InterPro domain: IPR017959

Glutamyl-tRNA(Gln) amidotransferase (Gat; 6.3.5 ) provides a means of producing correctly charged Gln-tRNA(Gln) through the transamidation of mis-acylated Glu-tRNA(Gln) in organisms which lack glutaminyl-tRNA synthetase [ 1 , 2 ]. The reaction takes place in the presence of glutamine and ATP through an activated gamma-phospho-Glu-tRNA(Gln). The enzyme is composed of three subunits: A (an amidase), B and C. It also exists in eukaryotes as a protein targeted to the mitochondria.

The heterotrimer GatABC is involved in converting Glu to Gln and/or Asp to Asn, when the amino acid is attached to the appropriate tRNA. In Lactobacillus, GatABC is responsible for producing tRNA(Gln). In Archaea, GatABC is responsible for producing tRNA(Asn), while GatDE is responsible for producing tRNA(Gln). In lineages that include Thermus, Chlamydia, or Acidithiobacillus, the GatABC complex catalyses both tRNA(Gln) and tRNA(Asn).

This entry represents aspartyl/glutamyl-tRNA(Asn/Gln) amidotransferase subunit B and glutamyl-tRNA(Gln) amidotransferase subunit E.

1. Glu-tRNAGln amidotransferase: a novel heterotrimeric enzyme required for correct decoding of glutamine codons during translation. Proc. Natl. Acad. Sci. U.S.A. 94, 11819-26
2. Structural basis for tRNA-dependent amidotransferase function. Structure 13, 1421-33