Cryo-EM structure of the hibernating Thermus thermophilus 100S ribosome reveals a protein-mediated dimerization mechanism. Issue 1 (December 2018)

• Record Type: Journal Article
• Authors: Flygaard, Rasmus; Boegholm, Niels; Yusupov, Marat; Jenner, Lasse
• Is Part Of: Nature communications. Volume 9:Issue 1(2018)
• Page Start: 1
• Page End: 12
• Publication Date: 2018-12
• Subjects: Biology -- Periodicals; Physical sciences -- Periodicals; 505
• DOI: 10.1038/s41467-018-06724-x
• Languages: English
• ISSNs: 2041-1723

Abstract

Abstract In response to cellular stresses bacteria conserve energy by dimerization of ribosomes into inactive hibernating 100S ribosome particles. Ribosome dimerization inThermus thermophilus is facilitated by hibernation-promoting factor (Tt HPF). In this study we demonstrate high sensitivity ofTt 100S formation to the levels ofTt HPF and show that a 1:1 ratio leads to optimal dimerization. We report structures of theT. 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 theTt HPF 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 forThermus thermophilus no ribosome-ribosome interactions are involved in the interface. During stress conditions bacterial ribosomes dimerize and form inactive but stable hibernating 100S particles, a process that is facilitated by the hibernation-promoting factor (HPF). Here the authors analyze 100S dimer formation as a function of HPF protein concentration and present theThermus thermophilus 100S ribosome cryo-EM structure.