Aminoacyl tRNA synthetase
An aminoacyl-tRNA synthetase (aaRS or ARS), also called tRNA-ligase, is an enzyme that attaches the appropriate amino acid onto its corresponding tRNA. It does so by catalyzing the transesterification of a specific cognate amino acid or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA. In humans, the 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases, one for each amino acid of the genetic code.
| Anticodon-binding domain of tRNA | |||||||||
|---|---|---|---|---|---|---|---|---|---|
leucyl-tRNA synthetase from Thermus thermophilus complexed with a post-transfer editing substrate analogue | |||||||||
| Identifiers | |||||||||
| Symbol | Anticodon_2 | ||||||||
| Pfam | PF08264 | ||||||||
| InterPro | IPR013155 | ||||||||
| SCOP2 | 1ivs / SCOPe / SUPFAM | ||||||||
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| DALR anticodon binding domain 1 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Thermus thermophilus arginyl-trna synthetase | |||||||||
| Identifiers | |||||||||
| Symbol | DALR_1 | ||||||||
| Pfam | PF05746 | ||||||||
| Pfam clan | CL0258 | ||||||||
| InterPro | IPR008909 | ||||||||
| SCOP2 | 1bs2 / SCOPe / SUPFAM | ||||||||
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| DALR anticodon binding domain 2 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
crystal structure of cysteinyl-tRNA synthetase binary complex with tRNACys | |||||||||
| Identifiers | |||||||||
| Symbol | DALR_2 | ||||||||
| Pfam | PF09190 | ||||||||
| Pfam clan | CL0258 | ||||||||
| InterPro | IPR015273 | ||||||||
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This is sometimes called "charging" or "loading" the tRNA with an amino acid. Once the tRNA is charged, a ribosome can transfer the amino acid from the tRNA onto a growing peptide, according to the genetic code. Aminoacyl tRNA therefore plays an important role in RNA translation, the expression of genes to create proteins.