Structure of an archaeal non-discriminating glutamyl-tRNA synthetase: a missing link in the evolution of Gln-tRNAGln formation.

The molecular basis of the genetic code relies on the specific ligation of amino acids to their cognate tRNA molecules. However, two pathways exist for the formation of Gln-tRNA(Gln). The evolutionarily older indirect route utilizes a non-discriminating glutamyl-tRNA synthetase (ND-GluRS) that can form both Glu-tRNA(Glu) and Glu-tRNA(Gln).