The ATP-mediated formation of the YgjD-YeaZ-YjeE complex is required for the biosynthesis of tRNA t6A in Escherichia coli

Nucleic Acids Res. 2015 Feb 18;43(3):1804-17. doi: 10.1093/nar/gku1397. Epub 2015 Jan 10.


The essential and universal N(6)-threonylcarbamoyladenosine (t(6)A) modification at position 37 of ANN-decoding tRNAs plays a pivotal role in translational fidelity through enhancement of the cognate codon recognition and stabilization of the codon-anticodon interaction. In Escherichia coli, the YgjD (TsaD), YeaZ (TsaB), YjeE (TsaE) and YrdC (TsaC) proteins are necessary and sufficient for the in vitro biosynthesis of t(6)A, using tRNA, ATP, L-threonine and bicarbonate as substrates. YrdC synthesizes the short-lived L-threonylcarbamoyladenylate (TCA), and YgjD, YeaZ and YjeE cooperate to transfer the L-threonylcarbamoyl-moiety from TCA onto adenosine at position 37 of substrate tRNA. We determined the crystal structure of the heterodimer YgjD-YeaZ at 2.3 Å, revealing the presence of an unexpected molecule of ADP bound at an atypical site situated at the YgjD-YeaZ interface. We further showed that the ATPase activity of YjeE is strongly activated by the YgjD-YeaZ heterodimer. We established by binding experiments and SAXS data analysis that YgjD-YeaZ and YjeE form a compact ternary complex only in presence of ATP. The formation of the ternary YgjD-YeaZ-YjeE complex is required for the in vitro biosynthesis of t(6)A but not its ATPase activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / metabolism
  • Adenosine Triphosphate / metabolism
  • Adenosine Triphosphate / physiology*
  • Binding Sites
  • Dimerization
  • Electrophoresis, Agar Gel
  • Escherichia coli / genetics*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism*
  • Models, Molecular
  • Protein Conformation
  • RNA, Bacterial / biosynthesis*
  • RNA, Bacterial / metabolism
  • RNA, Transfer / biosynthesis*


  • Escherichia coli Proteins
  • RNA, Bacterial
  • YeaZ protein, E coli
  • YgjD protein, E coli
  • YjeE protein, E coli
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • RNA, Transfer