Aspartyl-tRNA synthetase with relaxed tRNA specificity since it is able to aspartylate not only its cognate tRNA(Asp) but also tRNA(Asn). This indicates that it is not able to differentiate between base C36 in the tRNA(Asp) anticodon (GUC) from base U36 in the tRNA(Asn) (anticodon GUU). Reaction proceeds in two steps: L-aspartate is first activated by ATP to form Asp-AMP and then transferred to the acceptor end of tRNA(Asp/Asn). ATP + L-aspartate + tRNA(Asx) = AMP + diphosphate + L-aspartyl-tRNA(Asx) Binds 3 Mg(2+) cations per subunit. The strongest magnesium site (Mg1) is bound to the beta- and gamma-phosphates of ATP and four water molecules complete its coordination sphere. Homodimer. The misacylated aspartate-tRNA(Asn) is not used in protein synthesis until it is converted by GatCAB into asparaginyl-tRNA(Asn). Belongs to the class-II aminoacyl-tRNA synthetase family. Type 2 subfamily.