The Dual Role of the 2′-OH Group of A76 tRNATyr in the Prevention of D-tyrosine Mistranslation

Mariia Yu Rybak, Oksana P. Kovalenko, Michael A. Tukalo

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Aminoacyl-tRNA-synthetases are crucial enzymes for initiation step of translation. Possessing editing activity, they protect living cells from misincorporation of non-cognate and non-proteinogenic amino acids into proteins. Tyrosyl-tRNA synthetase (TyrRS) does not have such editing properties, but it shares weak stereospecificity in recognition of D-/L-tyrosine (Tyr). Nevertheless, an additional enzyme, D-aminoacyl-tRNA-deacylase (DTD), exists to overcome these deficiencies. The precise catalytic role of hydroxyl groups of the tRNATyr A76 in the catalysis by TyrRS and DTD remained unknown. To address this issue, [32P]-labeled tRNATyr substrates have been tested in aminoacylation and deacylation assays. TyrRS demonstrates similar activity in charging the 2′ and 3′-OH groups of A76 with L-Tyr. This synthetase can effectively use both OH groups as primary sites for aminoacylation with L-Tyr, but demonstrates severe preference toward 2′-OH, in charging with D-Tyr. In both cases, the catalysis is not substrate-assisted: neither the 2′-OH nor the 3′-OH group assists catalysis. In contrast, DTD catalyzes deacylation of D-Tyr-tRNATyr specifically from the 3′-OH group, while the 2′-OH assists in this hydrolysis.

Original languageEnglish (US)
Pages (from-to)2670-2676
Number of pages7
JournalJournal of Molecular Biology
Issue number17
StatePublished - Aug 17 2018
Externally publishedYes


  • D-Tyr
  • D-aminoacyl-tRNA-deacylase
  • aminoacyl-tRNA synthetase
  • mistranslation
  • tRNA

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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