key term - Aminoacyl-tRNA synthetase

Definition

Aminoacyl-tRNA synthetase is an essential enzyme that catalyzes the attachment of an amino acid to its corresponding transfer RNA (tRNA), forming aminoacyl-tRNA. This process is crucial for translating the genetic code into proteins, as it ensures that the correct amino acids are incorporated into growing polypeptide chains during protein synthesis.

5 Must Know Facts For Your Next Test

1. There are 20 different aminoacyl-tRNA synthetases, one for each of the standard amino acids, which ensures specificity during protein synthesis.
2. Each aminoacyl-tRNA synthetase recognizes its specific tRNA and corresponding amino acid, maintaining the fidelity of protein translation.
3. The reaction catalyzed by aminoacyl-tRNA synthetase involves the activation of an amino acid using ATP, forming an aminoacyl-AMP intermediate before transferring the amino acid to tRNA.
4. Errors in charging tRNAs can lead to incorporation of incorrect amino acids into proteins, potentially resulting in malfunctioning or nonfunctional proteins.
5. The accuracy of aminoacyl-tRNA synthetases is critical for cellular function, as even minor errors in protein synthesis can have significant consequences for cell health and function.

Review Questions

• How does aminoacyl-tRNA synthetase contribute to the accuracy of protein synthesis?
  • Aminoacyl-tRNA synthetase contributes to the accuracy of protein synthesis by ensuring that each tRNA molecule is charged with the correct amino acid that corresponds to its anticodon. Each enzyme has a specific affinity for its respective tRNA and amino acid, allowing it to accurately match them. This selective attachment helps prevent errors during translation, which could lead to dysfunctional proteins.
• Discuss the potential consequences if an aminoacyl-tRNA synthetase mischarges a tRNA with an incorrect amino acid.
  • If an aminoacyl-tRNA synthetase mischarges a tRNA with an incorrect amino acid, this could lead to the incorporation of that wrong amino acid into a growing polypeptide chain during translation. Such errors may result in proteins that do not fold properly or perform their intended functions, potentially leading to cellular dysfunction or disease. This underscores the importance of fidelity in the aminoacylation process to maintain proper cellular functions.
• Evaluate the role of aminoacyl-tRNA synthetases in evolutionary biology regarding protein diversity and adaptation.
  • Aminoacyl-tRNA synthetases play a crucial role in evolutionary biology by facilitating the accurate translation of genetic information into diverse proteins, which are essential for adaptation and survival. Variations in these enzymes among different organisms can lead to differences in protein synthesis efficiency and accuracy, influencing evolutionary trajectories. As organisms adapt to their environments, changes in the specificity and activity of these enzymes may contribute to the development of new metabolic pathways or functional capabilities, thus shaping evolutionary outcomes.

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.

amino acid:

Amino acids are organic compounds that serve as the building blocks of proteins, each containing an amino group, a carboxyl group, and a unique side chain.

ribosome:

The ribosome is a cellular structure that facilitates the translation of mRNA into proteins by serving as the site for protein synthesis and bringing together mRNA and tRNA.