Pathways & interactions
Glutamyl/glutaminyl-tRNA synthetase (IPR000924)
Short name: Glu/Gln-tRNA-synth
Overlapping homologous superfamilies
- Glutamyl/glutaminyl-tRNA synthetase (IPR000924)
- Glutamate-tRNA ligase, bacterial/mitochondrial (IPR004527)
- Glutamine-tRNA synthetase (IPR004514)
- Glutamyl-Q tRNA(Asp) synthetase (IPR022380)
- Glutamyl-tRNA synthetase, archaeal/eukaryotic cytosolic (IPR004526)
The aminoacyl-tRNA synthetases (also known as aminoacyl-tRNA ligases) catalyse the attachment of an amino acid to its cognate transfer RNA molecule in a highly specific two-step reaction [PMID: 10704480,PMID: 12458790]. These proteins differ widely in size and oligomeric state, and have limited sequence homology [PMID: 2203971]. The 20 aminoacyl-tRNA synthetases are divided into two classes, I and II. Class I aminoacyl-tRNA synthetases contain a characteristic Rossman fold catalytic domain and are mostly monomeric [PMID: 10673435]. Class II aminoacyl-tRNA synthetases share an anti-parallel beta-sheet fold flanked by alpha-helices [PMID: 8364025], and are mostly dimeric or multimeric, containing at least three conserved regions [PMID: 8274143, PMID: 2053131, PMID: 1852601]. However, tRNA binding involves an alpha-helical structure that is conserved between class I and class II synthetases. In reactions catalysed by the class I aminoacyl-tRNA synthetases, the aminoacyl group is coupled to the 2'-hydroxyl of the tRNA, while, in class II reactions, the 3'-hydroxyl site is preferred. The synthetases specific for arginine, cysteine, glutamic acid, glutamine, isoleucine, leucine, methionine, tyrosine, tryptophan, valine, and some lysine synthetases (non-eukaryotic group) belong to class I synthetases. The synthetases specific for alanine, asparagine, aspartic acid, glycine, histidine, phenylalanine, proline, serine, threonine, and some lysine synthetases (non-archaeal group), belong to class-II synthetases. Based on their mode of binding to the tRNA acceptor stem, both classes of tRNA synthetases have been subdivided into three subclasses, designated 1a, 1b, 1c and 2a, 2b, 2c [PMID: 10447505].
Glutamate-tRNA ligase (also known as glutamyl-tRNA synthetase; EC:22.214.171.124) is a class Ic ligase and shows several similarities with glutamate-tRNA ligase concerning structure and catalytic properties. It is an alpha2 dimer. To date one crystal structure of a glutamate-tRNA ligase (Thermus thermophilus) has been solved. The molecule has the form of a bent cylinder and consists of four domains. The N-terminal half (domains 1 and 2) contains the 'Rossman fold' typical for class I ligases and resembles the corresponding part of Escherichia coli GlnRS, whereas the C-terminal half exhibits a GluRS-specific structure [PMID: 9426192].
- PR00987 (TRNASYNTHGLU)