The structural basis for specific decoding of AUA by isoleucine tRNA on the ribosome

Decoding of the AUA isoleucine codon in bacteria and archaea requires modification of a C in the anticodon wobble position of the isoleucine tRNA. Here, we report the crystal structure of the archaeal tRNA2(Ile), which contains the modification agmatidine in its anticodon, in complex with the AUA codon on the 70S ribosome. The structure illustrates how agmatidine confers codon specificity for AUA over AUG.