5e81

Publication Abstract from PubMed

Posttranscriptional modifications at the wobble position of transfer RNAs play a substantial role in deciphering the degenerate genetic code on the ribosome. The number and variety of modifications suggest different mechanisms of action during messenger RNA decoding, of which only a few were described so far. Here, on the basis of several 70S ribosome complex X-ray structures, we demonstrate how Escherichia coli tRNA(Lys)UUU with hypermodified 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U) at the wobble position discriminates between cognate codons AAA and AAG, and near-cognate stop codon UAA or isoleucine codon AUA, with which it forms pyrimidine-pyrimidine mismatches. We show that mnm(5)s(2)U forms an unusual pair with guanosine at the wobble position that expands general knowledge on the degeneracy of the genetic code and specifies a powerful role of tRNA modifications in translation. Our models consolidate the translational fidelity mechanism proposed previously where the steric complementarity and shape acceptance dominate the decoding mechanism.

Novel base-pairing interactions at the tRNA wobble position crucial for accurate reading of the genetic code.,Rozov A, Demeshkina N, Khusainov I, Westhof E, Yusupov M, Yusupova G Nat Commun. 2016 Jan 21;7:10457. doi: 10.1038/ncomms10457. PMID:26791911^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.