Unique protein architecture of alanyl-tRNA synthetase for aminoacylation, editing, and dimerization

Masahiro Naganuma, Shun Ichi Sekine, Ryuya Fukunaga, Shigeyuki Yokoyama

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Alanyl-tRNA synthetase (AlaRS) specifically recognizes the major identity determinant, the G3:U70 base pair, in the acceptor stem of tRNAAla by both the tRNA-recognition and editing domains. In this study, we solved the crystal structures of 2 halves of Archaeoglobus fulgidus AlaRS: AlaRS-ΔC, comprising the aminoacylation, tRNA-recognition, and editing domains, and AlaRS-C, comprising the dimerization domain. The aminoacylation/tRNA-recognition domains contain an insertion incompatible with the class-specific tRNA-binding mode. The editing domain is fixed tightly via hydrophobic interactions to the aminoacylation/tRNA-recognition domains, on the side opposite from that in threonyl-tRNA synthetase. A groove formed between the aminoacylation/tRNA- recognition domains and the editing domain appears to be an alternative tRNA-binding site, which might be used for the aminoacylation and/or editing reactions. Actually, the amino acid residues required for the G3:U70 recognition are mapped in this groove. The dimerization domain consists of helical and globular subdomains. The helical subdomain mediates dimerization by forming a helix-loop-helix zipper. The globular subdomain, which is important for the aminoacylation and editing activities, has a positively-charged face suitable for tRNA binding.

Original languageEnglish (US)
Pages (from-to)8489-8494
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number21
StatePublished - May 26 2009
Externally publishedYes


  • Aminoacyl-tRNA synthetase
  • Crystal structure
  • Dimerization domain
  • Proofreading
  • Wobble base pair

ASJC Scopus subject areas

  • General


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