UGA suppression by a mutant RNA of the large ribosomal subunit
| Autor: | Emanuel J. Murgola, David K. Jemiolo, Frances T. Pagel |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Ribosomal Proteins
Mutant Molecular Sequence Data Restriction Mapping Biology Suppression Genetic 23S ribosomal RNA Ribosomal protein Large ribosomal subunit RNA Ribosomal 16S Operon Escherichia coli Codon Suppressor mutation Genetics Multidisciplinary Base Sequence Ribosomal RNA Peptide Chain Termination Translational Molecular biology Stop codon Models Structural RNA Ribosomal 23S Genes Bacterial Mutagenesis Transfer RNA Nucleic Acid Conformation Plasmids Research Article |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America. 92(26) |
| ISSN: | 0027-8424 |
| Popis: | A role for rRNA in peptide chain termination was indicated several years ago by isolation of a 168 rRNA (small subunit) mutant of Escherichia coli that suppressed UGA mutations. In this paper, we describe another interesting rRNA mutant, selected as a translational suppressor of the chain-terminating mutant trpA (UGA211) of E. coli. The finding that it suppresses UGA at two positions in trpA and does not suppress the other two termination codons, UAA and UAG, at the same codon positions (or several missense mutations, including UGG, available at one of the two positions) suggests a defect in UGA-specific termination. The suppressor mutation was mapped by plasmid fragment exchanges and in vivo suppression to domain II of the 23S rRNA gene of the rrnB operon. Sequence analysis revealed a single base change of G to A at residue 1093, an almost universally conserved base in a highly conserved region known to have specific interactions with ribosomal proteins, elongation factor G, tRNA in the A-site, and the peptidyltransferase region of 23S rRNA. Several avenues of action of the suppressor mutation are suggested, including altered interactions with release factors, ribosomal protein L11, or 16S rRNA. Regardless of the mechanism, the results indicate that a particular residue in 23S rRNA affects peptide chain termination, specifically in decoding of the UGA termination codon. |
| Databáze: | OpenAIRE |
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