InterPro domain: IPR041715

HisRS is a homodimer and 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 [ 1 ]. This domain is also found at the C terminus of eukaryotic GCN2 protein kinase [ 2 ] 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 [ 3 ].

1. The quaternary structure of the HisZ-HisG N-1-(5'-phosphoribosyl)-ATP transferase from Lactococcus lactis. Biochemistry 41, 11838-46
2. The histidyl-tRNA synthetase-related sequence in the eIF-2 alpha protein kinase GCN2 interacts with tRNA and is required for activation in response to starvation for different amino acids. Mol. Cell. Biol. 15, 4497-506
3. An aminoacyl-tRNA synthetase paralog with a catalytic role in histidine biosynthesis. Proc. Natl. Acad. Sci. U.S.A. 96, 8985-90