EPSP synthase

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EPSP Synthase (3-phosphoshikimate 1-carboxyvinyltransferase)
EPSP synthase.PNG
EPSP synthase liganded with shikimate. [1]
Identifiers
EC no. 2.5.1.19
CAS no. 9068-73-9
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO
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PMC articles
PubMed articles
NCBI proteins
EPSP synthase (3-phosphoshikimate 1-carboxyvinyltransferase)
EPSP synthase cartoon.PNG
Ribbon diagram of EPSP synthase
Identifiers
SymbolEPSP_synthase
Pfam PF00275
InterPro IPR001986
PROSITE PDOC00097
SCOP2 1eps / SCOPe / SUPFAM
Available protein structures:
Pfam   structures / ECOD  
PDB RCSB PDB; PDBe; PDBj
PDBsum structure summary

5-enolpyruvylshikimate-3-phosphate (EPSP) synthase is an enzyme produced by plants and microorganisms. EPSPS catalyzes the chemical reaction:

Contents

phosphoenolpyruvate (PEP) + 3-phospho shikimate (S3P) phosphate + 5-enolpyruvylshikimate-3-phosphate (EPSP)

Thus, the two substrates of this enzyme are phosphoenolpyruvate (PEP) and 3-phosphoshikimate, whereas its two products are phosphate and 5-enolpyruvylshikimate-3-phosphate.

This enzyme is not present in the genomes of animals. It presents an attractive biological target for herbicides, such as glyphosate. A glyphosate-resistant version of this gene has been used in genetically modified crops.

Nomenclature

The enzyme belongs to the family of transferases, to be specific those transferring aryl or alkyl groups other than methyl groups. The systematic name of this enzyme class is phosphoenolpyruvate:3-phosphoshikimate 5-O-(1-carboxyvinyl)-transferase. Other names in common use include:

Structure

EPSP synthase is a monomeric enzyme with a molecular mass of about 46,000. [2] [3] [4] It is composed of two domains, which are joined by protein strands. This strand acts as a hinge, and can bring the two protein domains closer together. When a substrate binds to the enzyme, ligand bonding causes the two parts of the enzyme to clamp down around the substrate in the active site.

EPSP synthase has been divided into two groups according to glyphosate sensitivity. Class I enzyme, contained in plants and in some bacteria, is inhibited at low micromolar glyphosate concentrations, whereas class II enzyme, found in other bacteria, is resistant to inhibition by glyphosate. [5]

Shikimate pathway

EPSP synthase participates in the biosynthesis of the aromatic amino acids phenylalanine, tyrosine, and tryptophan via the shikimate pathway in bacteria, fungi, and plants. EPSP synthase is produced only by plants and micro-organisms; the gene coding for it is not in the mammalian genome. [6] [7] Gut flora of some animals contain EPSPS. [8]

Reaction

EPSP synthase catalyzes the reaction which converts shikimate-3-phosphate plus phosphoenolpyruvate to 5-enolpyruvylshikimate-3-phosphate (EPSP) by way of an acetal-like tetrahedral intermediate. [9] [10] Basic and amino acids in the active site are involved in deprotonation of the hydroxyl group of PEP and in the proton-exchange steps related to the tetrahedral intermediate itself, respectively. [11]

EPSPreactionII.svg

Studies of the enzyme kinetics for this reaction have determined the specific sequence and energetics of each step of the process. [12]

Herbicide target

EPSP synthase is the biological target for the herbicide glyphosate. [13] Glyphosate is a competitive inhibitor of EPSP synthase, acting as a transition state analog that binds more tightly to the EPSPS-S3P complex than PEP and inhibits the shikimate pathway. This binding leads to inhibition of the enzyme's catalysis and shuts down the pathway. Eventually this results in organism death from lack of aromatic amino acids the organism requires to survive. [5] [14]

A version of the enzyme that both was resistant to glyphosate and that was still efficient enough to drive adequate plant growth was identified by Monsanto scientists after much trial and error in an Agrobacterium strain called CP4 ( Q9R4E4 ). The strain CP4 was found surviving in a waste-fed column at a glyphosate production facility. The CP4 EPSP synthase enzyme has been engineered into several genetically modified crops. [5] [15]

Related Research Articles

<span class="mw-page-title-main">Herbicide</span> Type of chemical used to kill unwanted plants

Herbicides, also commonly known as weed killers, are substances used to control undesired plants, also known as weeds. Selective herbicides control specific weed species while leaving the desired crop relatively unharmed, while non-selective herbicides (sometimes called total weed killers kill plants indiscriminately. Due to herbicide resistance – a major concern in agriculture – a number of products combine herbicides with different means of action. Integrated pest management may use herbicides alongside other pest control methods.

<span class="mw-page-title-main">Glyphosate</span> Systemic herbicide and crop desiccant

Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSP). It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. Its herbicidal effectiveness was discovered by Monsanto chemist John E. Franz in 1970. Monsanto brought it to market for agricultural use in 1974 under the trade name Roundup. Monsanto's last commercially relevant United States patent expired in 2000.

Shikimic acid, more commonly known as its anionic form shikimate, is a cyclohexene, a cyclitol and a cyclohexanecarboxylic acid. It is an important biochemical metabolite in plants and microorganisms. Its name comes from the Japanese flower shikimi, from which it was first isolated in 1885 by Johan Fredrik Eykman. The elucidation of its structure was made nearly 50 years later.

<span class="mw-page-title-main">Chorismic acid</span> Chemical compound

Chorismic acid, more commonly known as its anionic form chorismate, is an important biochemical intermediate in plants and microorganisms. It is a precursor for:

<span class="mw-page-title-main">Phosphoenolpyruvic acid</span> Chemical compound

Phosphoenolpyruvate is the carboxylic acid derived from the enol of pyruvate and phosphate. It exists as an anion. PEP is an important intermediate in biochemistry. It has the highest-energy phosphate bond found in organisms, and is involved in glycolysis and gluconeogenesis. In plants, it is also involved in the biosynthesis of various aromatic compounds, and in carbon fixation; in bacteria, it is also used as the source of energy for the phosphotransferase system.

<span class="mw-page-title-main">Phosphoenolpyruvate carboxylase</span> Class of enzymes

Phosphoenolpyruvate carboxylase (also known as PEP carboxylase, PEPCase, or PEPC; EC 4.1.1.31, PDB ID: 3ZGE) is an enzyme in the family of carboxy-lyases found in plants and some bacteria that catalyzes the addition of bicarbonate (HCO3) to phosphoenolpyruvate (PEP) to form the four-carbon compound oxaloacetate and inorganic phosphate:

<span class="mw-page-title-main">Aromatic amino acid</span> Amino acid having an aromatic ring

An aromatic amino acid is an amino acid that includes an aromatic ring.

<span class="mw-page-title-main">Erythrose 4-phosphate</span> Chemical compound

Erythrose 4-phosphate is a phosphate of the simple sugar erythrose. It is an intermediate in the pentose phosphate pathway and the Calvin cycle.

<span class="mw-page-title-main">Shikimate dehydrogenase</span> Enzyme involved in amino acid biosynthesis

In enzymology, a shikimate dehydrogenase (EC 1.1.1.25) is an enzyme that catalyzes the chemical reaction

<span class="mw-page-title-main">3-dehydroquinate synthase</span> Enzyme

The enzyme 3-dehydroquinate synthase catalyzes the chemical reaction

<span class="mw-page-title-main">Chorismate synthase</span>

The enzyme chorismate synthase catalyzes the chemical reaction

Roundup Ready is the Monsanto trademark for its patented line of genetically modified crop seeds that are resistant to its glyphosate-based herbicide, Roundup.

<span class="mw-page-title-main">Pyruvate, phosphate dikinase</span>

Pyruvate, phosphate dikinase, or PPDK is an enzyme in the family of transferases that catalyzes the chemical reaction

In enzymology, a pyruvate, water dikinase (EC 2.7.9.2) is an enzyme that catalyzes the chemical reaction

<span class="mw-page-title-main">Shikimate kinase</span>

Shikimate kinase (EC 2.7.1.71) is an enzyme that catalyzes the ATP-dependent phosphorylation of shikimate to form shikimate 3-phosphate. This reaction is the fifth step of the shikimate pathway, which is used by plants and bacteria to synthesize the common precursor of aromatic amino acids and secondary metabolites. The systematic name of this enzyme class is ATP:shikimate 3-phosphotransferase. Other names in common use include shikimate kinase (phosphorylating), and shikimate kinase II.

The Aminoshikimate pathway is a biochemical pathway present in some plants, which has been studied by biologists, biochemists and especially those interested in manufacture of novel antibiotic drugs. The pathway is a novel variation of the shikimate pathway. The aminoshikimate pathway was first discovered and studied in the rifamycin B producer Amycolatopsis mediterranei. Its end product, 3-amino-5-hydroxybenzoate, serves as an initiator for polyketide synthases in the biosynthesis of ansamycins.

<span class="mw-page-title-main">Shikimate pathway</span> Biosynthetic Pathway

The shikimate pathway is a seven-step metabolic pathway used by bacteria, archaea, fungi, algae, some protozoans, and plants for the biosynthesis of folates and aromatic amino acids. This pathway is not found in animal cells.

<span class="mw-page-title-main">DAHP synthase</span> Class of enzymes

3-Deoxy-D-arabinoheptulosonate 7-phosphate (DAHP) synthase is the first enzyme in a series of metabolic reactions known as the shikimate pathway, which is responsible for the biosynthesis of the amino acids phenylalanine, tyrosine, and tryptophan. Since it is the first enzyme in the shikimate pathway, it controls the amount of carbon entering the pathway. Enzyme inhibition is the primary method of regulating the amount of carbon entering the pathway. Forms of this enzyme differ between organisms, but can be considered DAHP synthase based upon the reaction that is catalyzed by this enzyme.

(6<i>S</i>)-6-Fluoroshikimic acid Chemical compound

(6S)-6-Fluoroshikimic acid is an antibacterial agent acting on the aromatic biosynthetic pathway. It may be used against Plasmodium falciparum, the causative agent of malaria. The molecule is targeting the enzymes of the shikimate pathway. This metabolic pathway is not present in mammals. The mechanism of action of the molecule is not through the inhibition of chorismate synthase but by the inhibition of 4-aminobenzoic acid synthesis.

3-Deoxy-<small>D</small>-<i>arabino</i>-heptulosonic acid 7-phosphate Chemical compound

3-Deoxy-D-arabino-heptulosonic acid 7-phosphate (DAHP) is a 7-carbon ulonic acid. This compound is found in the shikimic acid biosynthesis pathway and is an intermediate in the production of aromatic amino acids.

References

  1. Priestman MA, Healy ML, Funke T, Becker A, Schönbrunn E (October 2005). "Molecular basis for the glyphosate-insensitivity of the reaction of 5-enolpyruvylshikimate 3-phosphate synthase with shikimate". FEBS Lett. 579 (25): 5773–80. doi: 10.1016/j.febslet.2005.09.066 . PMID   16225867. S2CID   26614581.
  2. Goldsbrough, Peter (1990). "Gene amplification in glyphosate tolerant tobacco cells". Plant Science. 72 (1): 53–62. doi:10.1016/0168-9452(90)90186-r.
  3. Abdel-Meguid SS, Smith WW, Bild GS (Dec 1985). "Crystallization of 5-enolpyruvylshikimate 3-phosphate synthase from Escherichia coli". Journal of Molecular Biology. 186 (3): 673. doi:10.1016/0022-2836(85)90140-8. PMID   3912512.
  4. Ream JE, Steinrücken HC, Porter CA, Sikorski JA (May 1988). "Purification and Properties of 5-Enolpyruvylshikimate-3-Phosphate Synthase from Dark-Grown Seedlings of Sorghum bicolor". Plant Physiology. 87 (1): 232–8. doi:10.1104/pp.87.1.232. PMC   1054731 . PMID   16666109.
  5. 1 2 3 Pollegioni L, Schonbrunn E, Siehl D (Aug 2011). "Molecular basis of glyphosate resistance-different approaches through protein engineering". The FEBS Journal. 278 (16): 2753–66. doi:10.1111/j.1742-4658.2011.08214.x. PMC   3145815 . PMID   21668647.
  6. Funke T, Han H, Healy-Fried ML, Fischer M, Schönbrunn E (Aug 2006). "Molecular basis for the herbicide resistance of Roundup Ready crops". Proceedings of the National Academy of Sciences of the United States of America. 103 (35): 13010–5. Bibcode:2006PNAS..10313010F. doi: 10.1073/pnas.0603638103 . JSTOR   30050705. PMC   1559744 . PMID   16916934.
  7. Maeda H, Dudareva N (2012). "The shikimate pathway and aromatic amino Acid biosynthesis in plants". Annual Review of Plant Biology. 63 (1): 73–105. doi:10.1146/annurev-arplant-042811-105439. PMID   22554242. The AAA pathways consist of the shikimate pathway (the prechorismate pathway) and individual postchorismate pathways leading to Trp, Phe, and Tyr.... These pathways are found in bacteria, fungi, plants, and some protists but are absent in animals. Therefore, AAAs and some of their derivatives (vitamins) are essential nutrients in the human diet, although in animals Tyr can be synthesized from Phe by Phe hydroxylase....The absence of the AAA pathways in animals also makes these pathways attractive targets for antimicrobial agents and herbicides.
  8. Cerdeira AL, Duke SO (2006). "The current status and environmental impacts of glyphosate-resistant crops: a review". Journal of Environmental Quality. 35 (5): 1633–58. doi:10.2134/jeq2005.0378. PMID   16899736.
  9. "8.18.4.1.1. EPSP synthase: A tetrahedral ketal phosphate enzyme intermediate". Comprehensive Natural Products II. Chemistry and Biology. Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Vol. 8. 2010. pp. 663–688.
  10. Anderson, Karen S.; Sammons, R. Douglas; Leo, Gregory C.; Sikorski, James A.; Benesi, Alan J.; Johnson, Kenneth A. (1990). "Observation by carbon-13 NMR of the EPSP synthase tetrahedral intermediate bound to the enzyme active site". Biochemistry. 29 (6): 1460–1465. doi:10.1021/bi00458a017. PMID   2334707.
  11. Park, HaJeung; Hilsenbeck, Jacqueline L.; Kim, Hak Jun; Shuttleworth, Wendy A.; Park, Yong Ho; Evans, Jeremy N.; Kang, ChulHee (2004). "Structural studies of Streptococcus pneumoniae EPSP synthase in unliganded state, tetrahedral intermediate‐bound state and S3P‐GLP‐bound state". Molecular Microbiology. 51 (4): 963–971. doi: 10.1046/j.1365-2958.2003.03885.x . PMID   14763973. S2CID   45549442.
  12. Anderson, Karen S.; Sikorski, James A.; Johnson, Kenneth A. (1988). "A tetrahedral intermediate in the EPSP synthase reaction observed by rapid quench kinetics". Biochemistry. 27 (19): 7395–7406. doi:10.1021/bi00419a034. PMID   3061457.
  13. Fonseca, Emily C. M.; da Costa, Kauê S.; Lameira, Jerônimo; Alves, Cláudio Nahum; Lima, Anderson H. (2020). "Investigation of the target-site resistance of EPSP synthase mutants P106T and T102I/P106S against glyphosate". RSC Advances. 10 (72): 44352–44360. doi: 10.1039/D0RA09061A . ISSN   2046-2069. PMC   9058485 .
  14. Schönbrunn E, Eschenburg S, Shuttleworth WA, Schloss JV, Amrhein N, Evans JN, Kabsch W (Feb 2001). "Interaction of the herbicide glyphosate with its target enzyme 5-enolpyruvylshikimate 3-phosphate synthase in atomic detail". Proceedings of the National Academy of Sciences of the United States of America. 98 (4): 1376–80. Bibcode:2001PNAS...98.1376S. doi: 10.1073/pnas.98.4.1376 . PMC   29264 . PMID   11171958.
  15. Green JM, Owen MD (Jun 2011). "Herbicide-resistant crops: utilities and limitations for herbicide-resistant weed management". Journal of Agricultural and Food Chemistry. 59 (11): 5819–29. doi:10.1021/jf101286h. PMC   3105486 . PMID   20586458.

Further reading