PMID: 15558052
Authors:
Murphy FV 4th, Ramakrishnan V, Malkiewicz A, Agris PF
Title:
The role of modifications in codon discrimination by tRNA(Lys)UUU.
Journal:
Nat Struct Mol Biol. 2004 Dec;11(12):1186-91. Epub 2004 Nov 21.
Abstract:
The natural modification of specific nucleosides in many tRNAs is essential during decoding of mRNA by the ribosome. For example, tRNA(Lys)(UUU) requires the modification N6-threonylcarbamoyladenosine at position 37 (t(6)A37), adjacent and 3' to the anticodon, to bind AAA in the A site of the ribosomal 30S subunit. Moreover, it can only bind both AAA and AAG lysine codons when doubly modified with t(6)A37 and either 5-methylaminomethyluridine or 2-thiouridine at the wobble position (mnm(5)U34 or s(2)U34). Here we report crystal structures of modified tRNA anticodon stem-loops bound to the 30S ribosomal subunit with lysine codons in the A site. These structures allow the rationalization of how modifications in the anticodon loop enable decoding of both lysine codons AAA and AAG.