Two kinetically distinct tRNAile isoacceptors in Escherichia coli C6.
AUTOR(ES)
Harris, C L
RESUMO
The isoleucine acceptance of tRNA from Escherichia coli C6 was previously shown to be influenced by the synthetase level (Marashi, F. and Harris, C.L. 1977. Biochim. Biophys. Acta 477, 84-88). We show here that the increased acceptance observed at higher enzyme levels is accompanied by an increase in the aminoacylation of one tRNAile species. Hence, tRNAile, a minor species at low enzyme levels, is a major isoacceptor after full aminoacylation. The two major isoleucine species have been purified using a combination of BD-cellulose, DEAE-Sephadex A-50 and methylated albumin kieselguhr chromatography. tRNAile (1511 pmoles ile/A260 of tRNA) was found to be slowly acylated, with 2a Vmax one-seventh that observed with tRNAil3le (1475 pmoles ile/A260). Two-dimensional TLC analysis of RNase T2 digests revealed differences in nucleotide content between the purified tRNAs. These results are discussed in terms of the presence of slow and fast tRNAile species in E. coli.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=324055Documentos Relacionados
- Structure of the Saccharomyces cerevisiae gene encoding tRNAIle (IAU).
- A pathogenic point mutation reduces stability of mitochondrial mutant tRNAIle
- Yeast mitochondrial tRNAIle and tRNAMetm: nucleotide sequence and codon recognition patterns.
- Pathology-related substitutions in human mitochondrial tRNAIle reduce precursor 3′ end processing efficiency in vitro
- Direct experimental evidence for kinetic proofreading in amino acylation of tRNAIle.