Role of Queuosine in Codon-Anticodon Interaction

Abstract

The speed and accuracy of the process of protein synthesis is very high. The major step at which the fidelity of translation is governed is at the step of codon?anticodon pairing. An erroneous codon?anticodon pairing can prove to be disastrous for the cell. The translational machinery employs various mechanisms to ensure proper codon?anticodon pairing. The ribosomal conformational changes necessary for proper translation occur only upon correct codon?anticodon pairing. To gain deeper insights into the mechanisms of codon?anticodon interaction, queuosine, a modified nucleoside present in few tRNAs, was chosen. Using mutant initiator tRNA capable of incorporating queuosine, we have shown that queuosine plays a role in codon?anticodon interaction at the P?site of the ribosome. We have demonstrated that methylations in ribosomal RNAs, especially at position 966 (m²G966) in 16S rRNA, play an important role in codon?anticodon interaction. This methylated base does not allow very bulky groups at the wobble position in the anticodon of initiator tRNA. Taken together, our in vivo analysis suggests that m²G966 might be responsible for maintenance of correct codon?anticodon interaction at the P?site of the ribosome.