InterPro domain: IPR004095

The TGS domain (named for its presence ThrRS, GTPase, and SpoT) is present in a number of enzymes, for example, in threonyl-tRNA synthetase (ThrRS), a distinct family of GTPases (the OBG family), and guanosine-3',5'-bis(diphosphate) 3'-pyrophosphohydrolase (SpoT) [ 1 , 2 ] and synthetase (RelA) which are involved in stringent response in bacteria. The TGS domain is also present at the N-terminal of the uridine kinase from the spirochaete Treponema pallidum [ 3 ] (but not any other organism, including the related spirochaete Borrelia burgdorferi).

TGS is a small domain that consists of ~50 amino acid residues and has nucleic acid binding affinity. It is arranged in a six-stranded half-barrel that curves around an alpha-helix and belongs to the beta-grasp fold superfamily [ 4 , 5 , 6 ]. The function of the TGS domain of SpoT is in transcription of survival and virulence genes in response to environmental stress [ 7 ].

1. Evolution of aminoacyl-tRNA synthetases--analysis of unique domain architectures and phylogenetic trees reveals a complex history of horizontal gene transfer events. Genome Res. 9, 689-710
2. ATP binding by the P-loop NTPase OsYchF1 (an unconventional G protein) contributes to biotic but not abiotic stress responses. Proc. Natl. Acad. Sci. U.S.A. 113, 2648-53
3. Comparative genome analysis of the pathogenic spirochetes Borrelia burgdorferi and Treponema pallidum. Infect. Immun. 68, 1633-48
4. Crystal structure of the YchF protein reveals binding sites for GTP and nucleic acid. J. Bacteriol. 185, 4031-7
5. Human OLA1 defines an ATPase subfamily in the Obg family of GTP-binding proteins. J. Biol. Chem. 282, 19928-37
6. The prokaryotic antecedents of the ubiquitin-signaling system and the early evolution of ubiquitin-like beta-grasp domains. Genome Biol. 7, R60
7. Ribosome-dependent activation of stringent control. Nature 534, 277-280