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Initiation-shift of trans-translation by aminoglycosides

Takayuki Konno1, Daisuke Kurita, Toshiharu Takahashi

  • 1Department of Biochemistry and Biotechnology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki 036-8561, Japan.

Nucleic Acids Symposium Series (2004)
|December 8, 2006
PubMed

Insights

Paromomycin antibiotics inhibit trans-translation by binding tmRNA, affecting its dual tRNA/mRNA function. This study reveals paromomycin

Area of Science:

  • Molecular Biology
  • Microbiology
  • Biochemistry

Background:

  • Trans-translation is a unique cellular mechanism that rescues stalled ribosomes.
  • tmRNA (transfer-messenger RNA) acts as both a tRNA and mRNA, facilitating the release of stalled translation.
  • Aminoglycoside antibiotics are known to interfere with bacterial translation.

Purpose of the Study:

  • To investigate the in vitro effects of aminoglycoside antibiotics on the trans-translation process.
  • To elucidate the specific binding sites and mechanisms of action of paromomycin on tmRNA.
  • To understand how paromomycin affects the function of tmRNA in rescuing stalled ribosomes.

Main Methods:

  • In vitro assays were used to study the effects of paromomycin on trans-translation.
  • Chemical footprinting was employed to identify paromomycin binding sites on tmRNA.
  • Mutational analysis of 16S rRNA and tmRNA was performed to assess the impact on paromomycin's effects.

Main Results:

  • Paromomycin binds to tmRNA in both the tRNA domain and a helical region between the tRNA and mRNA domains.
  • Binding in the tRNA domain inhibits aminoacylation, an effect partially rescued by SmpB (a tmRNA-binding protein).
  • Paromomycin induces a -1 shift in the translation-resuming point on tmRNA, dependent on 16S rRNA but not tmRNA mutations.

Conclusions:

  • Paromomycin interferes with trans-translation through distinct mechanisms compared to its action on canonical translation.
  • The binding of paromomycin to tmRNA and its subsequent effect on the initiation site represent a novel mode of antibiotic action.
  • Understanding these interactions could lead to the development of new antibiotics targeting bacterial translation.

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