Domain

Glutaminyl-tRNA synthetase, class Ib, non-specific RNA-binding domain, N-terminal (IPR007639)

Short name: Gln-tRNA-synth_Ib_RNA-bd_N

Domain relationships

None.

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 [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 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.

This is a domain found N-terminal to the catalytic domain of glutaminyl-tRNA synthetase (EC:6.1.1.18) in eukaryotes but not in Escherichia coli. This domain is thought to bind RNA in a non-specific manner, enhancing interactions between the tRNA and enzyme, but is not essential for enzyme function [PMID: 10347214].

GO terms

Biological Process

GO:0006418 tRNA aminoacylation for protein translation

Molecular Function

GO:0005524 ATP binding
GO:0004812 aminoacyl-tRNA ligase activity
GO:0000166 nucleotide binding

Cellular Component

GO:0005737 cytoplasm

Contributing signatures

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