1MI4

Glyphosate insensitive G96A mutant EPSP synthase liganded with shikimate-3-phosphate

Summary for 1MI4

• Entry DOI: 10.2210/pdb1mi4/pdb
• Related: 1G6S 1G6T
• Descriptor: 5-enolpyruvylshikimate-3-phosphate synthase, SHIKIMATE-3-PHOSPHATE, FORMIC ACID, ... (4 entities in total)
• Functional Keywords: inside-out alpha-beta barrel, transferase
• Biological source: Escherichia coli
• Cellular location: Cytoplasm : P0A6D3
• Total number of polymer chains: 1
• Total formula weight: 47054.12

Authors

Eschenburg, S.,Healy, M.L.,Priestman, M.A.,Lushington, G.H.,Schonbrunn, E. (deposition date: 2002-08-21, release date: 2002-12-18, Last modification date: 2023-10-25)

Primary citation

Eschenburg, S.,Healy, M.L.,Priestman, M.A.,Lushington, G.H.,Schonbrunn, E.
How the mutation glycine96 to alanine confers glyphosate insensitivity to 5-enolpyruvyl shikimate-3-phosphate synthase from Escherichia coli.
PLANTA, 216:129-135, 2002

PubMed Abstract: The enzyme 5-enolpyruvyl shikimate-3-phosphate (EPSP) synthase (EC 2.5.1.19) is essential for the biosynthesis of aromatic compounds in plants and microbes and is the unique target of the herbicide glyphosate. One of the first glyphosate-insensitive enzymes reported was a Gly96Ala mutant of EPSP synthase from Klebsiella pneumoniae. We have introduced this single-site mutation into the highly homologous EPSP synthase from Escherichia coli. The mutant enzyme is insensitive to glyphosate with unaltered affinity for its first substrate, shikimate-3-phosphate (S3P), but displays a 30-fold lower affinity for its second substrate, phosphoenolpyruvate (PEP). Using X-ray crystallography, we solved the structure of Gly96Ala-EPSP synthase liganded with S3P to 0.17 nm resolution. The crystal structure shows that the additional methyl group from Ala96 protrudes into the active site of the enzyme. While the interactions between enzyme and S3P remain unaffected, the accessible volume for glyphosate binding is substantially reduced. Exploiting the crystallographic results for molecular modeling, we demonstrate that PEP but not glyphosate can be docked in the Gly96Ala-modified binding site. The predicted PEP binding site satisfies the earlier proposed interaction pattern for PEP with EPSP synthase and corroborates the assumption that glyphosate and PEP target the same binding site.

PubMed: 12430021
DOI: 10.1007/s00425-002-0908-0

Experimental method

X-RAY DIFFRACTION (1.7 Å)