Conformational Control of Translation Termination on the 70S Ribosome

Structure. 2018 Jun 5;26(6):821-828.e3. doi: 10.1016/j.str.2018.04.001. Epub 2018 May 3.

Abstract

Translation termination ensures proper lengths of cellular proteins. During termination, release factor (RF) recognizes a stop codon and catalyzes peptide release. Conformational changes in RF are thought to underlie accurate translation termination. However, structural studies of ribosome termination complexes have only captured RFs in a conformation that is consistent with the catalytically active state. Here, we employ a hyper-accurate RF1 variant to obtain crystal structures of 70S termination complexes that suggest a structural pathway for RF1 activation. We trapped RF1 conformations with the catalytic domain outside of the peptidyl-transferase center, while the codon-recognition domain binds the stop codon. Stop-codon recognition induces 30S decoding-center rearrangements that precede accommodation of the catalytic domain. The separation of codon recognition from the opening of the catalytic domain suggests how rearrangements in RF1 and in the ribosomal decoding center coordinate stop-codon recognition with peptide release, ensuring accurate translation termination.

Keywords: blasticidin S; class I release factors; stop-codon recognition; termination accuracy.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Binding Sites
  • Catalytic Domain
  • Codon, Terminator
  • Models, Molecular
  • Peptide Chain Termination, Translational
  • Peptide Termination Factors / chemistry*
  • Peptide Termination Factors / metabolism*
  • Protein Binding
  • Protein Conformation
  • Ribosome Subunits, Large, Bacterial / chemistry
  • Ribosome Subunits, Large, Bacterial / metabolism
  • Ribosome Subunits, Small, Bacterial / chemistry
  • Ribosome Subunits, Small, Bacterial / metabolism
  • Ribosomes / chemistry*
  • Ribosomes / metabolism*

Substances

  • Codon, Terminator
  • Peptide Termination Factors