Specific Substitution into the Anticodon Loop of Yeast Tyrosine Transfer RNA

Lance A. Bare, Olke C. Uhlenbeck

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

The aminoacylation kinetics of 19 different variants of yeast tRNATyr with nucleotide substitutions in positions 33–35 were determined. Substitution of the conserved uridine-33 does not alter the rate of aminoacylation. However, substitution of the anticodon position 34 or position 35 reduces Km from 2-to 10-fold and Kmax as much as 2-fold, depending on the nucleotide inserted. The ochre and amber suppressor tRNAsTyr both showed about a 7-fold reduction in Vmax/Km. Data from tRNATyr with different modified nucleotides at position 35 suggest that specific hydrogen bonds form between the synthetase and both the N1 and N3 hydrogens of Ψ-35. The effect of simultaneous substitutions at positions 34 and 35 can be predicted reasonably well by combining the effects of single substitutions. These data suggest that yeast tyrosyl-tRNA synthetase interacts with positions 34 and 35 of the anticodon of tRNATyr and opens the possibility that nonsense suppressor efficiency may be mediated by the level of aminoacylation.

Original languageEnglish (US)
Pages (from-to)5825-5830
Number of pages6
JournalBiochemistry
Volume25
Issue number19
DOIs
StatePublished - Sep 1986

ASJC Scopus subject areas

  • Biochemistry

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