8fon

Crystal structure of tRNA^Lys(SUU) bound to AUA codon in the ribosomal P site

spinqualitylabelsall models 8fon, resolution 3.64Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8fon is a 20 chain structure with sequence from Thermus thermophilus HB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.64Å Ligands: MG, MNU, PPU, T6A, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RS6_THET8 Located on the outer edge of the platform on the body of the 30S subunit.[HAMAP-Rule:MF_00360] Publication Abstract from PubMed Rapid and accurate translation is essential in all organisms to produce properly folded and functional proteins. mRNA codons that define the protein-coding sequences are decoded by tRNAs on the ribosome in the aminoacyl (A) binding site. The mRNA codon and the tRNA anticodon interaction is extensively monitored by the ribosome to ensure accuracy in tRNA selection. While other polymerases that synthesize DNA and RNA can correct for misincorporations, the ribosome is unable to correct mistakes. Instead, when a misincorporation occurs, the mismatched tRNA-mRNA pair moves to the peptidyl (P) site and, from this location, causes a reduction in the fidelity at the A site, triggering post-peptidyl transfer quality control. This reduced fidelity allows for additional incorrect tRNAs to be accepted and for release factor 2 (RF2) to recognize sense codons, leading to hydrolysis of the aberrant peptide. Here, we present crystal structures of the ribosome containing a tRNA(Lys) in the P site with a U*U mismatch with the mRNA codon. We find that when the mismatch occurs in the second position of the P-site codon-anticodon interaction, the first nucleotide of the A-site codon flips from the mRNA path to engage highly conserved 16S rRNA nucleotide A1493 in the decoding center. We propose that this mRNA nucleotide mispositioning leads to reduced fidelity at the A site. Further, this state may provide an opportunity for RF2 to initiate premature termination before erroneous nascent chains disrupt the cellular proteome. Structural basis for reduced ribosomal A-site fidelity in response to P-site codon-anticodon mismatches.,Nguyen HA, Hoffer ED, Fagan CE, Maehigashi T, Dunham CM J Biol Chem. 2023 Apr;299(4):104608. doi: 10.1016/j.jbc.2023.104608. Epub 2023 , Mar 15. PMID:36924943 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosomal protein THX 3D structures

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