The 2′-OH group of the peptidyl-tRNA stabilizes an active conformation of the ribosomal PTC

Hani S. Zaher, Jeffrey J. Shaw, Scott A. Strobel, Rachel Green

Research output: Contribution to journalArticle

Abstract

The ribosome accelerates the rate of peptidyl transfer by >10 6-fold relative to the background rate. A widely accepted model for this rate enhancement invokes entropic effects whereby the ribosome and the 2′-OH of the peptidyl-tRNA substrate precisely position the reactive moieties through an extensive network of hydrogen bonds that allows proton movement through them. Some studies, however, have called this model into question because they find the 2′-OH of the peptidyl-tRNA to be dispensable for catalysis. Here, we use an in vitro reconstituted translation system to resolve these discrepancies. We find that catalysis is at least 100-fold slower with the dA76-substituted peptidyl-tRNA substrate and that the peptidyl transferase centre undergoes a slow inactivation when the peptidyl-tRNA lacks the 2′-OH group. Additionally, the 2′-OH group was found to be critical for EFTu binding and peptide release. These findings reconcile the conflict in the literature, and support a model where interactions between active site residues and the 2′-OH of A76 of the peptidyl-tRNA are pivotal in orienting substrates in this active site for optimal catalysis.

Original languageEnglish (US)
Pages (from-to)2445-2453
Number of pages9
JournalThe EMBO journal
Volume30
Issue number12
DOIs
StatePublished - May 2011

Fingerprint

Factor IX
Conformations
Catalysis
Ribosomes
Catalytic Domain
Substrates
Peptidyl Transferases
Protons
Hydrogen
Hydrogen bonds
peptidyl-tRNA
Peptides

Keywords

  • 2′-OH
  • mechanism
  • peptidyl transfer
  • peptidyl-tRNA
  • ribosome

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Neuroscience(all)
  • Medicine(all)

Cite this

The 2′-OH group of the peptidyl-tRNA stabilizes an active conformation of the ribosomal PTC. / Zaher, Hani S.; Shaw, Jeffrey J.; Strobel, Scott A.; Green, Rachel.

In: The EMBO journal, Vol. 30, No. 12, 05.2011, p. 2445-2453.

Research output: Contribution to journalArticle

Zaher, Hani S. ; Shaw, Jeffrey J. ; Strobel, Scott A. ; Green, Rachel. / The 2′-OH group of the peptidyl-tRNA stabilizes an active conformation of the ribosomal PTC. In: The EMBO journal. 2011 ; Vol. 30, No. 12. pp. 2445-2453.
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