A minimalist glutamyl-tRNA synthetase dedicated to aminoacylation of the tRNAAsp QUC anticodon

Nucleic Acids Res. 2004 May 18;32(9):2768-75. doi: 10.1093/nar/gkh608. Print 2004.


Escherichia coli encodes YadB, a protein displaying 34% identity with the catalytic core of glutamyl-tRNA synthetase but lacking the anticodon-binding domain. We show that YadB is a tRNA modifying enzyme that evidently glutamylates the queuosine residue, a modified nucleoside at the wobble position of the tRNA(Asp) QUC anticodon. This conclusion is supported by a variety of biochemical data and by the inability of the enzyme to glutamylate tRNA(Asp) isolated from an E.coli tRNA-guanosine transglycosylase minus strain deprived of the capacity to exchange guanosine 34 with queuosine. Structural mimicry between the tRNA(Asp) anticodon stem and the tRNA(Glu) amino acid acceptor stem in prokaryotes encoding YadB proteins indicates that the function of these tRNA modifying enzymes, which we rename glutamyl-Q tRNA(Asp) synthetases, is conserved among prokaryotes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acylation
  • Anticodon / chemistry
  • Anticodon / genetics
  • Anticodon / metabolism*
  • Base Sequence
  • Biological Evolution
  • Conserved Sequence
  • Escherichia coli / enzymology*
  • Escherichia coli / genetics*
  • Glutamate-tRNA Ligase / chemistry*
  • Glutamate-tRNA Ligase / genetics
  • Glutamate-tRNA Ligase / metabolism*
  • Molecular Mimicry
  • Nucleoside Q / genetics
  • Nucleoside Q / metabolism*
  • Periodic Acid / pharmacology
  • RNA, Bacterial / chemistry
  • RNA, Bacterial / genetics
  • RNA, Bacterial / metabolism
  • RNA, Transfer, Asp / chemistry
  • RNA, Transfer, Asp / genetics
  • RNA, Transfer, Asp / metabolism*
  • RNA, Transfer, Glu / chemistry
  • RNA, Transfer, Glu / genetics
  • RNA, Transfer, Glu / metabolism


  • Anticodon
  • RNA, Bacterial
  • RNA, Transfer, Asp
  • RNA, Transfer, Glu
  • Periodic Acid
  • Nucleoside Q
  • metaperiodate
  • Glutamate-tRNA Ligase