d-Tyrosyl-tRNA Deacylase: A New Function

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• d-Aminoacyl-tRNA deacylase (DTD) is crucial for maintaining protein homochirality by removing aberrant d-amino acids from tRNAs.
• The enzyme's role has been primarily associated with 'chiral proofreading' in protein synthesis.

Purpose of the Study:

• To investigate the full enzymatic repertoire of d-aminoacyl-tRNA deacylase (DTD).
• To determine if DTD's function extends beyond the hydrolysis of canonical d-amino acids.

Main Methods:

• Biochemical assays were used to test the substrate specificity of DTD.
• In vitro experiments were conducted to assess the deacylation of glycine-tRNA Ala by DTD.

Main Results:

• d-Aminoacyl-tRNA deacylase (DTD) was found to hydrolyze not only d-amino acids but also glycine erroneously coupled to tRNA Ala.
• This finding demonstrates a novel function for DTD beyond its established role in chiral proofreading.

Conclusions:

• The function of d-aminoacyl-tRNA deacylase (DTD) is broader than previously understood, encompassing the removal of specific non-chiral amino acid misacylations.
• DTD plays a significant role in ensuring the fidelity of protein synthesis by preventing the incorporation of incorrect amino acids, including glycine on tRNA Ala.