Drug sensing by the ribosome induces translational arrest via active site perturbation

Mol Cell. 2014 Nov 6;56(3):446-452. doi: 10.1016/j.molcel.2014.09.014. Epub 2014 Oct 8.

Abstract

During protein synthesis, nascent polypeptide chains within the ribosomal tunnel can act in cis to induce ribosome stalling and regulate expression of downstream genes. The Staphylococcus aureus ErmCL leader peptide induces stalling in the presence of clinically important macrolide antibiotics, such as erythromycin, leading to the induction of the downstream macrolide resistance methyltransferase ErmC. Here, we present a cryo-electron microscopy (EM) structure of the erythromycin-dependent ErmCL-stalled ribosome at 3.9 Å resolution. The structure reveals how the ErmCL nascent chain directly senses the presence of the tunnel-bound drug and thereby induces allosteric conformational rearrangements at the peptidyltransferase center (PTC) of the ribosome. ErmCL-induced perturbations of the PTC prevent stable binding and accommodation of the aminoacyl-tRNA at the A-site, leading to inhibition of peptide bond formation and translation arrest.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry
  • Catalytic Domain
  • Cryoelectron Microscopy
  • Erythromycin / chemistry*
  • Models, Molecular
  • Peptide Fragments / chemistry
  • Protein Binding
  • Protein Biosynthesis*
  • Protein Sorting Signals
  • Protein Structure, Quaternary
  • Protein Synthesis Inhibitors / chemistry*
  • Ribosomes / chemistry*
  • Ribosomes / physiology

Substances

  • Bacterial Proteins
  • Peptide Fragments
  • Protein Sorting Signals
  • Protein Synthesis Inhibitors
  • Erythromycin