| Type: | Domain | Name: | TrmE-type guanine nucleotide-binding domain |
| Description: | The P-loop guanosine triphosphatases (GTPases) control amultitude of biological processes, ranging from cell division, cell cycling, and signal transduction, to ribosome assembly and protein synthesis. GTPasesexert their control by interchanging between an inactive GDP-bound state and an active GTP-bound state, thereby acting as molecular switches. The commondenominator of GTPases is the highly conserved guanine nucleotide-binding (G) domain that is responsible for binding and hydrolysis of guanine nucleotides.TrmE (also called MnmE) contains a canonical G domain and is conserved in all three kingdoms of life. It is involved in the modification of uridine bases(U34) at the first anticodon (wobble) position of tRNAs decoding two-family box triplets. TrmE is organised as a multidomain protein consisting of an~220-amino acid N-terminal domain, probably required for self-assembly, a middle GTPase domain, of about 160 residues, and an ~75-amino acid C-terminaldomain, which contains a highly conserved CxGK motif. TrmE contains at least four of the five conserved nucleotide-binding motifs G1 (GxxxxGK[ST]or P- loop), G2 (T), G3 (DxxG) and G4 ([NT]KxD). The totally invariant alanine in the SA[KL](G5) motif of Ras anGalph proteins is less well conserved [, , , , ].The structure of the TrmE-type G domain consists of a central four-stranded beta-sheet flanked by five alpha-helices. It dimerises in apotassium-dependent manner [, ].This entry represents the TmrE-type G domain. | Short Name: | G_TrmE |
