Retracing the evolution of amino acid specificity in glutaminyl-tRNA synthetase

Kwang Won Hong, Michael Ibba, Dieter Söll

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Molecular phylogenetic studies of glutaminyl-tRNA synthetase suggest that it has relatively recently evolved from the closely related enzyme glutamyl-tRNA synthetase. We have now attempted to retrace one of the key steps in this process by selecting glutaminyl-tRNA synthetase mutants displaying enhanced glutamic acid recognition. Mutagenesis of two residues proximal to the active site, Phe-90 and Tyr-240, was found to improve glutamic acid recognition 3-5-fold in vitro and resulted in the misacylation of tRNA(Gln) with glutamic acid. In vivo expression of the genes encoding these misacylating variants of glutaminyl-tRNA synthetase reduced cellular growth rates by 40%, probably as a result of an increase in translational error rates. These results provide the first biochemical evidence that glutaminyl-tRNA synthetase originated through duplication and consequent diversification of an ancestral glutamyl-tRNA synthetase-encoding gene. Copyright (C) 1998 Federation of European of Biochemical Societies.

Original languageEnglish
Pages (from-to)149-154
Number of pages6
JournalFEBS Letters
Volume434
Issue number1-2
DOIs
StatePublished - 28 Aug 1998

Keywords

  • Escherichia coli
  • Evolution
  • Glutamic acid
  • Glutamine
  • Glutaminyl-tRNA synthetase
  • tRNA

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