1
|
Heimhalt M, Mukherjee P, Grainger RA, Szabla R, Brown C, Turner R, Junop MS, Berti PJ. An Inhibitor-in-Pieces Approach to DAHP Synthase Inhibition: Potent Enzyme and Bacterial Growth Inhibition. ACS Infect Dis 2021; 7:3292-3302. [PMID: 34761906 DOI: 10.1021/acsinfecdis.1c00462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
3-Deoxy-d-arabinoheptulosonate-7-phosphate (DAHP) synthase catalyzes the first step in the shikimate biosynthetic pathway and is an antimicrobial target. We used an inhibitor-in-pieces approach, based on the previously reported inhibitor DAHP oxime, to screen inhibitor fragments in the presence and absence of glycerol 3-phosphate to occupy the distal end of the active site. This led to DAHP hydrazone, the most potent inhibitor to date, Ki = 10 ± 1 nM. Three trifluoropyruvate (TFP)-based inhibitor fragments were efficient inhibitors with ligand efficiencies of up to 0.7 kcal mol-1/atom compared with 0.2 kcal mol-1/atom for a typical good inhibitor. The crystal structures showed the TFP-based inhibitors binding upside down in the active site relative to DAHP oxime, providing new avenues for inhibitor development. The ethyl esters of TFP oxime and TFP semicarbazone prevented E. coli growth in culture with IC50 = 0.21 ± 0.01 and 0.77 ± 0.08 mg mL-1, respectively. Overexpressing DAHP synthase relieved growth inhibition, demonstrating that DAHP synthase was the target. Growth inhibition occurred in media containing aromatic amino acids, suggesting that growth inhibition was due to depletion of some other product(s) of the shikimate pathway, possibly folate.
Collapse
Affiliation(s)
| | | | - Ryan A. Grainger
- Department of Biochemistry, Molecular Biology Lab, Western University, London, Ontario N6A 5C1, Canada
| | - Robert Szabla
- Department of Biochemistry, Molecular Biology Lab, Western University, London, Ontario N6A 5C1, Canada
| | - Christopher Brown
- Department of Biochemistry, Molecular Biology Lab, Western University, London, Ontario N6A 5C1, Canada
| | | | - Murray S. Junop
- Department of Biochemistry, Molecular Biology Lab, Western University, London, Ontario N6A 5C1, Canada
| | | |
Collapse
|
2
|
Benevenuto RF, Zanatta CB, Guerra MP, Nodari RO, Agapito-Tenfen SZ. Proteomic Profile of Glyphosate-Resistant Soybean under Combined Herbicide and Drought Stress Conditions. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112381. [PMID: 34834744 PMCID: PMC8622064 DOI: 10.3390/plants10112381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 05/14/2023]
Abstract
While some genetically modified (GM) plants have been targeted to confer tolerance to abiotic stressors, transgenes are impacted by abiotic stressors, causing adverse effects on plant physiology and yield. However, routine safety analyses do not assess the response of GM plants under different environmental stress conditions. In the context of climate change, the combination of abiotic stressors is a reality in agroecosystems. Therefore, the aim of this study was to analyze the metabolic cost by assessing the proteomic profiles of GM soybean varieties under glyphosate spraying and water deficit conditions compared to their non-transgenic conventional counterparts. We found evidence of cumulative adverse effects that resulted in the reduction of enzymes involved in carbohydrate metabolism, along with the expression of amino acids and nitrogen metabolic enzymes. Ribosomal metabolism was significantly enriched, particularly the protein families associated with ribosomal complexes L5 and L18. The interaction network map showed that the affected module representing the ribosome pathway interacts strongly with other important proteins, such as the chloro-plastic gamma ATP synthase subunit. Combined, these findings provide clear evidence for increasing the metabolic costs of GM soybean plants in response to the accumulation of stress factors. First, alterations in the ribosome pathway indicate that the GM plant itself carries a metabolic burden associated with the biosynthesis of proteins as effects of genetic transformation. GM plants also showed an imbalance in energy demand and production under controlled conditions, which was increased under drought conditions. Identifying the consequences of altered metabolism related to the interaction between plant transgene stress responses allows us to understand the possible effects on the ecology and evolution of plants in the medium and long term and the potential interactions with other organisms when these organisms are released in the environment.
Collapse
Affiliation(s)
- Rafael Fonseca Benevenuto
- Crop Science Department, Federal University of Santa Catarina, Florianopolis 88034000, Brazil; (R.F.B.); (C.B.Z.); (M.P.G.); (R.O.N.)
| | - Caroline Bedin Zanatta
- Crop Science Department, Federal University of Santa Catarina, Florianopolis 88034000, Brazil; (R.F.B.); (C.B.Z.); (M.P.G.); (R.O.N.)
| | - Miguel Pedro Guerra
- Crop Science Department, Federal University of Santa Catarina, Florianopolis 88034000, Brazil; (R.F.B.); (C.B.Z.); (M.P.G.); (R.O.N.)
| | - Rubens Onofre Nodari
- Crop Science Department, Federal University of Santa Catarina, Florianopolis 88034000, Brazil; (R.F.B.); (C.B.Z.); (M.P.G.); (R.O.N.)
| | - Sarah Z. Agapito-Tenfen
- GenØk Centre for Biosafety, Siva Innovasjonssenter Postboks 6418, 9294 Tromsø, Norway
- Correspondence:
| |
Collapse
|
3
|
Hertel R, Gibhardt J, Martienssen M, Kuhn R, Commichau FM. Molecular mechanisms underlying glyphosate resistance in bacteria. Environ Microbiol 2021; 23:2891-2905. [PMID: 33876549 DOI: 10.1111/1462-2920.15534] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/10/2021] [Accepted: 04/14/2021] [Indexed: 11/29/2022]
Abstract
Glyphosate is a nonselective herbicide that kills weeds and other plants competing with crops. Glyphosate specifically inhibits the 5-enolpyruvyl-shikimate-3-phosphate (EPSP) synthase, thereby depleting the cell of EPSP serving as a precursor for biosynthesis of aromatic amino acids. Glyphosate is considered to be toxicologically safe for animals and humans. Therefore, it became the most-important herbicide in agriculture. However, its intensive application in agriculture is a serious environmental issue because it may negatively affect the biodiversity. A few years after the discovery of the mode of action of glyphosate, it has been observed that bacteria evolve glyphosate resistance by acquiring mutations in the EPSP synthase gene, rendering the encoded enzyme less sensitive to the herbicide. The identification of glyphosate-resistant EPSP synthase variants paved the way for engineering crops tolerating increased amounts of the herbicide. This review intends to summarize the molecular mechanisms underlying glyphosate resistance in bacteria. Bacteria can evolve glyphosate resistance by (i) reducing glyphosate sensitivity or elevating production of the EPSP synthase, by (ii) degrading or (iii) detoxifying glyphosate and by (iv) decreasing the uptake or increasing the export of the herbicide. The variety of glyphosate resistance mechanisms illustrates the adaptability of bacteria to anthropogenic substances due to genomic alterations.
Collapse
Affiliation(s)
- Robert Hertel
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, 01968, Germany
| | - Johannes Gibhardt
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, 01968, Germany
| | - Marion Martienssen
- Institute of Environmental Technology, Chair of Biotechnology of Water Treatment, BTU Cottbus-Senftenberg, Cottbus, 03046, Germany
| | - Ramona Kuhn
- Institute of Environmental Technology, Chair of Biotechnology of Water Treatment, BTU Cottbus-Senftenberg, Cottbus, 03046, Germany
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, 01968, Germany
| |
Collapse
|
4
|
The Yeast Atlas of Appalachia: Species and Phenotypic Diversity of Herbicide Resistance in Wild Yeast. DIVERSITY 2020. [DOI: 10.3390/d12040139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Glyphosate and copper-based herbicides/fungicides affect non-target organisms, and these incidental exposures can impact microbial populations. In this study, glyphosate resistance was found in the historical collection of S. cerevisiae, which was collected over the last century, but only in yeast isolated after the introduction of glyphosate. Although herbicide application was not recorded, the highest glyphosate-resistant S. cerevisiae were isolated from agricultural sites. In an effort to assess glyphosate resistance and impact on non-target microorganisms, different yeast species were harvested from 15 areas with known herbicidal histories, including an organic farm, conventional farm, remediated coal mine, suburban locations, state park, and a national forest. Yeast representing 23 genera were isolated from 237 samples of plant, soil, spontaneous fermentation, nut, flower, fruit, feces, and tree material samples. Saccharomyces, Candida, Metschnikowia, Kluyveromyces, Hanseniaspora, and Pichia were other genera commonly found across our sampled environments. Managed areas had less species diversity, and at the brewery only Saccharomyces and Pichia were isolated. A conventional farm growing RoundUp Ready™ corn had the lowest phylogenetic diversity and the highest glyphosate resistance. The mine was sprayed with multiple herbicides including a commercial formulation of glyphosate; however, the S. cerevisiae did not have elevated glyphosate resistance. In contrast to the conventional farm, the mine was exposed to glyphosate only one year prior to sample isolation. Glyphosate resistance is an example of the anthropogenic selection of nontarget organisms.
Collapse
|
5
|
Döring J, Rettke D, Rödel G, Pompe T, Ostermann K. Surface Functionalization by Hydrophobin-EPSPS Fusion Protein Allows for the Fast and Simple Detection of Glyphosate. BIOSENSORS 2019; 9:E104. [PMID: 31470576 PMCID: PMC6784374 DOI: 10.3390/bios9030104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/15/2019] [Accepted: 08/26/2019] [Indexed: 02/04/2023]
Abstract
Glyphosate, the most widely used pesticide worldwide, is under debate due to its potentially cancerogenic effects and harmful influence on biodiversity and environment. Therefore, the detection of glyphosate in water, food or environmental probes is of high interest. Currently detection of glyphosate usually requires specialized, costly instruments, is labor intensive and time consuming. Here we present a fast and simple method to detect glyphosate in the nanomolar range based on the surface immobilization of glyphosate's target enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) via fusion to the hydrophobin Ccg2 and determination of enzyme activity with a malachite green assay, which is a common photometric technique to measure inorganic phosphate (Pi). The assay demonstrates a new approach for a fast and simple detection of pesticides.
Collapse
Affiliation(s)
- Julia Döring
- Institute of Genetics, Technische Universität Dresden, Zellescher Weg 20b, 01217 Dresden, Germany.
| | - David Rettke
- Institute of Biochemistry, Leipzig University, Johannisallee 21-23, 04103 Leipzig, Germany
| | - Gerhard Rödel
- Institute of Genetics, Technische Universität Dresden, Zellescher Weg 20b, 01217 Dresden, Germany
| | - Tilo Pompe
- Institute of Biochemistry, Leipzig University, Johannisallee 21-23, 04103 Leipzig, Germany
| | - Kai Ostermann
- Institute of Genetics, Technische Universität Dresden, Zellescher Weg 20b, 01217 Dresden, Germany
| |
Collapse
|
6
|
Silver RJ, Paczosa MK, McCabe AL, Balada-Llasat JM, Baleja JD, Mecsas J. Amino Acid Biosynthetic Pathways Are Required for Klebsiella pneumoniae Growth in Immunocompromised Lungs and Are Druggable Targets during Infection. Antimicrob Agents Chemother 2019; 63:e02674-18. [PMID: 31109974 PMCID: PMC6658747 DOI: 10.1128/aac.02674-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 05/11/2019] [Indexed: 12/16/2022] Open
Abstract
The emergence of multidrug-resistant Klebsiella pneumoniae has rendered a large array of infections difficult to treat. In a high-throughput genetic screen of factors required for K. pneumoniae survival in the lung, amino acid biosynthesis genes were critical for infection in both immunosuppressed and wild-type (WT) mice. The limited pool of amino acids in the lung did not change during infection and was insufficient for K. pneumoniae to overcome attenuating mutations in aroA, hisA, leuA, leuB, serA, serB, trpE, and tyrA in WT and immunosuppressed mice. Deletion of aroA, which encodes 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase class I, resulted in the most severe attenuation. Treatment with the EPSP synthase-specific competitive inhibitor glyphosate decreased K. pneumoniae growth in the lungs. K. pneumoniae expressing two previously identified glyphosate-resistant mutations in EPSP synthase had significant colonization defects in lung infection. Selection and characterization of six spontaneously glyphosate-resistant mutants in K. pneumoniae yielded no mutations in aroA Strikingly, glyphosate treatment of mice lowered the bacterial burden of two of three spontaneous glyphosate-resistant mutants and further lowered the burden of the less-attenuated EPSP synthase catalytic mutant. Of 39 clinical isolate strains, 9 were resistant to glyphosate at levels comparable to those of selected resistant strains, and none appeared to be more highly resistant. These findings demonstrate amino acid biosynthetic pathways essential for K. pneumoniae infection are promising novel therapeutic targets.
Collapse
Affiliation(s)
- Rebecca J Silver
- Graduate Program in Immunology, MERGE-ID Track, Sackler School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Michelle K Paczosa
- Graduate Program in Immunology, MERGE-ID Track, Sackler School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Anne L McCabe
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | | | - James D Baleja
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Joan Mecsas
- Graduate Program in Immunology, MERGE-ID Track, Sackler School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| |
Collapse
|
7
|
Wicke D, Schulz LM, Lentes S, Scholz P, Poehlein A, Gibhardt J, Daniel R, Ischebeck T, Commichau FM. Identification of the first glyphosate transporter by genomic adaptation. Environ Microbiol 2019; 21:1287-1305. [PMID: 30666812 DOI: 10.1111/1462-2920.14534] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/12/2023]
Abstract
The soil bacterium Bacillus subtilis can get into contact with growth-inhibiting substances, which may be of anthropogenic origin. Glyphosate is such a substance serving as a nonselective herbicide. Glyphosate specifically inhibits the 5-enolpyruvyl-shikimate-3-phosphate (EPSP) synthase, which generates an essential precursor for de novo synthesis of aromatic amino acids in plants, fungi, bacteria and archaea. Inhibition of the EPSP synthase by glyphosate results in depletion of the cellular levels of aromatic amino acids unless the environment provides them. Here, we have assessed the potential of B. subtilis to adapt to glyphosate at the genome level. In contrast to Escherichia coli, which evolves glyphosate resistance by elevating the production and decreasing the glyphosate sensitivity of the EPSP synthase, B. subtilis primarily inactivates the gltT gene encoding the high-affinity glutamate/aspartate symporter GltT. Further adaptation of the gltT mutants to glyphosate led to the inactivation of the gltP gene encoding the glutamate transporter GltP. Metabolome analyses confirmed that GltT is the major entryway of glyphosate into B. subtilis. GltP, the GltT homologue of E. coli also transports glyphosate into B. subtilis. Finally, we found that GltT is involved in uptake of the herbicide glufosinate, which inhibits the glutamine synthetase.
Collapse
Affiliation(s)
- Dennis Wicke
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Lisa M Schulz
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Sabine Lentes
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Patricia Scholz
- Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center of Molecular Biosciences (GZMB), University of Goettingen, 37077, Göttingen, Germany
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Johannes Gibhardt
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Till Ischebeck
- Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center of Molecular Biosciences (GZMB), University of Goettingen, 37077, Göttingen, Germany
| | - Fabian M Commichau
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| |
Collapse
|
8
|
Liu F, Cao Y. Expression of a bacterial aroA gene confers tolerance to glyphosate in tobacco plants. Turk J Biol 2019; 42:187-194. [PMID: 30814880 DOI: 10.3906/biy-1712-56] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Glyphosate is a widely used herbicide that inhibits the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS)-encoding aroA gene in the shikimate pathway. The discovery and cloning of the aroA gene with high resistance is central to breeding a transgenic glyphosate-resistant plant. A novel aroAPantoea gene from Pantoea G-1 was previously isolated and cloned. The aroA Pantoea enzyme was defined as a new class I EPSPS with glyphosate resistance. The aroA Pantoea gene was introduced into tobacco through Agrobacteriummediated transformation. The transgenic tobacco plants were confirmed by PCR, RT-PCR, and Southern blot. The analysis of glyphosate resistance also showed that the transgenic tobacco plants could survive at 15 mM glyphosate; the glyphosate resistance level of the transgenic plants is higher than the agricultural application level recommended by most manufacturers. Overall, this study shows that aroAPantoea can be used as a candidate gene for the development of genetically modified crops.
Collapse
Affiliation(s)
- Feng Liu
- Department of Plant Science, School of Agriculture and Biology, Shanghai Jiao Tong University , Shanghai , P. R. China
| | - Yueping Cao
- Department of Plant Science, School of Agriculture and Biology, Shanghai Jiao Tong University , Shanghai , P. R. China
| |
Collapse
|
9
|
Fang J, Nan P, Gu Z, Ge X, Feng YQ, Lu BR. Overexpressing Exogenous 5-Enolpyruvylshikimate-3-Phosphate Synthase (EPSPS) Genes Increases Fecundity and Auxin Content of Transgenic Arabidopsis Plants. FRONTIERS IN PLANT SCIENCE 2018; 9:233. [PMID: 29535747 PMCID: PMC5835131 DOI: 10.3389/fpls.2018.00233] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 02/09/2018] [Indexed: 05/24/2023]
Abstract
Transgenic glyphosate-tolerant plants overproducing EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) may exhibit enhanced fitness in glyphosate-free environments. If so, introgression of transgenes overexpressing EPSPS into wild relative species may lead to increased competitiveness of crop-wild hybrids, resulting in unpredicted environmental impact. Assessing fitness effects of transgenes overexpressing EPSPS in a model plant species can help address this question, while elucidating how overproducing EPSPS affects the fitness-related traits of plants. We produced segregating T2 and T3Arabidopsis thaliana lineages with or without a transgene overexpressing EPSPS isolated from rice or Agrobacterium (CP4). For each of the three transgenes, we compared glyphosate tolerance, some fitness-related traits, and auxin (indole-3-acetic acid) content in transgene-present, transgene-absent, empty vector (EV), and parental lineages in a common-garden experiment. We detected substantially increased glyphosate tolerance in T2 plants of transgene-present lineages that overproduced EPSPS. We also documented significant increases in fecundity, which was associated with increased auxin content in T3 transgene-present lineages containing rice EPSPS genes, compared with their segregating transgene-absent lineages, EV, and parental controls. Our results from Arabidopsis with nine transgenic events provide a strong support to the hypothesis that transgenic plants overproducing EPSPS can benefit from a fecundity advantage in glyphosate-free environments. Stimulated biosynthesis of auxin, an important plant growth hormone, by overproducing EPSPS may play a role in enhanced fecundity of the transgenic Arabidopsis plants. The obtained knowledge is useful for assessing environmental impact caused by introgression of transgenes overproducing EPSPS from any GE crop into populations of its wild relatives.
Collapse
Affiliation(s)
- Jia Fang
- Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering, Department of Ecology and Evolutionary Biology, Fudan University, Shanghai, China
| | - Peng Nan
- Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering, Department of Ecology and Evolutionary Biology, Fudan University, Shanghai, China
| | - Zongying Gu
- State Key Laboratory of Genetic Engineering, Department of Biochemistry and Molecular Biology, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, China
| | - Xiaochun Ge
- State Key Laboratory of Genetic Engineering, Department of Biochemistry and Molecular Biology, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, China
| | - Yu-Qi Feng
- Key Laboratory of Analytical Chemistry for Biology and Medicine, Ministry of Education, Department of Chemistry, Wuhan University, Wuhan, China
| | - Bao-Rong Lu
- Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering, Department of Ecology and Evolutionary Biology, Fudan University, Shanghai, China
| |
Collapse
|
10
|
Comparative genome analysis of the vineyard weed endophyte Pseudomonas viridiflava CDRTc14 showing selective herbicidal activity. Sci Rep 2017; 7:17336. [PMID: 29229911 PMCID: PMC5725424 DOI: 10.1038/s41598-017-16495-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 11/13/2017] [Indexed: 12/17/2022] Open
Abstract
Microbes produce a variety of secondary metabolites to be explored for herbicidal activities. We investigated an endophyte Pseudomonas viridiflava CDRTc14, which impacted growth of its host Lepidium draba L., to better understand the possible genetic determinants for herbicidal and host-interaction traits. Inoculation tests with a variety of target plants revealed that CDRTc14 shows plant-specific effects ranging from beneficial to negative. Its herbicidal effect appeared to be dose-dependent and resembled phenotypically the germination arrest factor of Pseudomonas fluorescens WH6. CDRTc14 shares 183 genes with the herbicidal strain WH6 but the formylaminooxyvinylglycine (FVG) biosynthetic genes responsible for germination arrest of WH6 was not detected. CDRTc14 showed phosphate solubilizing ability, indole acetic acid and siderophores production in vitro and harbors genes for these functions. Moreover, genes for quorum sensing, hydrogen cyanide and ACC deaminase production were also found in this strain. Although, CDRTc14 is related to plant pathogens, we neither found a complete pathogenicity island in the genome, nor pathogenicity symptoms on susceptible plant species upon CDRTc14 inoculation. Comparison with other related genomes showed several unique genes involved in abiotic stress tolerance in CDRTc14 like genes responsible for heavy metal and herbicide resistance indicating recent adaptation to plant protection measures applied in vineyards.
Collapse
|
11
|
Rong-Mullins X, Ravishankar A, McNeal KA, Lonergan ZR, Biega AC, Creamer JP, Gallagher JEG. Genetic variation in Dip5, an amino acid permease, and Pdr5, a multiple drug transporter, regulates glyphosate resistance in S. cerevisiae. PLoS One 2017; 12:e0187522. [PMID: 29155836 PMCID: PMC5695762 DOI: 10.1371/journal.pone.0187522] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 10/20/2017] [Indexed: 11/22/2022] Open
Abstract
S. cerevisiae from different environments are subject to a wide range of selective pressures, whether intentional or by happenstance. Chemicals classified by their application, such as herbicides, fungicides and antibiotics, can affect non-target organisms. First marketed as RoundUp™, glyphosate is the most widely used herbicide. In plants, glyphosate inhibits EPSPS, of the shikimate pathway, which is present in many organisms but lacking in mammals. The shikimate pathway produces chorismate which is the precursor to all the aromatic amino acids, para-aminobenzoic acid, and Coenzyme Q10. Crops engineered to be resistant to glyphosate contain a homolog of EPSPS that is not bound by glyphosate. Here, we show that S. cerevisiae has a wide-range of glyphosate resistance. Sequence comparison between the target proteins, i.e., the plant EPSPS and the yeast orthologous protein Aro1, predicted that yeast would be resistant to glyphosate. However, the growth variation seen in the subset of yeast tested was not due to polymorphisms within Aro1, instead, it was caused by genetic variation in an ABC multiple drug transporter, Pdr5, and an amino acid permease, Dip5. Using genetic variation as a probe into glyphosate response, we uncovered mechanisms that contribute to the transportation of glyphosate in and out of the cell. Taking advantage of the natural genetic variation within yeast and measuring growth under different conditions that would change the use of the shikimate pathway, we uncovered a general transport mechanism of glyphosate into eukaryotic cells.
Collapse
Affiliation(s)
- Xiaoqing Rong-Mullins
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
| | - Apoorva Ravishankar
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
| | - Kirsten A. McNeal
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
| | - Zachery R. Lonergan
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
| | - Audrey C. Biega
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
| | - J. Philip Creamer
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
| | - Jennifer E. G. Gallagher
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
| |
Collapse
|
12
|
Sutton KA, Breen J, MacDonald U, Beanan JM, Olson R, Russo TA, Schultz LW, Umland TC. Structure of shikimate kinase, an in vivo essential metabolic enzyme in the nosocomial pathogen Acinetobacter baumannii, in complex with shikimate. ACTA ACUST UNITED AC 2015; 71:1736-44. [PMID: 26249354 DOI: 10.1107/s139900471501189x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 06/22/2015] [Indexed: 11/10/2022]
Abstract
Acinetobacter baumannii is an opportunistic Gram-negative pathogen that is an important cause of healthcare-associated infections exhibiting high mortality rates. Clinical isolates of multidrug-resistant (MDR) and extremely drug-resistant (XDR) A. baumannii strains are increasingly being observed. Compounding this concern is the dearth of new antibacterial agents in late-stage development that are effective against MDR and XDR A. baumannii. As part of an effort to address these concerns, two genes (aroA and aroC) of the shikimate pathway have previously been determined to be essential for the growth and survival of A. baumannii during host infection (i.e. to be essential in vivo). This study expands upon these results by demonstrating that the A. baumannii aroK gene, encoding shikimate kinase (SK), is also essential in vivo in a rat soft-tissue infection model. The crystal structure of A. baumannii SK in complex with the substrate shikimate and a sulfate ion that mimics the binding interactions expected for the β-phosphate of ATP was then determined to 1.91 Å resolution and the enzyme kinetics were characterized. The flexible shikimate-binding domain and LID region are compared with the analogous regions in other SK crystal structures. The impact of structural differences and sequence divergence between SKs from pathogenic bacteria that may influence antibiotic-development efforts is discussed.
Collapse
Affiliation(s)
- Kristin A Sutton
- Hauptman-Woodward Medical Research Institute, Buffalo, NY 14203, USA
| | - Jennifer Breen
- Hauptman-Woodward Medical Research Institute, Buffalo, NY 14203, USA
| | - Ulrike MacDonald
- Department of Medicine and The Witebsky Center for Microbial Pathogenesis, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Janet M Beanan
- Department of Medicine and The Witebsky Center for Microbial Pathogenesis, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Ruth Olson
- Department of Medicine and The Witebsky Center for Microbial Pathogenesis, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Thomas A Russo
- Department of Medicine and The Witebsky Center for Microbial Pathogenesis, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - L Wayne Schultz
- Hauptman-Woodward Medical Research Institute, Buffalo, NY 14203, USA
| | - Timothy C Umland
- Hauptman-Woodward Medical Research Institute, Buffalo, NY 14203, USA
| |
Collapse
|
13
|
Zhang X, Kong W, Wanda SY, Xin W, Alamuri P, Curtiss R. Generation of influenza virus from avian cells infected by Salmonella carrying the viral genome. PLoS One 2015; 10:e0119041. [PMID: 25742162 PMCID: PMC4351096 DOI: 10.1371/journal.pone.0119041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 01/09/2015] [Indexed: 12/14/2022] Open
Abstract
Domestic poultry serve as intermediates for transmission of influenza A virus from the wild aquatic bird reservoir to humans, resulting in influenza outbreaks in poultry and potential epidemics/pandemics among human beings. To combat emerging avian influenza virus, an inexpensive, heat-stable, and orally administered influenza vaccine would be useful to vaccinate large commercial poultry flocks and even migratory birds. Our hypothesized vaccine is a recombinant attenuated bacterial strain able to mediate production of attenuated influenza virus in vivo to induce protective immunity against influenza. Here we report the feasibility and technical limitations toward such an ideal vaccine based on our exploratory study. Five 8-unit plasmids carrying a chloramphenicol resistance gene or free of an antibiotic resistance marker were constructed. Influenza virus was successfully generated in avian cells transfected by each of the plasmids. The Salmonella carrier was engineered to allow stable maintenance and conditional release of the 8-unit plasmid into the avian cells for recovery of influenza virus. Influenza A virus up to 10⁷ 50% tissue culture infective doses (TCID50)/ml were recovered from 11 out of 26 co-cultures of chicken embryonic fibroblasts (CEF) and Madin-Darby canine kidney (MDCK) cells upon infection by the recombinant Salmonella carrying the 8-unit plasmid. Our data prove that a bacterial carrier can mediate generation of influenza virus by delivering its DNA cargoes into permissive host cells. Although we have made progress in developing this Salmonella influenza virus vaccine delivery system, further improvements are necessary to achieve efficient virus production, especially in vivo.
Collapse
Affiliation(s)
- Xiangmin Zhang
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, Michigan, United States of America
- * E-mail:
| | - Wei Kong
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Soo-Young Wanda
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Wei Xin
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Praveen Alamuri
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Roy Curtiss
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Life Science, Arizona State University, Tempe, Arizona, United States of America
| |
Collapse
|
14
|
Staub JM, Brand L, Tran M, Kong Y, Rogers SG. Bacterial glyphosate resistance conferred by overexpression of an E. coli membrane efflux transporter. J Ind Microbiol Biotechnol 2012; 39:641-7. [PMID: 22089966 DOI: 10.1007/s10295-011-1057-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 10/30/2011] [Indexed: 02/03/2023]
Abstract
Glyphosate herbicide-resistant crop plants, introduced commercially in 1994, now represent approximately 85% of the land area devoted to transgenic crops. Herbicide resistance in commercial glyphosate-resistant crops is due to expression of a variant form of a bacterial 5-enolpyruvylshikimate-3-phosphate synthase with a significantly decreased binding affinity for glyphosate at the target site of the enzyme. As a result of widespread and recurrent glyphosate use, often as the only herbicide used for weed management, increasing numbers of weedy species have evolved resistance to glyphosate. Weed resistance is most often due to changes in herbicide translocation patterns, presumed to be through the activity of an as yet unidentified membrane transporter in plants. To provide insight into glyphosate resistance mechanisms and identify a potential glyphosate transporter, we screened Escherichia coli genomic DNA for alternate sources of glyphosate resistance genes. Our search identified a single non-target gene that, when overexpressed in E. coli and Pseudomonas, confers high-level glyphosate resistance. The gene, yhhS, encodes a predicted membrane transporter of the major facilitator superfamily involved in drug efflux. We report here that an alternative mode of glyphosate resistance in E. coli is due to reduced accumulation of glyphosate in cells that overexpress this membrane transporter and discuss the implications for potential alternative resistance mechanisms in other organisms such as plants.
Collapse
Affiliation(s)
- Jeffrey M Staub
- Monsanto Company, 700 Chesterfield Parkway North, St. Louis, MO 63017, USA.
| | | | | | | | | |
Collapse
|
15
|
Haghani K, Salmanian AH, Ranjbar B, Zakikhan-Alang K, Khajeh K. Comparative studies of wild type Escherichia coli 5-enolpyruvylshikimate 3-phosphate synthase with three glyphosate-insensitive mutated forms: activity, stability and structural characterization. BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1784:1167-75. [PMID: 18567546 DOI: 10.1016/j.bbapap.2007.07.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Revised: 07/22/2007] [Accepted: 07/23/2007] [Indexed: 10/22/2022]
Abstract
5-Enolpyruvylshikimate 3-phosphate (EPSP) synthase is an essential enzyme of the shikimate pathway and is the target for the herbicide, glyphosate. Several glyphosate-insensitive forms of Escherichia coli EPSP synthase had been reported in the literatures. In the present study the function and structure of wild type enzyme and three different mutated variants (G96A, A183T and G96A/A183T) were compared. Results showed that G96A and G96A/A183T variants are insensitive to glyphosate but display a 31- and 8-fold lower affinity for phosphoenolpyruvate (PEP) as substrate, respectively. In addition, chemical stability of the enzyme variants against Gdn-HCl revealed more stability of the wild type and G96A variant when compared to the G96A/A183T and A183T variants. Comparison of the enzymes containing Ala183Thr replacement with the wild type showed a lower resistance to digestion by the proteases. Moreover, with respect to fluorescence quenching by acrylamide, A183T and G96A/A183T variants were characterized by a higher structural flexibility and more exposure of tryptophan residues to the solvent. In addition, based on the results of circular dichroism and intrinsic fluorescence studies, these two variants represent a significant decrease of secondary structures and changes in the tertiary structure as compared to the wild type and the G96A variant.
Collapse
Affiliation(s)
- Karimeh Haghani
- Department of Biochemistry and Biophysics, Faculty of Science, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran
| | | | | | | | | |
Collapse
|
16
|
Marques MR, Vaso A, Neto JR, Fossey MA, Oliveira JS, Basso LA, dos Santos DS, de Azevedo Junior WF, Palma MS. Dynamics of glyphosate-induced conformational changes of Mycobacterium tuberculosis 5-enolpyruvylshikimate-3-phosphate synthase (EC 2.5.1.19) determined by hydrogen-deuterium exchange and electrospray mass spectrometry. Biochemistry 2008; 47:7509-22. [PMID: 18558720 DOI: 10.1021/bi800134y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) catalyzes the reaction between shikimate 3-phosphate and phosphoenolpyruvate to form 5-enolpyruvylshikimate 3-phosphate, an intermediate in the shikimate pathway, which leads to the biosynthesis of aromatic amino acids. EPSPS exists in an open conformation in the absence of substrates and/or inhibitors and in a closed conformation when bound to the substrate and/or inhibitor. In the present report, the H/D exchange properties of EPSPS from Mycobacterium tuberculosis ( Mt) were investigated for both enzyme conformations using ESI mass spectrometry and circular dichroism (CD). When the conformational changes identified by H/D exchanges were mapped on the 3-D structure, it was observed that the apoenzyme underwent extensive conformational changes due to glyphosate complexation, characterized by an increase in the content of alpha-helices from 40% to 57%, while the beta-sheet content decreased from 30% to 23%. These results indicate that the enzyme underwent a series of rearrangements of its secondary structure that were accompanied by a large decrease in solvent access to many different regions of the protein. This was attributed to the compaction of 71% of alpha-helices and 57% of beta-sheets as a consequence of glyphosate binding to the enzyme. Apparently, MtEPSPS undergoes a series of inhibitor-induced conformational changes, which seem to have caused synergistic effects in preventing solvent access to the core of molecule, especially in the cleft region. This may be part of the mechanism of inhibition of the enzyme, which is required to prevent the hydration of the substrate binding site and also to induce the cleft closure to avoid entrance of the substrates.
Collapse
Affiliation(s)
- Maurício R Marques
- Laboratory of Structural Biology and Zoochemistry, CEIS/Department of Biology, Institute of Biosciences, UNESP, Rio Claro, SP 13506-900, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Dun BQ, Wang XJ, Lu W, Zhao ZL, Hou SN, Zhang BM, Li GY, Evans TC, Xu MQ, Lin M. Reconstitution of glyphosate resistance from a split 5-enolpyruvyl shikimate-3-phosphate synthase gene in Escherichia coli and transgenic tobacco. Appl Environ Microbiol 2007; 73:7997-8000. [PMID: 17951442 PMCID: PMC2168149 DOI: 10.1128/aem.00956-07] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2007] [Accepted: 10/10/2007] [Indexed: 11/20/2022] Open
Abstract
A highly N-phosphonomethylglycine (glyphosate)-resistant Pseudomonas fluorescens G2 5-enolpyruvyl shikimate-3-phosphate synthase (EPSPS) was mapped to identify potential split sites using a transposon-based linker-scanning procedure. Intein-mediated protein complementation was used to reconstitute glyphosate resistance from the genetically divided G2 EPSPS gene in Escherichia coli strain ER2799 and transgenic tobacco.
Collapse
Affiliation(s)
- Bao-Qing Dun
- Biotechnology Research Institute, Chinese Academy of Agriculture Sciences, Beijing 100081, China.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Dun B, Lu W, Zhang W, Ping S, Wang X, Chen M, Xu Y, Jin D, Wang J, Zhao Z, Liang A, Hou S, Xu MQ, Lin M. Reconstruction of enzymatic activity from split genes encoding glyphosate-tolerant EPSPS protein of Psedomonas fluorescens G2 strain by intein mediated protein complementation. CHINESE SCIENCE BULLETIN-CHINESE 2006. [DOI: 10.1007/s11434-006-2017-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
19
|
Lessard PA, Kulaveerasingam H, York GM, Strong A, Sinskey AJ. Manipulating gene expression for the metabolic engineering of plants. Metab Eng 2002; 4:67-79. [PMID: 11800576 DOI: 10.1006/mben.2001.0210] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Introducing and expressing foreign genes in plants present many technical challenges that are not encountered with microbial systems. This review addresses the variety of issues that must be considered and the variety of options that are available, in terms of choosing transformation systems and designing recombinant transgenes to ensure appropriate expression in plant cells. Tissue specificity and proper developmental regulation, as well as proper subcellular localization of products, must be dealt with for successful metabolic engineering in plants..
Collapse
Affiliation(s)
- Philip A Lessard
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | | | | | | |
Collapse
|
20
|
Duncan K, Lewendon A, Coggins JR. The complete amino acid sequence ofEscherichia coli5-enolpyruvylshikimate 3-phosphate synthase. FEBS Lett 2001. [DOI: 10.1016/0014-5793(84)81368-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
21
|
Sost D, Schulz A, Amrhein N. Characterization of a glyphosate-insensitive 5-enolpyruvylshikimic acid-3-phosphate synthase. FEBS Lett 2001. [DOI: 10.1016/0014-5793(84)81054-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
22
|
Krekel F, Oecking C, Amrhein N, Macheroux P. Substrate and inhibitor-induced conformational changes in the structurally related enzymes UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) and 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS). Biochemistry 1999; 38:8864-78. [PMID: 10413459 DOI: 10.1021/bi990412o] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) and 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS) have both a unique three-dimensional topology and overall reaction mechanism in common. In the case of MurA, the substrate-free, unliganded protein exhibits an "open" conformation. Upon binding of substrates, the protein forms a much more tightly packed so-called "closed" form following an induced fit mechanism. In this closed form, the substrates are properly positioned for catalysis. On the basis of the structural and mechanistic similarities of MurA and EPSPS, a similar conformational change is likely to occur in EPSPS to generate a catalytically competent active site. However, there is currently little experimental evidence available to support the occurrence of such a conformational change in EPSPS. Using limited tryptic digestion of MurA,(1) it could be shown that formation of the "closed" conformation of MurA is accompanied by a marked increase of stability toward proteolytic degradation. Formation of the closed conformation was achieved by addition of either an excess of both substrates or the sugar nucleotide substrate in conjunction with the antibiotic fosfomycin. Analysis of the MurA tryptic fragments by MALDI-TOF mass spectrometry demonstrates that the protection of the protein in either case is caused by (1) a specific shielding of regions thereby becoming less accessible as a result of the conformational change, and (2) an unspecific overall protection of the whole protein due to an apparently reduced flexibility of the peptide backbone in the binary and ternary complexes. The establishment of methods to describe the effects of tryptic digestion on MurA under various conditions was then extended to EPSPS. Although EPSPS was found to be much more stable toward proteolysis than MurA, the presence of shikimate 3-phosphate (S3P) and the inhibitor glyphosate led to a pronounced suppression of proteolytic degradation. When unliganded EPSPS was treated with trypsin, three of the peptide fragments obtained could be identified by mass spectrometry. Two of these are located in a region corresponding to the "catalytic" loop in MurA which participates in the conformational change. This indicates a conformational change in EPSPS, similar to the one observed in MurA, leading to the protection mentioned above. Corroborating evidence was obtained using a conformational sensitive monoclonal antibody against EPSPS which showed a 20-fold reduced affinity toward the protein complexed with S3P and glyphosate as compared to the unliganded enzyme.
Collapse
Affiliation(s)
- F Krekel
- Institut für Pflanzenwissenschaften, ETH-Zürich, Switzerland
| | | | | | | |
Collapse
|
23
|
Daniell H, Datta R, Varma S, Gray S, Lee SB. Containment of herbicide resistance through genetic engineering of the chloroplast genome. Nat Biotechnol 1998; 16:345-8. [PMID: 9555724 PMCID: PMC5522713 DOI: 10.1038/nbt0498-345] [Citation(s) in RCA: 221] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glyphosate is a potent herbicide. It works by competitive inhibition of the enzyme 5-enol-pyruvyl shikimate-3-phosphate synthase (EPSPS), which catalyzes an essential step in the aromatic amino acid biosynthetic pathway. We report the genetic engineering of herbicide resistance by stable integration of the petunia EPSPS gene into the tobacco chloroplast genome using the tobacco or universal vector. Southern blot analysis confirms stable integration of the EPSPS gene into all of the chloroplast genomes (5000-10,000 copies per cell) of transgenic plants. Seeds obtained after the first self-cross of transgenic plants germinated and grew normally in the presence of the selectable marker, whereas the control seedlings were bleached. While control plants were extremely sensitive to glyphosate, transgenic plants survived sprays of high concentrations of glyphosate. Chloroplast transformation provides containment of foreign genes because plastid transgenes are not transmitted by pollen. The escape of foreign genes via pollen is a serious environmental concern in nuclear transgenic plants because of the high rates of gene flow from crops to wild weedy relatives.
Collapse
Affiliation(s)
- H Daniell
- Department of Botany and Microbiology, Auburn University, AL 36849-5407, USA.
| | | | | | | | | |
Collapse
|
24
|
Shah A, Font JL, Miller MJ, Ream JE, Walker MC, Sikorski JA. New aromatic inhibitors of EPSP synthase incorporating hydroxymalonates as novel 3-phosphate replacements. Bioorg Med Chem 1997; 5:323-34. [PMID: 9061197 DOI: 10.1016/s0968-0896(96)00239-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A new, aromatic analogue of the EPSP synthase enzyme reaction intermediate 1 has been identified, which contains a 3-hydroxymalonate moiety in place of the usual 3-phosphate group. This simplified inhibitor was readily prepared in five steps from ethyl 3,4-dihydroxybenzoate. The resulting tetrahedral intermediate mimic 9 is an effective, competitive inhibitor versus S3P with an apparent Ki of 0.57 +/- 0.06 microM. This result demonstrates that 3-hydroxymalonates exhibit potencies comparable to aromatic inhibitors containing the previously identified 3-malonate ether replacements and can thus function as suitable 3-phosphate mimics in this system. These new compounds provide another example in which a simple benzene ring can be used effectively in place of the more complex shikimate ring in the design of EPSP synthase inhibitors. Furthermore, the greater potency of 9 versus the glycolate derivative 10 and the 5-deoxy-analog 11, again confirms the requirement for multiple anionic charges at the dihydroxybenzoate 5-position in order to attain effective inhibition of this enzyme.
Collapse
Affiliation(s)
- A Shah
- Ceregen Corporate Research, Unit of Monsanto Company, St. Louis, MO 63198, USA
| | | | | | | | | | | |
Collapse
|
25
|
Marzabadi MR, Gruys KJ, Pansegrau PD, Walker MC, Yuen HK, Sikorski JA. An EPSP synthase inhibitor joining shikimate 3-phosphate with glyphosate: synthesis and ligand binding studies. Biochemistry 1996; 35:4199-210. [PMID: 8672456 DOI: 10.1021/bi9521349] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A novel EPSP synthase inhibitor 4 has been designed and synthesized to probe the configurational details of glyphosate recognition in its herbicidal ternary complex with enzyme and shikimate 3-phosphate (S3P). A kinetic evaluation of the new 3-dephospho analog 12, as well as calorimetric and (31)P NMR spectroscopic studies of enzyme-bound 4, now provides a more precise quantitative definition for the molecular interactions of 4 with this enzyme. The very poor binding, relative to 4, displayed by the 3-dephospho analog 12 is indicative that 4 has a specific interaction with the S3P site. A comparison of Ki(calc) for 12 versus the Ki(app) for 4 indicates that the 3-phosphate group in 4 contributes about 4.8 kcal/mol to binding. This compares well with the 5.2 kcal/mol which the 3-phosphate group in S3P contributes to binding. Isothermal titration calorimetry demonstrates that 4 binds to free enzyme with an observed Kd of 0.53 +/- 0.04 microM. As such, 4 binds only 3-fold weaker than glyphosate and about 150-fold better than N-methylglyphosate. Consequently, 4 represents the most potent N-alkylglyphosate derivative identified to date. However, the resulting thermodynamic binding parameters clearly demonstrate that the formation of EPSPS x 4 is entropy driven like S3P. The binding characteristics of 4 are fully consistent with a primary interaction localized at the S3P subsite. Furthermore, (31)P NMR studies of enzyme-bound 4 confirm the expected interaction at the shikimate 3-phosphate site. However, the chemical shift observed for the phosphonate signal of EPSPS x 4 is in the opposite direction than that observed previously when glyphosate binds with enzyme and S3P. Therefore, when 4 occupies the S3P binding site, there is incomplete overlap at the glyphosate phosphonate subsite. As a glyphosate analog inhibitor, the potency of 4 most likely arises from predominant interactions which occur outside the normal glyphosate binding site. Consequently, 4 is best described as an S3P-based substrate-analog inhibitor. These combined results corroborate the previous kinetic model [Gruys, K. J., Marzabadi, M. R., Pansegrau, P. D., & Sikorski, J. A. (1993) Arch. Biochem. Biophys. 304, 345-351], which suggested that 4 interacts well with the S3P subsite but has little, if any, interaction at the expected glyphosate phosphonate or phosphoenolpyruvate-Pi subsites.
Collapse
Affiliation(s)
- M R Marzabadi
- Ceregen and Monsanto Corporate Research, Units of Monsanto Company, St. Louis, Missouri 63198
| | | | | | | | | | | |
Collapse
|
26
|
Miller MJ, Cleary DG, Ream JE, Snyder KR, Sikorski JA. New EPSP synthase inhibitors: synthesis and evaluation of an aromatic tetrahedral intermediate mimic containing a 3-malonate ether as a 3-phosphate surrogate. Bioorg Med Chem 1995; 3:1685-92. [PMID: 8770393 DOI: 10.1016/0968-0896(95)00156-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A new analog of the EPSP synthase enzyme reaction intermediate 1, containing a 3-malonate ether moiety in place of the usual 3-phosphate group, was synthesized from 3,5-dihydroxybenzoic acid. This simple, synthetically accessible aromatic compound (5) is an effective competitive inhibitor versus S3P with an apparent Ki of 1.3 +/- 0.22 microM. This result demonstrates that a simple benzene ring can be a suitable achiral substitute for the more complex shikimate ring in the design of EPSP synthase inhibitors. Furthermore, the greater potency of 5 versus the phenol 6, glycolate 7 and the gallic acid analog 8 demonstrates the requirement for multiple anionic charges at the dihydroxybenzoate 5-position in order to attain effective inhibition of this enzyme. However, this 3-malonate ether substituted compound was at least 10-fold less effective as a bisubstrate inhibitor than the corresponding 3-phosphate. This suggests that tetrahedral intermediate mimics possessing a 3-malonate ether moiety are less effective than their corresponding 3-phosphates in accessing the optimal enzyme conformation stabilizing 1.
Collapse
Affiliation(s)
- M J Miller
- Ceregen Corporate Research, Units of Monsanto Company, St Louis, MO 63198, USA
| | | | | | | | | |
Collapse
|
27
|
Peñaloza-Vazquez A, Mena GL, Herrera-Estrella L, Bailey AM. Cloning and sequencing of the genes involved in glyphosate utilization by Pseudomonas pseudomallei. Appl Environ Microbiol 1995; 61:538-43. [PMID: 7574593 PMCID: PMC167315 DOI: 10.1128/aem.61.2.538-543.1995] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Thirty-four strains of Pseudomonas pseudomallei isolated from soil were selected for their ability to degrade the phosphonate herbicide glyphosate. All strains tested were able to grow on glyphosate as the only phosphorus source without the addition of aromatic amino acids. One of these strains, P. pseudomallei 22, showed 50% glyphosate degradation in 40 h in glyphosate medium. From a genomic library of this strain constructed in pUC19, we have isolated a plasmid carrying a 3.0-kb DNA fragment which confers to E. coli the ability to use glyphosate as a phosphorus source. This 3.0-kb DNA fragment from P. pseudomallei contained two open reading frames (glpA and glpB) which are involved in glyphosate tolerance and in the modification of glyphosate to a substrate of the Escherichia coli carbon-phosphorus lyase. glpA exhibited significant homology with the E. coli hygromycin phosphotransferase gene. It was also found that the hygromycin phosphotransferase genes from both P. pseudomallei and E. coli confer tolerance to glyphosate.
Collapse
Affiliation(s)
- A Peñaloza-Vazquez
- Departamento de Ingeniería Genética de Plantas CINVESTAV-IPN Unidad Irapuato, Mexico
| | | | | | | |
Collapse
|
28
|
Miller MJ, Ream JE, Walker MC, Sikorski JA. Functionalized 3,5-dihydroxybenzoates as potent novel inhibitors of EPSP synthase. Bioorg Med Chem 1994; 2:331-8. [PMID: 7922144 DOI: 10.1016/s0968-0896(00)82189-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Aromatic analogues of the EPSP synthase enzyme substrate (S3P), reaction intermediate (1), and product (EPSP) were synthesized from 3,5-dihydroxybenzoic acid and were evaluated as inhibitors of E. coli EPSP synthase. These simple, synthetically accessible aromatic analogues are highly effective competitive inhibitors versus S3P with an apparent Ki for the tetrahedral intermediate analogue 4 of 160 +/- 40 nM. This demonstrates that a simple benzene ring is a quite suitable substitute for the complex shikimate ring in the design of EPSP synthase inhibitors.
Collapse
Affiliation(s)
- M J Miller
- Life Sciences Research Center, Monsanto Company, St. Louis, Missouri 63198
| | | | | | | |
Collapse
|
29
|
Ream JE, Yuen HK, Frazier RB, Sikorski JA. EPSP synthase: binding studies using isothermal titration microcalorimetry and equilibrium dialysis and their implications for ligand recognition and kinetic mechanism. Biochemistry 1992; 31:5528-34. [PMID: 1610798 DOI: 10.1021/bi00139a015] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Isothermal titration calorimetry measurements are reported which give important new binding constant (Kd) information for various substrate and inhibitor complexes of Escherichia coli EPSP synthase (EPSPS). The validity of this technique was first verified by determining Kd's for the known binary complex with the substrate, shikimate 3-phosphate (S3P), as well as the herbicidal ternary complex with S3P and glyphosate (EPSPS.S3P.glyphosate). The observed Kd's agreed very well with those from previous independently determined kinetic and fluorescence binding measurements. Further applications unequivocally demonstrate for the first time a fairly tight interaction between phosphoenolpyruvate (PEP) and free enzyme (Kd = 390 microM) as well as a correspondingly weak affinity for glyphosate (Kd = 12 mM) alone with enzyme. The formation of the EPSPS.PEP binary complex was independently corroborated using equilibrium dialysis. These results strongly suggest that S3P synergizes glyphosate binding much more effectively than it does PEP binding. These observations add important new evidence to support the hypothesis that glyphosate acts as a transition-state analogue of PEP. However, the formation of a catalytically productive PEP binary complex is inconsistent with the previously reported compulsory binding order process required for catalysis and has led to new studies which completely revise the overall EPSPS kinetic mechanism. A previously postulated ternary complex between S3P and inorganic phosphate (EPSPS.S3P.Pi, Kd = 4 mM) was also detected for the first time. Quantitative binding enthalpies and entropies were also determined for each ligand complex from the microcalorimetry data. These values demonstrate a clear difference in thermodynamic parameters for recognition at the S3P site versus those observed for the PEP, Pi, and glyphosate sites.
Collapse
Affiliation(s)
- J E Ream
- New Products Division, Monsanto Agricultural Company, St. Louis, Missouri 63198
| | | | | | | |
Collapse
|
30
|
Gruys KJ, Walker MC, Sikorski JA. Substrate synergism and the steady-state kinetic reaction mechanism for EPSP synthase from Escherichia coli. Biochemistry 1992; 31:5534-44. [PMID: 1344882 DOI: 10.1021/bi00139a016] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Previous studies of Escherichia coli 5-enolpyruvoylshikimate-3-phosphate synthase (EPSPS, EC 2.5.1.19) have suggested that the kinetic reaction mechanism for this enzyme in the forward direction is equilibrium ordered with shikimate 3-phosphate (S3P) binding first followed by phosphoenolpyruvate (PEP). Recent results from this laboratory, however, measuring direct binding of PEP and PEP analogues to free EPSPS suggest more random character to the enzyme. Steady-state kinetic and spectroscopic studies presented here indicate that E. coli EPSPS does indeed follow a random kinetic mechanism. Initial velocity studies with S3P and PEP show competitive substrate inhibition by PEP added to a normal intersecting pattern. Substrate inhibition is proposed to occur by competitive binding of PEP at the S3P site [Ki(PEP) = 6-8 mM]. To test for a productive EPSPS.PEP binary complex, the reaction order of EPSPS was evaluated with shikimic acid and PEP as substrates. The mechanism for this reaction is equilibrium ordered with PEP binding first giving a Kia value for PEP in agreement with the independently measured Kd of 0.39 mM (shikimate Km = 25 mM). Results from this study also show that the 3-phosphate moiety of S3P offers 8.7 kcal/mol in binding energy versus a hydroxyl in this position. Over 60% of this binding energy is expressed in binding of substrate to enzyme rather than toward increasing kcat. Glyphosate inhibition of shikimate turnover was poor with approximately 8 x 10(4) loss in binding capacity compared to the normal reaction, consistent with the independently measured Kd of 12 mM for the EPSPS.glyphosate binary complex. The EPSPS.glyphosate complex induces shikimate binding, however, by a factor of 7 greater than EPSPS.PEP. Carboxyallenyl phosphate and (Z)-3-fluoro-PEP were found to be strong inhibitors of the enzyme that have surprising affinity for the S3P binding domain in addition to the PEP site as measured both kinetically and by direct observation with 31P NMR. The collective data indicate that the true kinetic mechanism for EPSPS in the forward direction is random with synergistic binding occurring between substrates and inhibitors. The synergism explains how the mechanism can be random with S3P and PEP, but yet equilibrium ordered with PEP binding first for shikimate turnover. Synergism also accounts for how glyphosate can be a strong inhibitor of the normal reaction, but poor versus shikimate turnover.
Collapse
Affiliation(s)
- K J Gruys
- New Products Division, Monsanto Agricultural Company, St. Louis, Missouri 63167
| | | | | |
Collapse
|
31
|
Stallings WC, Abdel-Meguid SS, Lim LW, Shieh HS, Dayringer HE, Leimgruber NK, Stegeman RA, Anderson KS, Sikorski JA, Padgette SR, Kishore GM. Structure and topological symmetry of the glyphosate target 5-enolpyruvylshikimate-3-phosphate synthase: a distinctive protein fold. Proc Natl Acad Sci U S A 1991; 88:5046-50. [PMID: 11607190 PMCID: PMC51804 DOI: 10.1073/pnas.88.11.5046] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
5-enol-Pyruvylshikimate-3-phosphate synthase (EPSP synthase; phosphoenolpyruvate:3-phosphoshikimate 1-carboxyvinyltransferase, EC 2.5.1.19) is an enzyme on the pathway toward the synthesis of aromatic amino acids in plants, fungi, and bacteria and is the target of the broad-spectrum herbicide glyphosate. The three-dimensional structure of the enzyme from Escherichia coli has been determined by crystallographic techniques. The polypeptide backbone chain was traced by examination of an electron density map calculated at 3-A resolution. The two-domain structure has a distinctive fold and appears to be formed by 6-fold replication of a protein folding unit comprising two parallel helices and a four-stranded sheet. Each domain is formed from three of these units, which are related by an approximate threefold symmetry axis; in each domain three of the helices are completely buried by a surface formed from the three beta-sheets and solvent-accessible faces of the other three helices. The domains are related by an approximate dyad, but in the present crystals the molecule does not display pseudo-symmetry related to the symmetry of point group 32 because its approximate threefold axes are almost normal. A possible relation between the three-dimensional structure of the protein and the linear sequence of its gene will be described. The topological threefold symmetry and orientation of each of the two observed globular domains may direct the binding of substrates and inhibitors by a helix macrodipole effect and implies that the active site is located near the interdomain crossover segments. The structure also suggests a rationale for the glyphosate tolerance conferred by sequence alterations.
Collapse
Affiliation(s)
- W C Stallings
- Monsanto Corporate Research and Technology Division of Monsanto Agricultural Company, Monsanto Company, St. Louis, MO 63198, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
|
33
|
Sost D, Amrhein N. Substitution of Gly-96 to Ala in the 5-enolpyruvylshikimate-3-phosphate synthase of Klebsiella pneumoniae results in a greatly reduced affinity for the herbicide glyphosate. Arch Biochem Biophys 1990; 282:433-6. [PMID: 2241161 DOI: 10.1016/0003-9861(90)90140-t] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The aroA gene of Klebsiella pneumoniae encoding the shikimate pathway enzyme 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase, which is the target of the herbicide glyphosate, was cloned and sequenced from both the wild-type and the glyphosate-resistant mutant K. pneumoniae K1, which possesses a glyphosate-insensitive EPSP synthase. Both genes were expressed in Escherichia coli and were capable of complementing an auxotrophic aroA mutation. The transformed cells showed increased tolerance to glyphosate due to the overproduction of either the mutant or the wild type EPSP synthase. Nucleotide sequence analysis of the K. pneumoniae aroA gene indicated a protein-coding region of 427 amino acids with a derived Mr for the EPSP synthase of 45,976. Comparison of the two aroA alleles showed a single base change resulting in a substitution of Gly-96 to Ala in the deduced amino acid sequence. By comparison with other known EPSP synthase sequences the mutation was shown to be located in a highly conserved region, indicating that this region is essential for the binding of the herbicide glyphosate.
Collapse
Affiliation(s)
- D Sost
- Lehrstuhl für Pflanzenphysiologie, Ruhr-Universität Bochum, Federal Republic of Germany
| | | |
Collapse
|
34
|
Anderson KS, Johnson KA. "Kinetic competence" of the 5-enolpyruvoylshikimate-3-phosphate synthase tetrahedral intermediate. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39398-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
35
|
Affiliation(s)
- R Bentley
- Department of Chemistry, University of Sheffield, U.K
| |
Collapse
|
36
|
Barlow PN, Appleyard RJ, Wilson JO, Evans JN. Direct observation of the enzyme-intermediate complex of 5-enolpyruvylshikimate-3-phosphate synthase by 13C NMR spectroscopy. Biochemistry 1989; 28:7985-91. [PMID: 2557890 DOI: 10.1021/bi00446a003] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The interaction of 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase, 4,5-dideoxyshikimate 3-phosphate (ddS3P), and [2-13C]-and [3-13C]phosphoenolpyruvate (PEP) has been examined by 13C NMR spectroscopy. Although no resonances due to a dead-end intermediate complex could be detected, an enzyme active site specific formation of pyruvate was observed. The interaction of EPSP synthase with shikimate 3-phosphate (S3P) and [2-13C]- or [3-13C]PEP has been examined by 13C NMR spectroscopy. With [2-13C]PEP, in addition to the resonances due to [2-13C]PEP and [8-13C]EPSP, new resonances appeared at 164.8, 110.9, and 107.2 ppm. The resonance at 164.8 ppm has been assigned to enzyme-bound EPSP. The resonance at 110.9 ppm has been assigned to C-8 of an enzyme-free tetrahedral intermediate of the sort originally proposed by Levin and Sprinson [Levin, J. G., & Sprinson, D. B. (1964) J. Biol. Chem. 239, 1142-1150] and recently independently observed by Anderson et al. [Anderson, K. S., Sikorski, J. A., Benesi, A. J., & Johnson, K. A. (1988) J. Am. Chem. Soc. 110, 6577-6579]. The resonance at 107.2 ppm has been assigned to an enzyme-bound intermediate whose structure is closely related to that of the tetrahedral intermediate. With [3-13C]PEP, new resonances appeared at 88.9, 26.2, 25.5, and 24.5 ppm. The resonance at 88.9 ppm has been assigned to enzyme-bound EPSP. The resonance at 26.2 ppm, which was found to correlate with 1.48 ppm by isotope-edited multiple quantum coherence 1H NMR spectroscopy, has been assigned to the methyl group 4-hydroxy-4-methylketoglutarate.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- P N Barlow
- Dyson Perrins Laboratory, University of Oxford, U.K
| | | | | | | |
Collapse
|
37
|
Olins PO, Devine CS, Rangwala SH, Kavka KS. The T7 phage gene 10 leader RNA, a ribosome-binding site that dramatically enhances the expression of foreign genes in Escherichia coli. Gene 1988; 73:227-35. [PMID: 3072257 DOI: 10.1016/0378-1119(88)90329-0] [Citation(s) in RCA: 134] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Expression of foreign genes in Escherichia coli requires the juxtaposition of prokaryotic transcription and translation elements with a coding region for the foreign gene. Commonly, this results in only modest expression of the foreign gene product. Here we describe a novel ribosome-binding site (RBS; phage T7 'gene 10 leader') which is able to drive the translation of several foreign genes. This RBS dramatically enhanced the translation efficiency of all the genes we have tested to date, and was particularly effective for foreign genes. The enhanced expression was often more than 40-fold greater than that obtained using a 'consensus' RBS. A general plasmid vector has been constructed, incorporating the T7 gene 10 leader sequence, which allows the facile expression of important gene products. In this report we demonstrate the application of this system for the high-level expression of plant, mammalian and bacterial proteins in E. coli.
Collapse
Affiliation(s)
- P O Olins
- Biological Sciences Department, Monsanto Company, St. Louis, MO 63198
| | | | | | | |
Collapse
|
38
|
Padgette SR, Smith CE, Huynh QK, Kishore GM. Arginine chemical modification of Petunia hybrida 5-enol-pyruvylshikimate-3-phosphate synthase. Arch Biochem Biophys 1988; 266:254-62. [PMID: 3178227 DOI: 10.1016/0003-9861(88)90256-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Reaction of Petunia hybrida 5-enol-pyruvylshikimate-3-phosphate synthase (EPSPS) with the arginine reagents phenylglyoxal (PGO) and p-hydroxyphenylglyoxal (HPGO) leads to inactivation of the enzyme. Inactivation with HPGO leads to modification of approximately 3 mol of arginine per mole of enzyme. The modification reaction follows pseudo-first-order kinetics with a t1/2 of 1 min at 5 mM p-hydroxyphenylglyoxal in 0.1 M triethanolamine HCl, pH 7.8. By titration of HPGO-modified enzyme with 5,5'-bis(dithio-2-nitrobenzoic acid), the possibility of cysteine modification by the arginine reagent was ruled out. While shikimate 3-phosphate (S3P) afforded partial protection to the enzyme against inactivation by HPGO, complete protection could be obtained by using a mixture of S3P and glyphosate. Under the latter conditions, only 1 mol arginine was modified per mole of enzyme. This pattern of reactivity suggests that two arginines may be involved in the binding of S3P and glyphosate to EPSP synthase. A third reactive arginine appears to be nonessential for EPSPS activity. Labeling of EPSP synthase with [14C]phenylglyoxal, peptic digestion, HPLC mapping, and amino acid sequencing indicate that Arg-28 and Arg-131 are two of the reactive arginines labeled with [14C]PGO.
Collapse
Affiliation(s)
- S R Padgette
- Plant Molecular Biology and Chemistry Groups, Biological Sciences, Monsanto
| | | | | | | |
Collapse
|
39
|
Anderson KS, Sikorski JA, Johnson KA. A tetrahedral intermediate in the EPSP synthase reaction observed by rapid quench kinetics. Biochemistry 1988; 27:7395-406. [PMID: 3061457 DOI: 10.1021/bi00419a034] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Direct evidence for an enzyme-bound intermediate in the EPSP synthase reaction pathway has been obtained by rapid chemical quench-flow studies. The transient-state kinetic analysis has led to the following complete scheme: (formula; see text) Values for all 12 rate constants were obtained. Substrate trapping experiments in the forward and reverse reactions established the kinetically preferred order of binding and release of substrates and products and showed that shikimate 3-phosphate (S3P) and 5-enolpyruvoylshikimate 3-phosphate (EPSP) dissociate at rates greater than turnover in each direction. Pre-steady-state bursts of product formation were observed in the reaction in each direction indicating a rate-limiting step following catalysis. Single turnover experiments with enzyme in excess over substrate demonstrated the formation of a transient intermediate in both the forward and reverse reactions. In these experiments, the enzymatic reaction was observed by employing a radiolabel in the enol moiety of either phosphoenol pyruvate (PEP) or EPSP. The separation and quantitation of reaction products were accomplished by HPLC monitoring radioactivity. The intermediate was observed as the transient production of radiolabeled pyruvate, formed due to the breakdown of the intermediate in the acid quench used to stop the reaction. The intermediate was observed within 5-10 ms after the substrates were mixed with enzyme and decayed in a reaction paralleling the formation of product in each direction. Thus, the kinetics demonstrate directly the kinetic competence of the presumed intermediate. No pyruvate was formed, on a time scale which is relevant to catalysis, after incubation of the enzyme with dideoxy-S3P and PEP or with EPSP in the absence of phosphate; and so, the intermediate does not accumulate under these conditions. The intermediate broke down to form PEP and EPSP in addition to pyruvate when the reaction was quenched with base rather than acid; therefore, the intermediate must contain the elements of each product. Other experiments were designed to measure directly the phosphate binding rate and further constrain the PEP binding rate. The overall solution equilibrium constant in the forward direction was determined to be 180 by quantitation of radiolabeled reactants and products in equilibrium after incubation with a low enzyme concentration. The internal, active site equilibrium constant was obtained by incubation of radiolabeled S3P with excess enzyme and high concentrations of phosphate and PEP to provide the ratio of [EPSP]/[S3P] = 2.3, which is largely a measure of K4.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- K S Anderson
- Monsanto Agricultural Company, A Unit of Monsanto Company, St. Louis, Missouri 63167
| | | | | |
Collapse
|
40
|
Fitzgibbon J, Braymer HD. Phosphate starvation induces uptake of glyphosate by Pseudomonas sp. strain PG2982. Appl Environ Microbiol 1988; 54:1886-8. [PMID: 2458066 PMCID: PMC202767 DOI: 10.1128/aem.54.7.1886-1888.1988] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Pseudomonas sp. strain PG2982 has the ability to use the phosphonate herbicide, glyphosate, as a sole phosphorus source (J. K. Moore, H. D. Braymer, and A. D. Larson, Appl. Environ. Microbiol. 46:316-320, 1983). Glyphosate uptake is maximal in the late log phase of growth and is induced by phosphate starvation. Uptake is inhibited by phosphate and arsenate, but not by the amino acids glycine and sarcosine. The Km and Vmax for glyphosate uptake were calculated to be 23 microM and 0.97 nmol/mg (dry weight) per min, respectively. A phosphate transport system with a broad substrate specificity may be responsible for glyphosate uptake.
Collapse
Affiliation(s)
- J Fitzgibbon
- Department of Microbiology, Louisiana State University, Baton Rouge 70803
| | | |
Collapse
|
41
|
Haahtela K, Kilpi S, Kari K. Effects of phenoxy acid herbicides and glyphosate on nitrogenase activity (acetylene reduction) in root-associated Azospirillum, Enterobacter and Klebsiella. FEMS Microbiol Lett 1988. [DOI: 10.1111/j.1574-6968.1988.tb02655.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
42
|
Padgette SR, Huynh QK, Aykent S, Sammons RD, Sikorski JA, Kishore GM. Identification of the reactive cysteines of Escherichia coli 5-enolpyruvylshikimate-3-phosphate synthase and their nonessentiality for enzymatic catalysis. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)77947-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
43
|
Padgette SR, Huynh QK, Borgmeyer J, Shah DM, Brand LA, Biest Re D, Bishop BF, Rogers SG, Fraley RT, Kishore GM. Bacterial expression and isolation of Petunia hybrida 5-enol-pyruvylshikimate-3-phosphate synthase. Arch Biochem Biophys 1987; 258:564-73. [PMID: 3314713 DOI: 10.1016/0003-9861(87)90378-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
5-enol-Pyruvylshikimate-3-phosphate synthase (EPSP synthase, EPSPS), an in vivo enzyme target of the herbicide glyphosate (N-phosphonomethyl glycine), was purified from a Petunia hybrida suspension culture line, MP4-G, by a small-scale high-performance chromatographic purification procedure. The cDNA encoding the mature petunia EPSPS (lacking the chloroplast transit sequence) was cloned into a plasmid, pMON342, for expression in Escherichia coli. This clone complemented the EPSPS deficiency of an E. coli aroA- mutant, and the plant enzyme constituted approximately 1% of the total extractable protein. Large-scale purification of the enzyme from E. coli cells resulted in a highly active protein which was homogeneous as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and amino terminal sequencing. Antibodies raised against the purified enzyme also reacted with the E. coli EPSPS in Western analyses. The availability of large quantities of the plant enzyme will significantly facilitate mechanistic investigations as well as a comparative study with EPSPS from bacteria and fungi.
Collapse
Affiliation(s)
- S R Padgette
- Plant Molecular Biology, Corporate Research and Development Staff, Chesterfield, Missouri 63198
| | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Shah DM, Tumer NE, Fischhoff DA, Horsch RB, Rogers SG, Fraley RT, Jaworski EG. The Introduction and Expression of Foreign Genes in Plants. Biotechnol Genet Eng Rev 1987. [DOI: 10.1080/02648725.1987.10647835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
45
|
Abstract
The pathway for the degradation of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. PG2982 has been determined by using metabolic radiolabeling experiments. Radiorespirometry experiments utilizing [3-14C]glyphosate revealed that approximately 50 to 59% of the C-3 carbon was oxidized to CO2. Fractionation of stationary-phase cells labeled with [3-14C]glyphosate revealed that from 45 to 47% of the assimilated label is distributed to proteins and that the amino acids methionine and serine are highly labeled. Adenine and guanine received 90% of the C-3 label found in the nucleic acid fraction, and the only pyrimidine base labeled was thymine. These results indicated that C-3 of glyphosate was at some point metabolized to a C-1 compound whose ultimate fate could be both oxidation to CO2 and distribution to amino acids and nucleic acid bases that receive a C-1 group from the C-1-donating coenzyme tetrahydrofolate. Pulse-labeling of PG2982 cells with [3-14C]glyphosate resulted in the isolation of [3-14C]sarcosine as an intermediate in glyphosate degradation. Examination of crude extracts prepared from PG2982 cells revealed the presence of a sarcosine-oxidizing enzyme that oxidizes sarcosine to glycine and formaldehyde. These results indicate that the first step in glyphosate degradation by PG2982 is cleavage of the carbon-phosphorus bond, resulting in the release of sarcosine and a phosphate group. The phosphate group is utilized as a source of phosphorus, and the sarcosine is degraded to glycine and formaldehyde. This pathway is supported by the results of [1,2-14C]glyphosate metabolism studies, which show that radioactivity in the proteins of labeled cells is found only in the glycine and serine residues.
Collapse
|
46
|
Mousdale DM, Coggins JR. Rapid chromatographic purification of glyphosate-sensitive 5-enolpyruvylshikimate 3-phosphate synthase from higher plant chloroplasts. J Chromatogr A 1986; 367:217-22. [PMID: 3782336 DOI: 10.1016/s0021-9673(00)94835-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
47
|
Smith CM, Pratt D, Thompson GA. Increased 5-enolpyruvylshikimic acid 3-phosphate synthase activity in a glyphosate-tolerant variant strain of tomato cells. PLANT CELL REPORTS 1986; 5:298-301. [PMID: 24248252 DOI: 10.1007/bf00269827] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/1985] [Revised: 05/12/1986] [Indexed: 06/02/2023]
Abstract
A glyphosate-tolerant variant of cultured tomato cells (Lycopersicon esculentum × L. peruvianum hybrid) was isolated via a single-step selection. Growth of the variant in suspension culture was essentially unaffected by 10 mM glyphosate, 100 times the concentration needed to significantly reduce the growth rate of wild type cells. When treated with glyphosate, variant cells accumulated much less shikimic acid than did the wild type cells. In analyses of 5-enolpyruvyl-shikimic acid 3-phosphate (EPSP) synthase activity in two separate experiments, the variant cells had 8 and 13 times higher specific activity than the wild type cells. The enzyme activities from the two types of cells were equally inhibited by glyphosate. These results suggest that the glyphosate tolerance of the variant results from overaccumulation of a glyphosate-sensitive EPSP synthase. Attempts to regenerate fertile plants from the variant cells were unsuccessful, but abnormal shoots were regenerated and callus from leaves of these shoots retained the tolerance to glyphosate.
Collapse
Affiliation(s)
- C M Smith
- Department of Bacteriology, University of California-Davis, 95616, Davis, CA, USA
| | | | | |
Collapse
|
48
|
Duncan K, Coggins JR. The serC-aro A operon of Escherichia coli. A mixed function operon encoding enzymes from two different amino acid biosynthetic pathways. Biochem J 1986; 234:49-57. [PMID: 3518706 PMCID: PMC1146525 DOI: 10.1042/bj2340049] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Sub-cloning experiments aimed at precisely locating the E. coli aroA gene, which encodes the shikimate pathway enzyme 5-enolpyruvylshikimate 3-phosphate synthase, showed that in certain constructions, which remain capable of complementing an auxotrophic aroA mutation, expression of aroA is reduced. DNA sequence analysis revealed that a sequence approx. 1200 base pairs (bp) upstream of aroA is necessary for its expression. An open reading frame was identified in this region which encodes a protein of 362 amino acids with a calculated Mr of 39,834 and which ends 70 bp before the start of the aroA coding sequence. This gene has been identified as serC, the structural gene for 3-phosphoserine aminotransferase, an enzyme of the serine biosynthetic pathway. Both genes are expressed as a polycistronic message which is transcribed from a promotor located 58 bp upstream of serC. Evidence is presented which confirms that the aroA and serC genes constitute an operon which has the novel feature of encoding enzymes from two different amino acid biosynthetic pathways.
Collapse
|
49
|
Steinrücken HC, Schulz A, Amrhein N, Porter CA, Fraley RT. Overproduction of 5-enolpyruvylshikimate-3-phosphate synthase in a glyphosate-tolerant Petunia hybrida cell line. Arch Biochem Biophys 1986; 244:169-78. [PMID: 3947056 DOI: 10.1016/0003-9861(86)90106-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Analysis of a Petunia hybrida cell culture (MP4-G) resistant to 1 mM glyphosate revealed a 15- to 20-fold increased level of 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase in the herbicide-tolerant strain. Immunoblotting and enzyme kinetic measurements established that the increased EPSP synthase activity resulted from overproduction of a herbicide-sensitive form of the enzyme. Homogeneous enzyme preparations were obtained from the herbicide-tolerant cell line by sequential ion-exchange, hydroxyapatite, hydrophobic-interaction, and molecular sieve chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and molecular sieve chromatography established the Petunia enzyme to be a monomeric protein with Mr 49,000-55,800. Km values for phosphoenolpyruvate and shikimate 3-phosphate were about 14 and 18 microM, respectively. Glyphosate inhibited the enzyme competitively with phosphoenolpyruvate (Ki = 0.17 microM). These experiments provide further evidence that EPSP synthase is a major site of glyphosate action in plant cells.
Collapse
|
50
|
Smart CC, Johänning D, Müller G, Amrhein N. Selective overproduction of 5-enol-pyruvylshikimic acid 3-phosphate synthase in a plant cell culture which tolerates high doses of the herbicide glyphosate. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)36242-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|