6SGC

Rabbit 80S ribosome stalled on a poly(A) tail

This is a non-PDB format compatible entry.

Summary for 6SGC

• Entry DOI: 10.2210/pdb6sgc/pdb
• EMDB information: 10181
• Descriptor: 18S ribosomal RNA, 40S ribosomal protein S8, Ribosomal protein S9 (Predicted), ... (88 entities in total)
• Functional Keywords: protein translation, ribosome stalling, polya tail, ribosome
• Biological source: Homo sapiens; More
• Total number of polymer chains: 86
• Total formula weight: 3468047.78

Authors

Chandrasekaran, V.,Juszkiewicz, S.,Choi, J.,Puglisi, J.D.,Brown, A.,Shao, S.,Ramakrishnan, V.,Hegde, R.S. (deposition date: 2019-08-03, release date: 2019-12-04, Last modification date: 2022-03-30)

Primary citation

Chandrasekaran, V.,Juszkiewicz, S.,Choi, J.,Puglisi, J.D.,Brown, A.,Shao, S.,Ramakrishnan, V.,Hegde, R.S.
Mechanism of ribosome stalling during translation of a poly(A) tail.
Nat.Struct.Mol.Biol., 26:1132-1140, 2019

PubMed Abstract: Faulty or damaged messenger RNAs are detected by the cell when translating ribosomes stall during elongation and trigger pathways of mRNA decay, nascent protein degradation and ribosome recycling. The most common mRNA defect in eukaryotes is probably inappropriate polyadenylation at near-cognate sites within the coding region. How ribosomes stall selectively when they encounter poly(A) is unclear. Here, we use biochemical and structural approaches in mammalian systems to show that poly-lysine, encoded by poly(A), favors a peptidyl-transfer RNA conformation suboptimal for peptide bond formation. This conformation partially slows elongation, permitting poly(A) mRNA in the ribosome's decoding center to adopt a ribosomal RNA-stabilized single-stranded helix. The reconfigured decoding center clashes with incoming aminoacyl-tRNA, thereby precluding elongation. Thus, coincidence detection of poly-lysine in the exit tunnel and poly(A) in the decoding center allows ribosomes to detect aberrant mRNAs selectively, stall elongation and trigger downstream quality control pathways essential for cellular homeostasis.

PubMed: 31768042
DOI: 10.1038/s41594-019-0331-x

Experimental method

ELECTRON MICROSCOPY (2.8 Å)