In vitro mutagenesis of the mitochondrial leucyl-tRNA synthetase ofS. cerevisiaereveals residues critical for its in vivo activities

✍ Scribed by Guo-ya Li; Christopher J. Herbert; Michel Labouesse; Piotr P. Slonimski

• Publisher: Springer-Verlag
• Year: 1992
• Tongue: English
• Weight: 684 KB
• Volume: 22
• Category: Article
• ISSN: 0172-8083
• DOI: 10.1007/bf00351744

✦ Synopsis

The mitochondrial leucyl-tRNA synthetase (mLRS) of Saccharomyces cerevisiae is involved in both mitochondrial protein synthesis and pre-mRNA splicing. We have created mutations in the regions HIGH, GWD and KMSKS, which are involved in ATP-, amino acid- and tRNA-binding respectively, and which have been conserved in the evolution of group I tRNA synthetases. The mutants GRD and NMSKS have no discernible phenotype. The mutants AWD and ARD act as null alleles and lead to the production of 100% cytoplasmic petites. The mutants HIGN, NIGH and KMSNS are unable to grow on glycerol even in the presence of an intronless mitochondrial genome and accumulate petites to a greater extent than the wild-type but less than 40%. Experiments with an imported bI4 maturase indicate that the lesion in these mutations primarily affects the synthetase and not the splicing functions.