TY - JOUR
T1 - Identification of the residues involved in the unique serine specificity of Caenorhabditis elegans mitochondrial EF-Tu2
AU - Sato, Aya
AU - Watanabe, Yoh Ichi
AU - Suzuki, Tsutomu
AU - Komiyama, Makoto
AU - Watanabe, Kimitsuna
AU - Ohtsuki, Takashi
PY - 2006/9/12
Y1 - 2006/9/12
N2 - 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.
AB - 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.
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U2 - 10.1021/bi060536i
DO - 10.1021/bi060536i
M3 - Article
C2 - 16953577
AN - SCOPUS:33748493391
VL - 45
SP - 10920
EP - 10927
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 36
ER -