Download MendeleyUnusual base pairing during the decoding of a stop codon by the ribosome.
Fernandez, I.S., Ng, C.L., Kelley, A.C., Wu, G., Yu, Y.T., Ramakrishnan, V.(2013) Nature 500: 107-110
- PubMed: 23812587 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1038/nature12302
- Primary Citation Related Structures:
4JV5, 4JYA, 4K0K, 4V9I - PubMed Abstract:
During normal translation, the binding of a release factor to one of the three stop codons (UGA, UAA or UAG) results in the termination of protein synthesis. However, modification of the initial uridine to a pseudouridine (Ψ) allows efficient recognition and read-through of these stop codons by a transfer RNA (tRNA), although it requires the formation of two normally forbidden purine-purine base pairs. Here we determined the crystal structure at 3.1 Å resolution of the 30S ribosomal subunit in complex with the anticodon stem loop of tRNA(Ser) bound to the ΨAG stop codon in the A site. The ΨA base pair at the first position is accompanied by the formation of purine-purine base pairs at the second and third positions of the codon, which show an unusual Watson-Crick/Hoogsteen geometry. The structure shows a previously unsuspected ability of the ribosomal decoding centre to accommodate non-canonical base pairs.
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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