Asparate--tRNA ligases in this family may be discriminating (6.1.1.12) or nondiscriminating (6.1.1.23). In a multiple sequence alignment of representative asparaginyl-tRNA synthetases (asnS), archaeal/eukaryotic type aspartyl-tRNA synthetases (aspS_arch), and bacterial type aspartyl-tRNA synthetases (aspS_bact), there is a striking similarity between asnS and aspS_arch in gap pattern and in sequence, and a striking divergence of aspS_bact. Consequently, a separate model was built for each of the three groups. This model, aspS_bact, represents aspartyl-tRNA synthetases from the Bacteria and from mitochondria. In some species, this enzyme aminoacylates tRNA for both Asp and Asn; Asp-tRNA(asn) is subsequently transamidated to Asn-tRNA(asn). This model generates very low scores for the archaeal type of aspS and for asnS; scores between the trusted and noise cutoffs represent fragmentary sequences. [Protein synthesis, tRNA aminoacylation]
Jiyao W et al.(2023). "The conserved domain database in 2023.",