A single amino acid substitution in the enzyme 5-enolpyruvylshikimate-3-phosphate synthase confers resistance to the herbicide glyphosate.
The enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EC 2.5.1.19), encoded by the aroA locus, is a target site of glyphosate inhibition in bacteria. A glyphosate-resistant aroA allele has been cloned in Escherichia coli from a mutagenized strain of Salmonella typhimurium. Subcloning of this mutant aroA allele shows the gene to reside on a 1.3-kilobase segment of S. typhimurium DNA. Nucleotide sequence analysis of this mutant gene indicates a protein-coding region 427 amino acids in length. Comparison of the mutant and wild type aroA gene sequences reveals a single base pair change resulting in a Pro to Ser amino acid substitution at the 101st codon of the protein. A hybrid gene fusion between mutant and wild type aroA gene sequences was constructed. 5-Enolpyruvylshikimate-3-phosphate synthase was prepared from E. coli cells harboring this construct. The glyphosate-resistant phenotype is shown to be associated with the single amino acid substitution described above.
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D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D019883:Alkyl and Aryl Transferases; D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004351:Drug Resistance; D004926:Escherichia coli; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006540:Herbicides / Q000494:pharmacology*; D012486:Salmonella typhimurium; D013329:Structure-Activity Relationship; D014166:Transferases / Q000235:genetics* / Q000378:metabolism; D000097797:Glyphosate
D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D019883:Alkyl and Aryl Transferases; D004262:DNA Restriction Enzymes; D005998:Glycine; D006540:Herbicides; D014166:Transferases; D000097797:Glyphosate