title: Characterization and plant expression of a glyphosate-tolerant enolpyruvylshikimate phosphate synthase.
abstract: BACKGROUND
  Glyphosate tolerance is a dominant trait in modern biotech crops.
  
  
  RESULTS
  A gene encoding a glyphosate-tolerant EPSP synthase (aroA(1398)) from bacterial strain ATX1398 was cloned and characterized. The protein is initiated at a GTG translational start codon to produce a protein that provides robust glyphosate resistance in Escherichia coli (Mig) Cast & Chalm. The aroA(1398) protein was expressed and purified from E. coli, and key kinetic values were determined (K(i) = 161 microM; K(m)(PEP) = 11.3 microM; k(cat) = 28.3 s(-1)). The full-length enzyme is 800-fold more resistant to glyphosate than the maize EPSP synthase while retaining high affinity for the substrate phosphoenol pyruvate. To evaluate further the potential of aroA(1398), transgenic maize events expressing the aroA(1398) protein were generated. T(0) plants were screened for tolerance to glyphosate sprays at 1.3x commercial spray rates, and T(1) plants were selected that completely resisted glyphosate sprays at 1x, 2x and 4x recommended spray rates in field trials.
  
  
  CONCLUSIONS
  These data suggest that aroA(1398) is a suitable candidate for conferring glyphosate tolerance in transgenic crop plants.
authors.affiliation: Athenix Corp., 108 TW Alexander Drive, Research Triangle Park, NC 27709, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Vande Berg
authors.forename: Philip E
authors.initials: PE
authors.lastname: Hammer
authors.forename: Betty L
authors.initials: BL
authors.lastname: Chun
authors.forename: Laura C
authors.initials: LC
authors.lastname: Schouten
authors.forename: Brian
authors.initials: B
authors.lastname: Carr
authors.forename: Rong
authors.initials: R
authors.lastname: Guo
authors.forename: Cheryl
authors.initials: C
authors.lastname: Peters
authors.forename: Todd K
authors.initials: TK
authors.lastname: Hinson
authors.forename: Vadim
authors.initials: V
authors.lastname: Beilinson
authors.forename: Amy
authors.initials: A
authors.lastname: Shekita
authors.forename: Rebekah
authors.initials: R
authors.lastname: Deter
authors.forename: Zhixian
authors.initials: Z
authors.lastname: Chen
authors.forename: Vladimir
authors.initials: V
authors.lastname: Samoylov
authors.forename: Charles T
authors.initials: CT
authors.lastname: Bryant
authors.forename: Maria E
authors.initials: ME
authors.lastname: Stauffer
authors.forename: Timothy
authors.initials: T
authors.lastname: Eberle
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Moellenbeck
authors.forename: Nadine B
authors.initials: NB
authors.lastname: Carozzi
authors.forename: Mike G
authors.initials: MG
authors.lastname: Koziel
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: Duck
mesh_terms: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005998:Glycine / Q000031:analogs & derivatives*; D053209:Herbicide Resistance / Q000235:genetics; D006540:Herbicides; D007700:Kinetics; D030821:Plants, Genetically Modified / Q000201:enzymology*; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics; D000097797:Glyphosate
chemical_list: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate