| Type: | Domain | Name: | Glutamyl/glutaminyl-tRNA synthetase, class Ib, catalytic domain |
| Description: | The aminoacyl-tRNA synthetase (also known as aminoacyl-tRNA ligase) catalyse the attachment of an amino acid to its cognate transfer RNA molecule in a highly specific two-step reaction. These proteins differ widely in size and oligomeric state, and have limited sequence homology []. 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 []. Class II aminoacyl-tRNA synthetases share an anti-parallel beta-sheet fold flanked by alpha-helices [], and are mostly dimeric or multimeric, containing at least three conserved regions [, , ]. 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 and valine belong to class I synthetases. The synthetases specific for alanine, asparagine, aspartic acid, glycine, histidine, lysine, phenylalanine, proline, serine, and threonine 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.Glutamate-tRNA ligase (also known as glutamyl-tRNA synthetase)() 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 coliGlnRS, whereas the C-terminal half exhibits a GluRS-specific structure []. | Short Name: | Glu/Gln-tRNA-synth_Ib_cat-dom |
| DB identifier | Type | Name |
|---|---|---|
| IPR004526 | Family | Glutamyl-tRNA synthetase, archaeal/eukaryotic cytosolic |
| IPR004527 | Family | Glutamate-tRNA ligase, bacterial/mitochondrial |
| IPR000924 | Family | Glutamyl/glutaminyl-tRNA synthetase |
| IPR004514 | Family | Glutamine-tRNA synthetase |
| IPR022380 | Family | Glutamyl-Q tRNA(Asp) synthetase |
| GO Term | Gene Name |
|---|---|
| GO:0005524 | IPR020058 |
| GO:0016876 | IPR020058 |
| GO:0043039 | IPR020058 |
