A viable amino acid editing activity in the leucyl-tRNA synthetase CP1-splicing domain is not required in the yeast mitochondria

Vrajesh A. Karkhanis, Michal T. Boniecki, Kiranmai Poruri, Susan A. Martinis

Research output: Contribution to journalArticlepeer-review

Abstract

Aminoacyl-tRNA synthetases are a family of enzymes that are responsible for translating the genetic code in the first step of protein synthesis. Some aminoacyl-tRNA synthetases have editing activities to clear their mistakes and enhance fidelity. Leucyl-tRNA synthetases have a hydrolytic active site that resides in a discrete amino acid editing domain called CP1. Mutational analysis within yeast mitochondrial leucyl-tRNA synthetase showed that the enzyme has maintained an editing active site that is competent for post-transfer editing of mischarged tRNA similar to other leucyl-tRNA synthetases. These mutations that altered or abolished leucyl-tRNA synthetase editing were introduced into complementation assays. Cell viability and mitochondrial function were largely unaffected in the presence of high levels of non-leucine amino acids. In contrast, these editing-defective mutations limited cell viability in Escherichia coli. It is possible that the yeast mitochondria have evolved to tolerate lower levels of fidelity in protein synthesis or have developed alternate mechanisms to enhance discrimination of leucine from non-cognate amino acids that can be misactivated by leucyl-tRNA synthetase.

Original languageEnglish (US)
Pages (from-to)33217-33225
Number of pages9
JournalJournal of Biological Chemistry
Volume281
Issue number44
DOIs
StatePublished - Nov 3 2006

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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