How a circularized tmRNA moves through the ribosome

Science. 2019 Feb 15;363(6428):740-744. doi: 10.1126/science.aav9370.

Abstract

During trans-translation, transfer-messenger RNA (tmRNA) and small protein B (SmpB) together rescue ribosomes stalled on a truncated mRNA and tag the nascent polypeptide for degradation. We used cryo-electron microscopy to determine the structures of three key states of the tmRNA-SmpB-ribosome complex during trans translation at resolutions of 3.7 to 4.4 angstroms. The results show how tmRNA and SmpB act specifically on stalled ribosomes and how the circularized complex moves through the ribosome, enabling translation to switch from the old defective message to the reading frame on tmRNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cryoelectron Microscopy
  • Escherichia coli
  • Motion
  • Protein Biosynthesis*
  • RNA, Bacterial / chemistry*
  • RNA-Binding Proteins / chemistry*
  • Ribosomes / chemistry*
  • Thermus thermophilus

Substances

  • RNA, Bacterial
  • RNA-Binding Proteins
  • small protein B
  • tmRNA