On the Mechanism and Origin of Isoleucyl-tRNA Synthetase Editing against Norvaline

摘要

Aminoacyl-tRNA synthetases (aaRSs), the enzymes responsible for coupling tRNAs to their cognate amino acids, minimize translational errors by intrinsic hydrolytic editing. Here, we compared norvaline (Nva), a linear amino acid not coded for protein synthesis, to the proteinogenic, branched valine (Val) in their propensity to mistranslate isoleucine (lie) in proteins. We show that in the synthetic site of isoleucyl-tRNA synthetase (lleRS), Nva and Val are activated and transferred to tRNA at similar rates. The efficiency of the synthetic site in pre-transfer editing of Nva and Val also appears to be similar.