3J6X

S. cerevisiae 80S ribosome bound with Taura syndrome virus (TSV) IRES, 5 degree rotation (Class II)

This is a non-PDB format compatible entry.

Summary for 3J6X

• Entry DOI: 10.2210/pdb3j6x/pdb
• Related: 3J6Y 3U5D
• EMDB information: 5942 5943
• Descriptor: 25S ribosomal RNA, 60S ribosomal protein L7, 60S ribosomal protein L8, ... (80 entities in total)
• Functional Keywords: translation initiation, ribosome, intergenic ires, tsv ires
• Biological source: Saccharomyces cerevisiae (yeast); More
• Total number of polymer chains: 80
• Total formula weight: 3194034.32

Authors

Koh, C.S.,Brilot, A.F.,Grigorieff, N.,Korostelev, A.A. (deposition date: 2014-04-16, release date: 2014-06-11, Last modification date: 2024-02-21)

Primary citation

Koh, C.S.,Brilot, A.F.,Grigorieff, N.,Korostelev, A.A.
Taura syndrome virus IRES initiates translation by binding its tRNA-mRNA-like structural element in the ribosomal decoding center.
Proc.Natl.Acad.Sci.USA, 111:9139-9144, 2014

PubMed Abstract: In cap-dependent translation initiation, the open reading frame (ORF) of mRNA is established by the placement of the AUG start codon and initiator tRNA in the ribosomal peptidyl (P) site. Internal ribosome entry sites (IRESs) promote translation of mRNAs in a cap-independent manner. We report two structures of the ribosome-bound Taura syndrome virus (TSV) IRES belonging to the family of Dicistroviridae intergenic IRESs. Intersubunit rotational states differ in these structures, suggesting that ribosome dynamics play a role in IRES translocation. Pseudoknot I of the IRES occupies the ribosomal decoding center at the aminoacyl (A) site in a manner resembling that of the tRNA anticodon-mRNA codon. The structures reveal that the TSV IRES initiates translation by a previously unseen mechanism, which is conceptually distinct from initiator tRNA-dependent mechanisms. Specifically, the ORF of the IRES-driven mRNA is established by the placement of the preceding tRNA-mRNA-like structure in the A site, whereas the 40S P site remains unoccupied during this initial step.

PubMed: 24927574
DOI: 10.1073/pnas.1406335111

Experimental method

ELECTRON MICROSCOPY (6.1 Å)