GatFAB is a trimeric tRNA-dependent amidotransferase (AdT) that allows the formation of correctly charged Gln-tRNA(Gln) through the transamidation of misacylated Glu-tRNA(Gln) in the mitochondria [1,2]. The reaction takes place in the presence of glutamine and ATP through an activated gamma-phospho-Glu-tRNA(Gln). This family represents GatF (also known as GFT1), an essential subunit of the yeast tRNA-dependent amidotransferase [1]. GatF is a fungi-specific orthologue of the GatC subunit found in all other known heterotrimeric AdTs (GatCAB) [3]. GatF C-terminal encircles the GatA-GatB interface in the same manner as GatC to maintain GatA-GatB assembly, whereas the N-terminal region mediates additional hydrophobic and hydrophilic interactions with GatA [3], which may modulate GatA folding and stability [3].

1: Characterization of Gtf1p, the connector subunit of yeast mitochondrial tRNA-dependent amidotransferase. Barros MH, Rak M, Paulela JA, Tzagoloff A; J Biol Chem. 2011;286:32937-32947. PMID:21799017

2: Yeast mitochondrial Gln-tRNA(Gln) is generated by a GatFAB-mediated transamidation pathway involving Arc1p-controlled subcellular sorting of cytosolic GluRS. Frechin M, Senger B, Braye M, Kern D, Martin RP, Becker HD; Genes Dev. 2009;23:1119-1130. PMID:19417106

3: Crystal structure of Saccharomyces cerevisiae mitochondrial GatFAB reveals a novel subunit assembly in tRNA-dependent amidotransferases. Araiso Y, Huot JL, Sekiguchi T, Frechin M, Fischer F, Enkler L, Senger B, Ishitani R, Becker HD, Nureki O; Nucleic Acids Res. 2014;42:6052-6063. PMID:24692665