4v9i
From Proteopedia
Crystal structure of thermus thermophilus 70S in complex with tRNAs and mRNA containing a pseudouridine in a stop codon
Structural highlights
FunctionRL22_THET8 This protein binds specifically to 23S rRNA; its binding is stimulated by other ribosomal proteins, e.g. L4, L17, and L20. It is important during the early stages of 50S assembly. It makes multiple contacts with different domains of the 23S rRNA in the assembled 50S subunit and ribosome (By similarity).[HAMAP-Rule:MF_01331_B] The globular domain of the protein is one of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit, while an extended beta-hairpin is found that penetrates into the center of the 70S ribosome. This extension seems to form part of the wall of the exit tunnel.[HAMAP-Rule:MF_01331_B] Publication Abstract from PubMedDuring 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 (Psi) 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 A resolution of the 30S ribosomal subunit in complex with the anticodon stem loop of tRNASer bound to the PsiAG stop codon in the A site. The PsiA 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. Unusual base pairing during the decoding of a stop codon by the ribosome.,Fernandez IS, Ng CL, Kelley AC, Wu G, Yu YT, Ramakrishnan V Nature. 2013 Jun 30. doi: 10.1038/nature12302. PMID:23812587[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations No citations found See AlsoReferences
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