v5.1.0.3
Cicer data from the Legume Information System
Type | Family |
Description | Proline-tRNA ligase (also known as Prolyl-tRNA synthetase) is a class II tRNA ligase and is recognised by , which recognises tRNA ligases for Gly, His, Ser, and Pro. The proline-tRNA ligases are divided into two widely divergent families. This family includes the archaeal enzyme, the Pro-specific domain of a human multifunctional tRNA ligase, and the enzyme from the spirochete Borrelia burgdorferi (Lyme desease spirochete). The other family, , includes enzymes from Escherichia coli, Bacillus subtilis, Synechocystis sp. (strain PCC 6308), and one of the two proline-tRNA ligases of Saccharomyces cerevisiae (Baker's yeast). 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 [ , ]. 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 β-sheet fold flanked by α-helices [], and are mostly dimeric or multimeric, containing at least three conserved regions [, , ]. However, tRNA binding involves an α-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 []. |
Short Name | Pro-tRNA-ligase_IIa_arc-type |