6T7T

Structure of yeast 80S ribosome stalled on poly(A) tract.

This is a non-PDB format compatible entry.

Summary for 6T7T

• Entry DOI: 10.2210/pdb6t7t/pdb
• EMDB information: 10397
• Descriptor: 60S ribosomal protein L2-A, Rps5p, 40S ribosomal protein S6-A, ... (81 entities in total)
• Functional Keywords: stalling dicodon codon pair, translation
• Biological source: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast); More
• Total number of polymer chains: 82
• Total formula weight: 3000039.47

Authors

Tesina, P.,Buschauer, R.,Cheng, J.,Berninghausen, O.,Becker, R.,Beckmann, R. (deposition date: 2019-10-23, release date: 2019-12-25, Last modification date: 2020-02-19)

Primary citation

Tesina, P.,Lessen, L.N.,Buschauer, R.,Cheng, J.,Wu, C.C.,Berninghausen, O.,Buskirk, A.R.,Becker, T.,Beckmann, R.,Green, R.
Molecular mechanism of translational stalling by inhibitory codon combinations and poly(A) tracts.
Embo J., 39:e103365-e103365, 2020

PubMed Abstract: Inhibitory codon pairs and poly(A) tracts within the translated mRNA cause ribosome stalling and reduce protein output. The molecular mechanisms that drive these stalling events, however, are still unknown. Here, we use a combination of in vitro biochemistry, ribosome profiling, and cryo-EM to define molecular mechanisms that lead to these ribosome stalls. First, we use an in vitro reconstituted yeast translation system to demonstrate that inhibitory codon pairs slow elongation rates which are partially rescued by increased tRNA concentration or by an artificial tRNA not dependent on wobble base-pairing. Ribosome profiling data extend these observations by revealing that paused ribosomes with empty A sites are enriched on these sequences. Cryo-EM structures of stalled ribosomes provide a structural explanation for the observed effects by showing decoding-incompatible conformations of mRNA in the A sites of all studied stall- and collision-inducing sequences. Interestingly, in the case of poly(A) tracts, the inhibitory conformation of the mRNA in the A site involves a nucleotide stacking array. Together, these data demonstrate a novel mRNA-induced mechanisms of translational stalling in eukaryotic ribosomes.

PubMed: 31858614
DOI: 10.15252/embj.2019103365

Experimental method

ELECTRON MICROSCOPY (3.1 Å)