Structure of the Bacillus subtilis 70S ribosome reveals the basis for species-specific stalling

Nat Commun. 2015 Apr 23;6:6941. doi: 10.1038/ncomms7941.

Abstract

Ribosomal stalling is used to regulate gene expression and can occur in a species-specific manner. Stalling during translation of the MifM leader peptide regulates expression of the downstream membrane protein biogenesis factor YidC2 (YqjG) in Bacillus subtilis, but not in Escherichia coli. In the absence of structures of Gram-positive bacterial ribosomes, a molecular basis for species-specific stalling has remained unclear. Here we present the structure of a Gram-positive B. subtilis MifM-stalled 70S ribosome at 3.5-3.9 Å, revealing a network of interactions between MifM and the ribosomal tunnel, which stabilize a non-productive conformation of the PTC that prevents aminoacyl-tRNA accommodation and thereby induces translational arrest. Complementary genetic analyses identify a single amino acid within ribosomal protein L22 that dictates the species specificity of the stalling event. Such insights expand our understanding of how the synergism between the ribosome and the nascent chain is utilized to modulate the translatome in a species-specific manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis*
  • Bacterial Proteins
  • Crystallography, X-Ray
  • Gene Expression Regulation, Bacterial*
  • Membrane Proteins / genetics
  • Molecular Conformation
  • Protein Biosynthesis / genetics*
  • Protein Sorting Signals / genetics
  • RNA, Transfer
  • Ribosomal Proteins
  • Ribosomes / chemistry*

Substances

  • Bacterial Proteins
  • Membrane Proteins
  • Protein Sorting Signals
  • Ribosomal Proteins
  • RNA, Transfer

Associated data

  • PDB/3J9W