The influence of 5' codon context on translation termination in Saccharomyces cerevisiae

Eur J Biochem. 1998 Oct 1;257(1):249-54. doi: 10.1046/j.1432-1327.1998.2570249.x.

Abstract

Translation termination in vivo was studied in the yeast Saccharomyces cerevisiae using a translation-assay system. Codon changes that were made at position -2 relative to the stop codon, gave a 3.5-fold effect on termination in a release-factor-defective (sup45) mutant strain, in line with the effect observed in a wild-type strain. The influence of the -2 codon could be correlated to the charge of the corresponding amino acid residue in the nascent peptide; an acidic residue favoring efficient termination. Thus, the C-terminal end of the nascent peptide influences translation termination both in the bacterium Escherichia coli and to a lesser extent in the yeast S. cerevisiae. However, the sensitivity to the charge of the penultimate amino acid is reversed when the E. coli and S. cerevisiae are compared. Changing - 1 (P-site) codons in yeast gave a 10-fold difference in effect on the efficiency of termination. This effect could not be related to any property of the encoded last amino acid in the nascent peptide. Iso-codons read by the same tRNA (AAA/G, GAA/G) gave similar readthrough values. Codons for glutamine (CAA/G), glutamic acid (GAA/G) and isoleucine (AUA/C) that are read by different isoaccepting tRNAs are associated with an approximately twofold difference in each case in termination efficiency. This suggests that the P-site tRNA is able to influence termination at UGAC in yeast.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Codon, Terminator*
  • Escherichia coli / genetics
  • Protein Biosynthesis*
  • RNA, Fungal / genetics
  • RNA, Transfer / genetics
  • Saccharomyces cerevisiae / genetics*
  • Staphylococcal Protein A / genetics

Substances

  • Codon, Terminator
  • RNA, Fungal
  • Staphylococcal Protein A
  • RNA, Transfer