Identification of the residues involved in the unique serine specificity of Caenorhabditis elegans mitochondrial EF-Tu2

Aya Sato, Yoh Ichi Watanabe, Tsutomu Suzuki, Makoto Komiyama, Kimitsuna Watanabe, Takashi Ohtsuki

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

In canonical translation systems, the single elongation factor Tu (EF-Tu) recognizes all elongator tRNAs. However, in Caenorhabditis elegans mitochondria, two distinct EF-Tu species, EF-Tul and EF-Tu2, recognize 20 species of T armless tRNA and two species of D armless tRNASer, respectively. We previously reported that C. elegans mitochondrial EF-Tu2 specifically recognizes the serine moiety of serylated-tRNA. In this study, to identify the critical residues for the serine specificity in EF-Tu2, several residues in the amino acid binding pocket of bacterial EF-Tu were systematically replaced with corresponding EF-Tu2 residues, and the mutants were analyzed for their specificity for esterified amino acids attached to tRNAs. In this way, we obtained a bacterial EF-Tu mutant that acquired serine specificity after the introduction of 10 EF-Tu2 residues into its amino acid binding pocket. C. elegans EF-Tu2 mutants lacking serine specificity were also created by replacing seven or eight residues with bacterial residues. Further stressing the importance of these residues, we found that they are almost conserved in EF-Tu2 sequences of closely related nematodes. Thus, these three approaches reveal the critical residues essential for the unique serine specificity of C. elegans mitochondrial EF-Tu2.

Original languageEnglish
Pages (from-to)10920-10927
Number of pages8
JournalBiochemistry
Volume45
Issue number36
DOIs
Publication statusPublished - Sep 12 2006

ASJC Scopus subject areas

  • Biochemistry

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