Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

ChainsTypeFamily Name Domain Identifier Family IdentifierProvenance Source (Version)
ASCOP2 FamilyClass I aminoacyl-tRNA synthetases (RS) catalytic domain8031825 4003807 SCOP2 (2022-06-29)
ASCOP2 FamilyAnticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetases8024765 4000856 SCOP2 (2022-06-29)
ASCOP2 SuperfamilyNucleotidylyl transferase8044203 3001541 SCOP2 (2022-06-29)
ASCOP2 SuperfamilyAnticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetases8037144 3001786 SCOP2 (2022-06-29)
ASCOP2B SuperfamilyValRS/IleRS/LeuRS editing domain8041728 3001115 SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

ChainsFamily NameDomain Identifier ArchitecturePossible HomologyHomologyTopologyFamilyProvenance Source (Version)
AtRNA-synt_1_2nde1ileA4 A: beta barrelsX: cradle loop barrelH: RIFT-relatedT: acid proteaseF: tRNA-synt_1_2ndECOD (1.6)
AAnticodon_1,tRNA-synt_1_1ste1ileA5 A: alpha bundlesX: Anticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetases (From Topology)H: Anticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetases (From Topology)T: Anticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetasesF: Anticodon_1,tRNA-synt_1_1stECOD (1.6)
AtRNA-synt_1_1ste1ileA3 A: a/b three-layered sandwichesX: HUP domain-likeH: HUP domains (From Topology)T: HUP domainsF: tRNA-synt_1_1stECOD (1.6)
AileS_1ste1ileA2 A: few secondary structure elementsX: Rubredoxin-likeH: Rubredoxin-relatedT: Rubredoxin-relatedF: ileS_1stECOD (1.6)
AtRNA-synt_1_3rde1ileA1 A: few secondary structure elementsX: Rubredoxin-likeH: Rubredoxin-relatedT: Rubredoxin-relatedF: tRNA-synt_1_3rdECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

ChainDomainClassArchitectureTopologyHomologyProvenance Source (Version)
A3.40.50.620 Alpha Beta 3-Layer(aba) Sandwich Rossmann fold HUPsCATH (4.3.0)
A3.90.740.10 Alpha Beta Alpha-Beta Complex Isoleucyl-tRNA Synthetase domain 2CATH (4.3.0)
A1.10.730.10 Mainly Alpha Orthogonal Bundle Isoleucyl-tRNA Synthetase Domain 1CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

ChainsAccessionNameDescriptionCommentsSource
PF08264Anticodon-binding domain of tRNA ligase (Anticodon_1)Anticodon-binding domain of tRNA ligaseThis domain is found mainly hydrophobic tRNA synthetases. The domain binds to the anticodon of the tRNA ligase.Domain
PF00133tRNA synthetases class I (I, L, M and V) (tRNA-synt_1)tRNA synthetases class I (I, L, M and V)Other tRNA synthetase sub-families are too dissimilar to be included.Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

ChainsPolymerMolecular FunctionBiological ProcessCellular Component
ISOLEUCYL-TRNA SYNTHETASE

Structure Motif Annotation: Mechanism and Catalytic Site Atlas M-CSA Database Homepage

ChainsEnzyme NameDescriptionCatalytic Residues
isoleucine-tRNA ligase (type 2)  M-CSA #309

Isoleucine-tRNA ligase (also known as Isoleucyl-tRNA synthetase) is an alpha monomer that belongs to class Ia tRNA synthetases. It activates not only the cognate substrate L-isoleucine but also the structurally similar L-valine in the first, amino-acylation step. In a second, \"editing\" step, the synthetase itself rapidly hydrolyses only the valylated products. For this two-step substrate selection, a \"double-sieve\" mechanism has been proposed to explain the high substrate fidelity and low copy error of the tRNA synthetase.

Escherichia coli isoleucyl-tRNA synthetasehas been shown to contain two enzyme-bound zinc atoms per polypeptide chain. The N-terminal zinc ion may play a structural role. Although the two zinc domains are always conserved, the zinc ligands are not, so that there can be both zinc atoms, no zinc atoms or only one of the two. The C-terminal zinc ion is essential (for function in vivo). It plays an important roles in aminoacylation of tRNA(Ile) [PMID:7488160, PMID:8672449].

Defined by 7 residues: PRO:A-46ASP:A-85TRP:A-518GLN:A-554TRP:A-558LYS:A-591LYS:A-594
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