Aminoacyl tRNA Synthetase

What are Aminoacyl tRNA Synthetase?

Aminoacyl-tRNA synthetase(AARS), also known as tRNA ligases, are a family of enzymes that are responsible for adding amino acids to their cognate tRNA molecules. There are 21 AARS in the human body, one enzyme for each amino acid, with the exception of lysine, for which there are two AARS. In addition to these 21 AARS for protein amino acids, there are also AARS for non-protein amino acids, such as pyrrole lysyl tRNA synthetase and phosphoserine tRNA synthetase. Each tRNA has a specific AARS to activate it. When tRNA is aminoacylated, the ribosome can transfer amino acids from the tRNA to the peptide being synthesized according to the genetic code. Thus, the process of aminoacyl tRNA plays an important role in RNA translation and gene expression of proteins.

The aaRS·tRNA complex (PDB:1f7u) and the architecture of its active site.Figure 1. The aaRS·tRNA complex (PDB:1f7u) and the architecture of its active site.(K, Florian.;et al. 2020)

Aminoacyl tRNA Synthetase Mechanism

The process of AARS aminoacylation occurs in two steps:

  • Step 1 - AARS binds ATP and the appropriate amino acid (or its precursor) to form an aminoacyl adenylate, releasing inorganic pyrophosphate (PPi).
  • Step 2 - The adenylate-AARS complex binds the D arm of the appropriate tRNA molecule and the amino acid is transferred from the aa-AMP to the 2'- or 3'-OH of the last tRNA nucleotide (A76) at the 3'-end.

Amino acid activation by aminoacyl tRNA synthetase and attachment to tRNA. - BOC SciencesFigure 2. Amino acid activation by aminoacyl tRNA synthetase and attachment to tRNA.

Aminoacyl-tRNA synthetases are highly accurate, and some synthetases also mediate editing reactions to hydrolyze away incorrect tRNA additions to ensure high fidelity and specificity of the tRNA aminoacyl process.

Aminoacyl tRNA Synthetase Classes

AARS enzymes are divided into two main classes, including class I and class II.

Class I AARS has two highly conserved sequence motifs, HIGH and KMSKS, which are aminoacylated at the 2'-OH of the terminal adenosine nucleotide of the tRNA. Class I enzymes are generally monomeric or dimeric.

Class II AARS has multiple highly conserved sequence motifs that are amidated at the 3'-OH of the terminal adenosine of the tRNA. Class II enzymes are usually dimers or tetramers.

Aminoacyl tRNA Synthetase from BOC Sciences

Aminoacyl tRNA synthetases play important roles in RNA translation, gene expression, cellular metabolism, signaling, and disease mechanisms. BOC Sciences offers a wide range of aminoacyl tRNA synthetases with different structures and functions to aid you in your research on potential drug targets for the treatment of various diseases.

  • AARSD1
  • DARS
  • LFARS2
  • KARS
  • RARS
  • TARS
  • WARS2
  • ART1
  • DARS2
  • NARS2
  • SARS
  • TYW3
  • YARS
  • CARS
  • DUS1
  • HARS
  • QARS
  • SARS2
  • WARS
  • YARS2

Applications of BOC Sciences' Aminoacyl tRNA Synthetase

  • To develop in vitro protein synthesis systems for in vitro recombinant protein synthesis and protein-protein interaction studies.
  • To integrate synthetic unnatural or rare amino acids (e.g., photoreactive, metal-chelating, xenon chelating, cross-linking, spin-resonating, fluorescent, biotinylated and reactive group-bearing amino acids) into any desired position in any protein of interest using specific aminoacyl tRNA synthetases to alter the function and activity of target proteins.
  • To advance the study and development of inhibitors for diseases associated with mutations in aminoacyl tRNA synthetase, such as neurodegenerative diseases, cancers, metabolic diseases, autoimmune diseases, etc.

For more detail about our aminoacyl tRNA synthetases, please feel free to contact us.


  1. K, Florian.; et al. The Structural Basis of the Genetic Code: Amino Acid Recognition by Aminoacyl-Trna Synthetases. Scientific Reports. 2020, 10: 12647.
* Only for research. Not suitable for any diagnostic or therapeutic use.
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