Class II Histidinyl-tRNA synthetase (HisRS)-like catalytic core domain. HisRS is a homodimer. It is responsible for the attachment of histidine to the 3' OH group of ribose of the appropriate tRNA. This domain is primarily responsible for ATP-dependent formation of the enzyme bound aminoacyl-adenylate. Class II assignment is based upon its structure and the presence of three characteristic sequence motifs. This domain is also found at the C-terminus of eukaryotic GCN2 protein kinase and at the N-terminus of the ATP phosphoribosyltransferase accessory subunit, HisZ. HisZ along with HisG catalyze the first reaction in histidine biosynthesis. HisZ is found only in a subset of bacteria and differs from HisRS in lacking a C-terminal anti-codon binding domain.
Jiyao W et al.(2023). "The conserved domain database in 2023.",