Glu-tRNAGln amidotransferase: a novel heterotrimeric enzyme required for correct decoding of glutamine codons during translation

Proc Natl Acad Sci U S A. 1997 Oct 28;94(22):11819-26. doi: 10.1073/pnas.94.22.11819.


The three genes, gatC, gatA, and gatB, which constitute the transcriptional unit of the Bacillus subtilis glutamyl-tRNAGln amidotransferase have been cloned. Expression of this transcriptional unit results in the production of a heterotrimeric protein that has been purified to homogeneity. The enzyme furnishes a means for formation of correctly charged Gln-tRNAGln through the transamidation of misacylated Glu-tRNAGln, functionally replacing the lack of glutaminyl-tRNA synthetase activity in Gram-positive eubacteria, cyanobacteria, Archaea, and organelles. Disruption of this operon is lethal. This demonstrates that transamidation is the only pathway to Gln-tRNAGln in B. subtilis and that glutamyl-tRNAGln amidotransferase is a novel and essential component of the translational apparatus.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acylation
  • Amino Acid Sequence
  • Bacillus subtilis / enzymology
  • Bacillus subtilis / genetics*
  • Base Sequence
  • Codon
  • Escherichia coli / genetics
  • Glutamine / genetics*
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Nitrogenous Group Transferases / genetics*
  • Nitrogenous Group Transferases / isolation & purification
  • Nitrogenous Group Transferases / metabolism
  • Protein Biosynthesis*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / isolation & purification
  • Sequence Homology, Amino Acid
  • Substrate Specificity


  • Codon
  • Recombinant Proteins
  • Glutamine
  • Nitrogenous Group Transferases
  • glutamyl-tRNA(Gln) amidotransferase

Associated data

  • GENBANK/AF008553