAR BIOLOGY 2005; 57:241-54. [PMID: 15821880 DOI: 10.1007/s11103-004-7533-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Accepted: 12/12/2004] [Indexed: 05/02/2023]
Abstract
Plants are capable to de novo synthesize the essential amino acids leucine, isoleucine and valine. Studies in recent years, however, also revealed that plants have the potential to degrade leucine or may be all of the branched-chain amino acids. One of the enzymes participating in both biosynthesis and degradation is the branched-chain aminotransferase, which is in Arabidopsis thaliana encoded by a small gene family with six transcribed members. We have now studied the steady state mRNA levels by quantitative RT-PCR and promoter activities of these genes with promoter::glucuronidase reporter gene constructs in transgenic plants. The gene encoding the mitochondrial isoenzyme (Atbcat-1) is expressed in all tissues with predominant transcription in seedlings and leaves. Surprisingly the plastid located proteins (AtBCAT-2, -3 and -5) are expressed at rather low levels with only Atbcat-3 transcribed in all tissues. The most likely cytoplasmic-located AtBCAT-4 and AtBCAT-6 are mainly expressed in tissues associated with transport function and in meristematic tissues, respectively. A detailed characterization of the enzyme activity and substrate specificity of the mitochondrial AtBCAT-1 enzyme revealed the potential of this enzyme to initiate degradation of all branched-chain amino acids. In addition alpha-aminobutyrate and alpha-ketobutyrate as well as methionine and alpha-ketomethylthiobutyrate are identified as substrates. This suggests that AtBCAT-1 and potentially other members of this protein family may influence methionine levels and may play an important role in the metabolism of the nonprotein amino acid alpha-aminobutyrate. The consequences of these substrate specificities for bioplastic production and methionine homeostasis are discussed.
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Affiliation(s)
- Joachim Schuster
- Molekulare Botanik, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
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Goetzman ES, Mohsen AWA, Prasad K, Vockley J. Convergent evolution of a 2-methylbutyryl-CoA dehydrogenase from isovaleryl-CoA dehydrogenase in Solanum tuberosum. J Biol Chem 2004; 280:4873-9. [PMID: 15574432 DOI: 10.1074/jbc.m412640200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The potato cDNAs Solanum tuberosum isovaleryl-CoA dehydrogenases 1 and 2 (St-IVD1 and St-IVD2) encode proteins that are 84% identical to each other and 65 and 64% identical to human IVD, respectively. St-IVD2 protein was previously partially purified from potato tubers and confirmed to be an IVD. The function of St-IVD1 is unknown. In these experiments, both proteins were expressed in Escherichia coli and purified as intact homotetramers. The substrate preference profile of the St-IVD2 protein was similar to that of human IVD. However, recombinant St-IVD1 had maximal activity with 2-methylbutyryl-CoA, which in humans is dehydrogenated by short/branched-chain acyl-CoA dehydrogenase (SBCAD). Whereas molecular modeling predicts that the 2-methylbutyryl-CoA dehydrogenase (2MBCD) and IVD substrate binding pockets are nearly identical, 2MBCD has amino acid substitutions at five residues that are invariant among all of the known and putative IVDs. Site-directed mutagenesis was used to match the human IVD active site with that of potato 2MBCD. The resulting mutant IVD had detectable activity with 2-methylbutyryl-CoA and no activity with isovaleryl-CoA. The 2MBCD active site was compared with that of human SBCAD using molecular modeling. Residues Met-361 and Ala-365 of 2MBCD appear to partially substitute for the function of Tyr-380 in human SBCAD, binding the methyl branch linked to C2 of 2-methylbutyryl-CoA, whereas residues Val-88, Val-92, and Val-96 appear to bind the distal C4 methyl group. The presence of a 2MBCD in potato that is highly homologous to IVD is an example of convergent evolution within the acyl-CoA dehydrogenase family, leading to the independent occurrence of two enzymes (SBCAD and 2MBCD) specific for 2-methylbutyryl-CoA.
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Affiliation(s)
- Eric S Goetzman
- Department of Pediatrics, School of Medicine and Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
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Angeles Castillejo M, Amiour N, Dumas-Gaudot E, Rubiales D, Jorrín JV. A proteomic approach to studying plant response to crenate broomrape (Orobanche crenata) in pea (Pisum sativum). PHYTOCHEMISTRY 2004; 65:1817-28. [PMID: 15276440 DOI: 10.1016/j.phytochem.2004.03.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 03/15/2004] [Indexed: 05/22/2023]
Abstract
Crenate broomrape (Orobanche crenata) is a parasitic plant that threatens legume production in Mediterranean areas. Pea (Pisum sativum) is severely affected, and only moderate levels of genetic resistance have so far been identified. In the present work we selected the most resistant accession available (Ps 624) and compared it with a susceptible (Messire) cultivar. Experiments were performed by using pot and Petri dish bioassays, showing little differences in the percentage of broomrape seed germination induced by both genotypes, but a significant hamper in the number of successfully installed tubercles and their developmental stage in the Ps 624 compared to Messire. The protein profile of healthy and infected P. sativum root tissue were analysed by two-dimensional electrophoresis. Approximately 500 individual protein spots could be detected on silver stained gels. At least 22 different protein spots differentiated control, non-infected, Messire and Ps 624 accessions. Some of them were identified by MALDI-TOF mass spectrometry and database searching as cysteine proteinase, beta-1,3-glucanase, endochitinase, profucosidase, and ABA-responsive protein. Both qualitative and quantitative differences have been found among infected and non-infected root extracts. Thus, in the infected susceptible Messire genotype 34 spots were decreased, one increased and three newly detected, while in Ps 624, 15 spots were increased, three decreased and one newly detected. In response to the inoculation, proteins that correspond to enzymes of the carbohydrate metabolism (fructokinase, fructose-bisphosphate aldolase), nitrogen metabolism (ferredoxin-NADP reductase) and mitochondrial electronic chain transport (alternative oxidase 2) decreased in the susceptible check, while proteins that correspond to enzymes of the nitrogen assimilation pathway (glutamine synthetase) or typical pathogen defence, PR proteins, including beta-1,3-glucanase and peroxidases, increased in Ps 624. Results are discussed in terms of changes in the carbohydrate and nitrogen metabolism an induction of defence proteins in response to broomrape parasitism.
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Affiliation(s)
- M Angeles Castillejo
- Agricultural and Plant Biochemistry Research Group, Department of Biochemistry and Molecular Biology, University of Córdoba, Campus de Rabanales, Edificio Severo Ochoa (C6), 14071 Córdoba, Spain
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12
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Frenzel A, Bergemann C, Köhl G, Reinard T. Novel purification system for 6xHis-tagged proteins by magnetic affinity separation. J Chromatogr B Analyt Technol Biomed Life Sci 2003; 793:325-9. [PMID: 12906907 DOI: 10.1016/s1570-0232(03)00332-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have developed a novel nickel-silica matrix for the generation of magnetic beads for metal-ion affinity chromatography. In contrast to magnetic Ni-NTA agarose beads, the novel particle type (SiMAC) consists of a magnetic core and a nickel-silica composite matrix with the nickel ions tightly integrated in the silica. This results in a much higher number of chelating groups compared with Ni-NTA agarose beads. With the SiMAC beads, greatly improved purification of histidine-tagged proteins from crude bacterial extracts was achieved. The yield was at least twice as high as with conventional materials, the method is faster, since the coupling step is omitted and there is no need for handling toxic Ni(2+) salts.
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Affiliation(s)
- André Frenzel
- Lehrgebiet Molekulargenetik, Universität Hannover, Herrenhäuser Strasse 2, D-30419 Hannover, Germany
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Hust M, Maiss E, Jacobsen HJ, Reinard T. The production of a genus-specific recombinant antibody (scFv) using a recombinant potyvirus protease. J Virol Methods 2002; 106:225-33. [PMID: 12393153 DOI: 10.1016/s0166-0934(02)00166-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A single chain variable fragment antibody (scFv; anti-NIa scFv102) was selected from a synthetic human antibody library by using a NIa protease of Plum pox virus (PPV) as an antigen, which was expressed in bacteria. The NIa protease forms the nuclear inclusion body A and acts as the major protease in the cleavage of the viral polyprotein into functional proteins. The NIa protein was detected with anti-NIa scFv102 after expression in Escherichia coli cells as well as from PPV-infected Nicotiana benthamiana plants. Furthermore, the scFv102 has the ability to identify not only PPV from infected plants but also can detect other infections with members of the potyviruses. Nineteen different potyviruses were recognized by the scFv102 in various infected plants tested through dot blot assays. Therefore, the antibody scFv102 has the potential of becoming a general tool to detect potyvirus infections in different plant species.
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Affiliation(s)
- Michael Hust
- Lehrgebiet Molekulargenetik, Universität Hannover, Herrenhäuser Strasse 2, D-30419 Hannover, Germany
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14
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Diebold R, Schuster J, Däschner K, Binder S. The branched-chain amino acid transaminase gene family in Arabidopsis encodes plastid and mitochondrial proteins. PLANT PHYSIOLOGY 2002; 129:540-50. [PMID: 12068099 PMCID: PMC161671 DOI: 10.1104/pp.001602] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2001] [Revised: 01/29/2002] [Accepted: 02/12/2002] [Indexed: 05/17/2023]
Abstract
Branched-chain amino acid transaminases (BCATs) play a crucial role in the metabolism of leucine, isoleucine, and valine. They catalyze the last step of the synthesis and/or the initial step of the degradation of this class of amino acids. In Arabidopsis, seven putative BCAT genes are identified by their similarity to their counterparts from other organisms. We have now cloned the respective cDNA sequences of six of these genes. The deduced amino acid sequences show between 47.5% and 84.1% identity to each other and about 30% to the homologous enzymes from yeast (Saccharomyces cerevisiae) and mammals. In addition, many amino acids in crucial positions as determined by crystallographic analyses of BCATs from Escherichia coli and human (Homo sapiens) are conserved in the AtBCATs. Complementation of a yeast Deltabat1/Deltabat2 double knockout strain revealed that five AtBCATs can function as BCATs in vivo. Transient expression of BCAT:green fluorescent protein fusion proteins in tobacco (Nicotiana tabacum) protoplasts shows that three isoenzymes are imported into chloroplasts (AtBCAT-2, -3, and -5), whereas a single enzyme is directed into mitochondria (AtBCAT-1).
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Affiliation(s)
- Ruth Diebold
- Molekulare Botanik, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
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Shimoda K, Izumi S, Hirata T. A Novel Reductase Participating in the Hydrogenation of an Exocyclic C–C Double Bond of Enones fromNicotiana tabacum. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2002. [DOI: 10.1246/bcsj.75.813] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Zolman BK, Monroe-Augustus M, Thompson B, Hawes JW, Krukenberg KA, Matsuda SP, Bartel B. chy1, an Arabidopsis mutant with impaired beta-oxidation, is defective in a peroxisomal beta-hydroxyisobutyryl-CoA hydrolase. J Biol Chem 2001; 276:31037-46. [PMID: 11404361 DOI: 10.1074/jbc.m104679200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The Arabidopsis chy1 mutant is resistant to indole-3-butyric acid, a naturally occurring form of the plant hormone auxin. Because the mutant also has defects in peroxisomal beta-oxidation, this resistance presumably results from a reduced conversion of indole-3-butyric acid to indole-3-acetic acid. We have cloned CHY1, which appears to encode a peroxisomal protein 43% identical to a mammalian valine catabolic enzyme that hydrolyzes beta-hydroxyisobutyryl-CoA. We demonstrated that a human beta-hydroxyisobutyryl-CoA hydrolase functionally complements chy1 when redirected from the mitochondria to the peroxisomes. We expressed CHY1 as a glutathione S-transferase (GST) fusion protein and demonstrated that purified GST-CHY1 hydrolyzes beta-hydroxyisobutyryl-CoA. Mutagenesis studies showed that a glutamate that is catalytically essential in homologous enoyl-CoA hydratases was also essential in CHY1. Mutating a residue that is differentially conserved between hydrolases and hydratases established that this position is relevant to the catalytic distinction between the enzyme classes. It is likely that CHY1 acts in peroxisomal valine catabolism and that accumulation of a toxic intermediate, methacrylyl-CoA, causes the altered beta-oxidation phenotypes of the chy1 mutant. Our results support the hypothesis that the energy-intensive sequence unique to valine catabolism, where an intermediate CoA ester is hydrolyzed and a new CoA ester is formed two steps later, avoids methacrylyl-CoA accumulation.
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Affiliation(s)
- B K Zolman
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005, USA
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Mohsen AW, Navarette B, Vockley J. Identification of Caenorhabditis elegans isovaleryl-CoA dehydrogenase and structural comparison with other acyl-CoA dehydrogenases. Mol Genet Metab 2001; 73:126-37. [PMID: 11386848 DOI: 10.1006/mgme.2001.3183] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isovaleryl-CoA dehydrogenase (IVD) is a flavoenzyme, which catalyzes the conversion of isovaleryl-CoA to 3-methylcrotonyl-CoA in the leucine catabolism pathway and transfers electrons to the electron-transferring flavoprotein (ETF). IVDs from human and rat have been identified and characterized previously. In this study, the gene coding for Caenorhabditis elegans IVD has been identified from a published cDNA sequence and molecular modeling has been performed using the human IVD atomic coordinates. The coding sequence for the mature form of the enzyme was expressed in Escherichia coli, and the recombinant nematode IVD enzyme was purified to essential homogeneity. Its spectrum is typical of recombinant FAD-containing acyl-CoA dehydrogenases and shows a minor broad absorption band at 650-700 nm characteristic of an IVD:CoA persulfide charge-transfer complex. Following treatment of the enzyme with sodium dithionite to remove the bound CoA persulfide, the K(m) values for isovaleryl-, butyryl-, valeryl-, and hexanoyl-CoA were estimated to be 2.5, 36.2, 10.5, and 33.8 microM, respectively, using the ETF fluorescence reduction assay. The catalytic efficiency (k(cat)/K(m)) for these substrates was 56.9, 1.3, 13.7, and 3.2 microM(-1). min(-1) per mole of FAD, respectively. The apparent binding constant (K(D app)) of the recombinant IVD determined spectrally for isovaleryl-CoA was 0.34 microM. These kinetic parameters confirm that isovaleryl-CoA is the preferred substrate for the purified enzyme. The variability in the protein structure among known and putative IVDs from various species is discussed in the context of possible mechanisms for modulating enzyme activity.
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Affiliation(s)
- A W Mohsen
- Department of Medical Genetics, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA
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Willard JM, Reinard T, Mohsen A, Vockley J. Cloning of genomic and cDNA for mouse isovaleryl-CoA dehydrogenase (IVD) and evolutionary comparison to other known IVDs. Gene 2001; 270:253-7. [PMID: 11404023 DOI: 10.1016/s0378-1119(01)00466-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Isovaleryl-CoA dehydrogenase (IVD) is an intramitochondrial homotetrameric flavoenzyme that catalyzes the conversion of isovaleryl-CoA to 3-methylcrotonyl-CoA in the leucine catabolism pathway. Deficiency of IVD in humans causes isovaleric acidemia, which shows tremendous clinical variability for reasons that are unknown. To help better understand this disorder, we have cloned and sequenced the mouse IVD genomic and cDNAs. The mouse IVD gene spans approximately 17 kb and contains 12 coding exons organized identically to the human gene. It maps to mouse chromosome 2 in the area of band 2E4-E5, corresponding to the syntenic region of human chromosome 15. Mouse IVD predicted amino acid sequences are 95.8 and 89.6% identical to that of the rat and human sequences, respectively, with conservation of key functional residues. We have now identified IVD sequences from seven species. Comparison of these sequences shows that the rat and mouse proteins are the most closely related, both of which, in turn, share highest homology to human. All of the mammalian enzymes appear to be more closely related than any of the IVDs on other branches of the phylogram, while the fly and worm IVDs are the most divergent. The invertebrate IVDs are more closely related to the mammalian enzymes than to those from two plant species.
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Affiliation(s)
- J M Willard
- Department of Medical Genetics, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA
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