2qfs
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E.coli EPSP synthase Pro101Ser liganded with S3P
OverviewOverview
Glyphosate, the world's most-used herbicide, is a massive success because, it enables efficient weed control with minimal animal and environmental, toxicity. The molecular target of glyphosate is, 5-enolpyruvylshikimate-3-phosphate synthase (EPSP synthase, or EPSPS), which catalyzes the sixth step of the shikimate pathway in plants and, microorganisms. Glyphosate-tolerant variants of EPSPS constitute the basis, of genetically engineered herbicide-tolerant crops. A single-site mutation, of Pro101 in EPSPS (numbering according to the enzyme from E. coli) has, been implicated in glyphosate-resistant weeds, but this residue is not, directly involved in glyphosate binding, and the basis for this phenomenon, has remained unclear in the absence of further kinetic and structural, characterization. To probe the effects of mutations at this site, E. coli, EPSPS enzymes were produced with glycine, alanine, serine, or leucine, substituted for Pro101. These mutant enzymes were analyzed by steady-state, kinetics, and the crystal structures of the substrate-binary and, substrate*glyphosate-ternary complexes of Pro101Ser and Pro101Leu EPSPS, were determined to between 1.5 and 1.6 angstrom resolution. It appears, that residues smaller than leucine may be substituted for Pro101 without, decreasing catalytic efficiency. Any mutation at this site results in a, structural change of the glyphosate-binding site, shifting residues Thr97, and Gly96 toward the inhibitor molecule. We conclude that the decreased, inhibitory potency observed for glyphosate is a result of these, mutation-induced long-range structural changes. The implications of our, findings concerning the development and spread of glyphosate resistant, weeds are discussed.
About this StructureAbout this Structure
2QFS is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as 3-phosphoshikimate 1-carboxyvinyltransferase, with EC number 2.5.1.19 Full crystallographic information is available from OCA.
ReferenceReference
Structural basis of glyphosate tolerance resulting from mutations of pro101 in E. coli EPSP synthase., Healy-Fried ML, Funke T, Priestman MA, Han H, Schonbrunn E, J Biol Chem. 2007 Sep 12;. PMID:17855366
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