Release factor-dependent ribosome rescue by BrfA in the Gram-positive bacterium Bacillus subtilis

Nat Commun. 2019 Nov 27;10(1):5397. doi: 10.1038/s41467-019-13408-7.


Rescue of the ribosomes from dead-end translation complexes, such as those on truncated (non-stop) mRNA, is essential for the cell. Whereas bacteria use trans-translation for ribosome rescue, some Gram-negative species possess alternative and release factor (RF)-dependent rescue factors, which enable an RF to catalyze stop-codon-independent polypeptide release. We now discover that the Gram-positive Bacillus subtilis has an evolutionarily distinct ribosome rescue factor named BrfA. Genetic analysis shows that B. subtilis requires the function of either trans-translation or BrfA for growth, even in the absence of proteotoxic stresses. Biochemical and cryo-electron microscopy (cryo-EM) characterization demonstrates that BrfA binds to non-stop stalled ribosomes, recruits homologous RF2, but not RF1, and induces its transition into an open active conformation. Although BrfA is distinct from E. coli ArfA, they use convergent strategies in terms of mode of action and expression regulation, indicating that many bacteria may have evolved as yet unidentified ribosome rescue systems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / genetics*
  • Bacillus subtilis / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • CRISPR-Cas Systems
  • Cryoelectron Microscopy
  • Escherichia coli Proteins / genetics
  • Gene Expression Regulation, Bacterial
  • Microorganisms, Genetically-Modified
  • Peptide Termination Factors / chemistry
  • Peptide Termination Factors / genetics
  • Peptide Termination Factors / metabolism
  • Protein Biosynthesis
  • Protein Conformation
  • RNA, Transfer, Amino Acyl / metabolism
  • RNA-Binding Proteins / genetics
  • Ribosomes / genetics
  • Ribosomes / metabolism*


  • ArfA protein, E coli
  • Bacterial Proteins
  • Escherichia coli Proteins
  • Peptide Termination Factors
  • RNA, Transfer, Amino Acyl
  • RNA-Binding Proteins
  • peptide chain termination release factor 2
  • tRNA, peptidyl-