Cryo-EM structure of the hibernating Thermus thermophilus 100S ribosome reveals a protein-mediated dimerization mechanism

Nat Commun. 2018 Oct 9;9(1):4179. doi: 10.1038/s41467-018-06724-x.


In response to cellular stresses bacteria conserve energy by dimerization of ribosomes into inactive hibernating 100S ribosome particles. Ribosome dimerization in Thermus thermophilus is facilitated by hibernation-promoting factor (TtHPF). In this study we demonstrate high sensitivity of Tt100S formation to the levels of TtHPF and show that a 1:1 ratio leads to optimal dimerization. We report structures of the T. thermophilus 100S ribosome determined by cryo-electron microscopy to average resolutions of 4.13 Å and 4.57 Å. In addition, we present a 3.28 Å high-resolution cryo-EM reconstruction of a 70S ribosome from a hibernating ribosome dimer and reveal a role for the linker region connecting the TtHPF N- and C-terminal domains in translation inhibition by preventing Shine-Dalgarno duplex formation. Our work demonstrates that species-specific differences in the dimerization interface govern the overall conformation of the 100S ribosome particle and that for Thermus thermophilus no ribosome-ribosome interactions are involved in the interface.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / metabolism*
  • Cryoelectron Microscopy*
  • DNA-Directed RNA Polymerases / metabolism
  • Dimerization*
  • Models, Molecular
  • Protein Domains
  • Protein Subunits / chemistry
  • Protein Subunits / metabolism
  • Ribosomes / metabolism
  • Ribosomes / ultrastructure*
  • Thermus thermophilus / metabolism*


  • Bacterial Proteins
  • Protein Subunits
  • DNA-Directed RNA Polymerases