Protein Domain : IPR002320

Type:  Family Name:  Threonine-tRNA ligase, class IIa
Description:  Threonine-tRNA ligase (also known as Threonyl-tRNA synthetase) () exists as a monomer and belongs to class IIa. The enzyme from Escherichia colirepresses the translation of its own mRNA. The crystal structure of the complex between tRNA(Thr) and ThrRS show structural features that reveal novel strategies for providing specificity in tRNA selection. These include an amino-terminal domain containing a novel protein fold that makes minor groove contacts with the tRNA acceptor stem. The enzyme induces a large deformation of the anticodon loop, resulting in an interaction between two adjacent anticodon bases, which accounts for their prominent role in tRNA identity and translational regulation. A zinc ion found in the active site is implicated in amino acid recognition/discrimination []. The zinc ion may act to ensure that only amino acids that possess a hydroxyl group attached to the beta-position are activated [].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. Short Name:  Thr-tRNA-ligase_IIa
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0 Child Features

6 Contains

DB identifier Type Name
IPR004154 Domain Anticodon-binding
IPR006195 Domain Aminoacyl-tRNA synthetase, class II
IPR002314 Domain Aminoacyl-tRNA synthetase, class II (G/ P/ S/T)
IPR012947 Domain Threonyl/alanyl tRNA synthetase, SAD
IPR018163 Domain Threonyl/alanyl tRNA synthetase, class II-like, putative editing domain
IPR015011 Domain Threonyl-tRNA synthetase, editing domain, archaea

3 Cross Referencess

Identifier
PR01047
TIGR00418
MF_00184

0 Found In

4 GO Annotations

GO Term Gene Name
GO:0004829 IPR002320
GO:0005524 IPR002320
GO:0006435 IPR002320
GO:0005737 IPR002320

4 Ontology Annotations

GO Term Gene Name
GO:0004829 IPR002320
GO:0005524 IPR002320
GO:0006435 IPR002320
GO:0005737 IPR002320

0 Parent Features

3256 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
442211 D8RRP1 PAC:15409199 Selaginella moellendorffii 795  
447798 D8T2D3 PAC:15405452 Selaginella moellendorffii 564  
130418 D8T2D2 PAC:15421699 Selaginella moellendorffii 647  
evm.model.supercontig_136.10 PAC:16408298 Carica papaya 318  
evm.model.supercontig_258.12 PAC:16415002 Carica papaya 282  
29883.m002043 B9S4M4 PAC:16812130 Ricinus communis 691  
29608.m000203 B9T183 PAC:16803593 Ricinus communis 658  
Cucsa.100510.1 A0A0A0K179 PAC:16958577 Cucumis sativus 672  
Cucsa.100510.2 PAC:16958578 Cucumis sativus 530  
Cucsa.100510.3 PAC:16958579 Cucumis sativus 484  
Cucsa.183420.3 PAC:16967523 Cucumis sativus 272  
Cucsa.183420.4 PAC:16967524 Cucumis sativus 268  
Cucsa.183420.2 PAC:16967522 Cucumis sativus 305  
orange1.1g046808m PAC:18126348 Citrus sinensis 653  
orange1.1g006680m PAC:18101473 Citrus sinensis 635  
orange1.1g007503m PAC:18101474 Citrus sinensis 601  
orange1.1g008152m PAC:18101475 Citrus sinensis 576  
AT5G26830.1 O04630 PAC:19667477 Arabidopsis thaliana 709  
AT1G17960.1 Q8GZ45 PAC:19654166 Arabidopsis thaliana 458  
AT2G04842.1 F4IFC5 PAC:19638325 Arabidopsis thaliana 650  
Thhalv10002438m V4MX54 PAC:20196361 Eutrema salsugineum 651  
Thhalv10003725m V4KXR4 PAC:20199501 Eutrema salsugineum 712  
Ciclev10018290m V4U4U1 PAC:20815026 Citrus clementina 733  
Ciclev10030825m PAC:20802458 Citrus clementina 718  
Lus10005351 PAC:23148512 Linum usitatissimum 686  
Lus10030843 PAC:23155395 Linum usitatissimum 270  
Lus10012360 PAC:23176799 Linum usitatissimum 676  
Lus10021402 PAC:23179155 Linum usitatissimum 686  
Lus10030645 PAC:23140538 Linum usitatissimum 1001  
Lus10030644 PAC:23140729 Linum usitatissimum 130  

8 Publications

First Author Title Year Journal Volume Pages PubMed ID
            8364025
            8274143
            1852601
            2053131
            10673435
            2203971
            10319817
            10881191