Crystal structure of tRNA adenosine deaminase (TadA) from Aquifex aeolicus

Mitsuo Kuratani, Ryohei Ishii, Yoshitaka Bessho, Ryuya Fukunaga, Toru Sengoku, Mikako Shirouzu, Shun Ichi Sekine, Shigeyuki Yokoyama

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


The bacterial tRNA adenosine deaminase (TadA) generates inosine by deaminating the adenosine residue at the wobble position of tRNA Arg-2. This modification is essential for the decoding system. In this study, we determined the crystal structure of Aquifex aeolicus TadA at a 1.8-Å resolution. This is the first structure of a deaminase acting on tRNA. A. aeolicus TadA has an α/β/α three-layered fold and forms a homodimer. The A. aeolicus TadA dimeric structure is completely different from the tetrameric structure of yeast CDD1, which deaminates mRNA and cytidine, but is similar to the dimeric structure of yeast cytosine deaminase. However, in the A. aeolicus TadA structure, the shapes of the C-terminal helix and the regions between the β4 and β5 strands are quite distinct from those of yeast cytosine deaminase and a large cavity is produced. This cavity contains many conserved amino acid residues that are likely to be involved in either catalysis or tRNA binding. We made a docking model of TadA with the tRNA anticodon stem loop.

Original languageEnglish (US)
Pages (from-to)16002-16008
Number of pages7
JournalJournal of Biological Chemistry
Issue number16
StatePublished - Apr 22 2005
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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