Family

Prolyl-tRNA synthetase, class IIa, type 1 (IPR023717)

Short name: Pro-tRNA-Synthase_IIa_type1

Overlapping homologous superfamilies

Family relationships

Description

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].

Proline-tRNA ligase (also known as Prolyl-tRNA synthetase) belongs to class IIa. Proline-tRNA ligase(EC:6.1.1.15) exists in two forms, which are loosely related. The first form is present in the majority of eubacteria species. The second one, present in some eubacteria, is essentially present in archaea and eukaryota.

The prolyl-tRNA synthetase form presents in most eubacteria can be divided in 2 types. This entry represents type 1. This family includes the enzyme from Escherichia coli that contains all three of the conserved consensus motifs characteristic of class II aminoacyl-tRNA synthetases [PMID: 9062123].

GO terms

Biological Process

GO:0006433 prolyl-tRNA aminoacylation

Molecular Function

GO:0005524 ATP binding
GO:0004827 proline-tRNA ligase activity

Cellular Component

GO:0005737 cytoplasm

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
HAMAP
PIRSF