Studies on T. Utilis tRNATyr variants with enzymatically altered D-loop sequences. I. deletion of the conserved sequence Gm-G and its effects on aminoacylation and conformation

Takashi Ohyama, Kazuya Nishikawa, Shosuke Takemura

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Variants of T. utilis tRNATyr containing deletions or substitutions of nucleotides in the D-loop region have been prepared by several enzymatic reaction steps in vitro. Although these variants lack the "conserved" nucleotides Gm18-G19 in their D-loop, their tyrosine-accepting capacities are indistinguishable from that of the native tRNATyr. Thermal denaturation studies with tRNATyr variants lacking the Gm18-G19 sequence have revealed a biphasic nature of the melting profile, suggesting the loss of tertiary interactions between Gm18-G19 and somewhere in the molecule (probably in the TψC-loop region). These results indicate that nucleotide sequences around Gm18-G19(i.e. D16-D-Gm-G19 or Gm18-G-D-D21) themselves are not essential sites for the recognition of tRNATyr by T. utilis tyrosyl-tRNA synthetase and that tRNATyr variants with an apparently "relaxed" conformation still have full aminoacylation capacities at around 30°C.

Original languageEnglish
Pages (from-to)29-36
Number of pages8
JournalJournal of Biochemistry
Issue number1
Publication statusPublished - 1985 Jan
Externally publishedYes


ASJC Scopus subject areas

  • Statistics, Probability and Uncertainty
  • Applied Mathematics
  • Physiology (medical)
  • Radiology Nuclear Medicine and imaging
  • Molecular Biology
  • Biochemistry

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