{Reference Type}: Journal Article
{Title}: Gly56 in the synthetic site of isoleucyl-tRNA synthetase confers specificity and maintains communication with the editing site.
{Author}: Dulic M;Krpan N;Gruic-Sovulj I;
{Journal}: FEBS Lett
{Volume}: 597
{Issue}: 24
{Year}: 2023 12 28
{Factor}: 3.864
{DOI}: 10.1002/1873-3468.14780
{Abstract}: Isoleucyl-tRNA synthetase (IleRS) links isoleucine to cognate tRNA via the Ile-AMP intermediate. Non-cognate valine is often mistakenly recognized as the IleRS substrate; therefore, to maintain the accuracy of translation, IleRS hydrolyzes Val-AMP within the synthetic site (pre-transfer editing). As this activity is not efficient enough, Val-tRNAIle is formed and hydrolyzed in the distant post-transfer editing site. A strictly conserved synthetic site residue Gly56 was previously shown to safeguard Ile-to-Val discrimination during aminoacyl (aa)-AMP formation. Here, we show that the Gly56Ala variant lost its specificity in pre-transfer editing, confirming that this residue ensures the selectivity of all synthetic site reactions. Moreover, we found that the Gly56Ala mutation affects IleRS interaction with aa-tRNA likely by disturbing tRNA-dependent communication between the two active sites.