Aminoacyl-tRNA synthetase

Definition

Aminoacyl-tRNA synthetase is an enzyme that plays a crucial role in protein synthesis by attaching the appropriate amino acid to its corresponding tRNA molecule, ensuring that the genetic code is accurately translated into proteins. This enzyme is essential for interpreting the genetic code, as it facilitates the correct pairing of amino acids with their codons during translation, thus linking the genetic information carried by mRNA to the polypeptide chain being formed on the ribosome.

5 Must Know Facts For Your Next Test

1. Aminoacyl-tRNA synthetase is highly specific, with each enzyme recognizing and attaching only one type of amino acid to its corresponding tRNA molecule.
2. There are 20 different aminoacyl-tRNA synthetases, one for each standard amino acid, ensuring precise translation of the genetic code.
3. The enzyme utilizes ATP to activate the amino acid before it is transferred to tRNA, forming an aminoacyl-tRNA complex.
4. The accuracy of protein synthesis depends heavily on the correct function of aminoacyl-tRNA synthetase, as mischarging tRNA can lead to the incorporation of incorrect amino acids into proteins.
5. Aminoacyl-tRNA synthetases play a role in the proofreading process, where they can detect and correct errors in amino acid attachment to tRNA.

Review Questions

• How does aminoacyl-tRNA synthetase ensure fidelity in protein synthesis?
  • Aminoacyl-tRNA synthetase ensures fidelity in protein synthesis by specifically recognizing and attaching only the correct amino acid to its corresponding tRNA. This high specificity is crucial because if an incorrect amino acid were attached, it could lead to faulty protein structures and functions. The enzyme uses both the shape of the tRNA and the side chains of amino acids as recognition features to maintain accuracy during this critical step.
• Discuss the role of ATP in the function of aminoacyl-tRNA synthetase during translation.
  • ATP plays a vital role in the function of aminoacyl-tRNA synthetase by providing energy needed to activate the amino acid. When an amino acid binds to the enzyme, ATP is hydrolyzed to AMP and pyrophosphate, which activates the amino acid for attachment to tRNA. This energy investment is essential for forming a stable aminoacyl-tRNA complex that can be accurately delivered to the ribosome for translation.
• Evaluate the implications of malfunctioning aminoacyl-tRNA synthetase on cellular processes and organismal health.
  • Malfunctioning aminoacyl-tRNA synthetase can have severe implications for cellular processes and overall organismal health. If this enzyme incorrectly charges tRNAs with wrong amino acids or fails to charge them at all, it can lead to nonfunctional or dysfunctional proteins being produced. Such errors can contribute to various diseases, including neurodegenerative disorders and metabolic syndromes, highlighting the importance of this enzyme in maintaining proper protein synthesis and cellular function.

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.

Codon: A codon is a sequence of three nucleotides on mRNA that specifies a particular amino acid or signals the termination of protein synthesis.

Ribosome: Ribosomes are cellular structures composed of rRNA and proteins, where translation of mRNA into proteins occurs, facilitating the assembly of amino acids into polypeptide chains.