Class II tRNA amino-acyl synthetase-like catalytic core domain. Class II amino acyl-tRNA synthetases (aaRS) share a common fold and generally attach an amino acid to the 3' OH of ribose of the appropriate tRNA. PheRS is an exception in that it attaches the amino acid at the 2'-OH group, like class I aaRSs. These enzymes are usually homodimers. This domain is primarily responsible for ATP-dependent formation of the enzyme bound aminoacyl-adenylate. The substrate specificity of this reaction is further determined by additional domains. Intererestingly, this domain is also found is asparagine synthase A (AsnA), in the accessory subunit of mitochondrial polymerase gamma and in the bacterial ATP phosphoribosyltransferase regulatory subunit HisZ.
Jiyao W et al.(2023). "The conserved domain database in 2023.",