Evidence for functional interaction between elongation factor Tu and 16S ribosomal RNA

Ted Powers, Harry F. Noller

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

Translation of the genetk code requires the accurate selection of elongation factor (EF)-Tu·GTP·tRNA ternary complexes at the ribosomal acceptor site, or A site. Several independent lines of evidence have implicated the universally conserved 530 loop of 16S rRNA in this process; yet its precise role has not been identified. Using an allele-specific chemical probing strategy, we have examined the functional defect caused by a dominant lethal G → A substitution at position 530. We find that mutant ribosomes are impaired in EF-Tu-dependent binding of aminoacyl-tRNA in vitro; in contrast, nonenzymatic binding of tRNA to the A and P sites is unaffected, indicating that the defect involves an EF-Tu-related function rather than tRNA-ribosome interactions per se. In vivo, the mutant ribosomes are found in polysomes at low levels and contain reduced amounts of A-site-bound tRNA, but normal levels of P-site tRNA, in agreement with the in vitro results; thus the dominant lethal phenotype of mutations at G530 can be explained by impaired interaction of mutant ribosomes with ternary complex. These results provide evidence for a newly defined function of 16S rRNA - namely, modulation of EF-Tu activity during translation.

Original languageEnglish (US)
Pages (from-to)1364-1368
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume90
Issue number4
StatePublished - Feb 15 1993

Keywords

  • Aminoacyl-tRNA
  • Dominant lethal mutations
  • Protein S12
  • Ribosomal A site
  • Translational accuracy

ASJC Scopus subject areas

  • General
  • Genetics

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