This domain is found in GatB. It is about 140 amino acid residues long. This domain is found at the C terminus of GatB O30509 which transamidates Glu-tRNA to Gln-tRNA.
The GatB domain, the function of which is uncertain, is associated with aspartyl/glutamyl amidotransferase subunit B and glutamyl amidotransferase subunit E. These are involved in the formation of correctly charged Asn-tRNA(Asn) or Gln-tRNA(Gln) through the transamidation of misacylated Asp-tRNA(Asn) or Glu-tRNA(Gln) in organisms which lack either or both of asparaginyl-tRNA or glutaminyl-tRNA synthetases. The reaction takes place in the presence of glutamine and ATP through an activated phospho-Asp-tRNA(Asn) or phospho-Glu-tRNA(Gln).