Aminoacyl-trna synthetase

Definition

Aminoacyl-tRNA synthetase is an enzyme that plays a crucial role in the translation process by attaching the appropriate amino acid to its corresponding transfer RNA (tRNA) molecule. This attachment, known as aminoacylation, is essential for ensuring that the genetic code is accurately translated into proteins. Each of the 20 different aminoacyl-tRNA synthetases is specific to a particular amino acid and its compatible tRNA, contributing to the fidelity of protein synthesis.

5 Must Know Facts For Your Next Test

1. Aminoacyl-tRNA synthetases are responsible for ensuring the accuracy of translation by preventing misincorporation of amino acids into proteins.
2. There are 20 different aminoacyl-tRNA synthetases, each tailored for one of the 20 standard amino acids and its corresponding tRNAs.
3. The enzyme recognizes both the amino acid and its specific tRNA through unique structural features, which is crucial for the fidelity of protein synthesis.
4. Aminoacylation involves a two-step reaction: first, the enzyme activates the amino acid with ATP, forming an aminoacyl-AMP intermediate, then transferring the amino acid to the tRNA.
5. Defects in aminoacyl-tRNA synthetases can lead to diseases due to incorrect protein synthesis, highlighting their importance in cellular function.

Review Questions

• How does aminoacyl-tRNA synthetase contribute to the accuracy of protein synthesis?
  • Aminoacyl-tRNA synthetase contributes to protein synthesis accuracy by specifically pairing each amino acid with its corresponding tRNA. By recognizing unique structural features of both the amino acid and tRNA, it minimizes errors during translation. This specificity ensures that the correct amino acid is added according to the mRNA sequence, which is vital for producing functional proteins.
• Describe the mechanism by which aminoacyl-tRNA synthetase activates an amino acid before attaching it to tRNA.
  • The mechanism involves a two-step reaction where the aminoacyl-tRNA synthetase first activates the amino acid by reacting it with ATP to form an aminoacyl-AMP intermediate. In the second step, this activated intermediate is then transferred to the appropriate tRNA, forming an aminoacyl-tRNA complex. This process ensures that the amino acid is correctly charged onto its tRNA before translation begins, playing a critical role in maintaining translational fidelity.
• Evaluate the consequences of errors made by aminoacyl-tRNA synthetases on cellular functions and overall organism health.
  • Errors made by aminoacyl-tRNA synthetases can lead to incorrect incorporation of amino acids during protein synthesis, resulting in dysfunctional or nonfunctional proteins. Such mistakes can disrupt cellular processes and lead to various diseases, including neurodegenerative disorders and metabolic dysfunctions. The impact of these errors highlights the importance of these enzymes not just in individual cells but also on overall organism health and development.

Related terms

tRNA:

Transfer RNA (tRNA) is a type of RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein by carrying specific amino acids to the ribosome during translation.

Genetic Code: The genetic code is the set of rules by which information encoded in genetic material is translated into proteins, consisting of sequences of nucleotides that correspond to specific amino acids.

Translation: Translation is the biological process by which ribosomes synthesize proteins using mRNA as a template, involving the decoding of mRNA codons into the corresponding amino acids.