Aminoacyl-trna synthetase

Definition

Aminoacyl-tRNA synthetase is an enzyme that catalyzes the attachment of a specific amino acid to its corresponding transfer RNA (tRNA) molecule, forming an aminoacyl-tRNA complex. This reaction is crucial for the accuracy of protein synthesis, as it ensures that the correct amino acid is incorporated into the growing polypeptide chain during translation. By linking the genetic code to the correct amino acids, this enzyme plays a vital role in bridging the information encoded in DNA and RNA with the proteins that perform most cellular functions.

5 Must Know Facts For Your Next Test

1. There are 20 different aminoacyl-tRNA synthetases, each specific to one amino acid and its corresponding tRNAs, ensuring fidelity in protein synthesis.
2. The enzyme works by first activating the amino acid with ATP, creating an aminoacyl-adenylate intermediate before transferring the amino acid to tRNA.
3. Aminoacyl-tRNA synthetases play a proofreading role by checking if the correct amino acid is attached to the right tRNA, minimizing errors in translation.
4. The reaction catalyzed by this enzyme occurs in two steps: formation of aminoacyl-AMP and then transfer to tRNA, which ultimately forms aminoacyl-tRNA.
5. Mutations in genes coding for these enzymes can lead to various diseases, as errors in tRNA charging can disrupt normal protein synthesis.

Review Questions

• How does aminoacyl-tRNA synthetase ensure accuracy during protein synthesis?
  • Aminoacyl-tRNA synthetase ensures accuracy by specifically recognizing and binding both the correct amino acid and its corresponding tRNA. This enzyme first activates the amino acid with ATP, forming an intermediate before transferring it to tRNA. Additionally, many synthetases possess proofreading capabilities to double-check their work, minimizing the chances of incorporating incorrect amino acids into proteins during translation.
• Discuss the implications of mutations in genes coding for aminoacyl-tRNA synthetases on cellular function.
  • Mutations in genes coding for aminoacyl-tRNA synthetases can have significant consequences on cellular function due to their critical role in protein synthesis. If an enzyme mischarges tRNA with the wrong amino acid, it can lead to dysfunctional proteins that may affect cellular processes or contribute to diseases. Such errors can disrupt normal cellular activities and even lead to conditions such as neurodegenerative disorders or cancers, highlighting the importance of these enzymes in maintaining cellular integrity.
• Evaluate the role of aminoacyl-tRNA synthetases in linking the genetic code to functional proteins within the context of molecular biology.
  • Aminoacyl-tRNA synthetases are essential for linking the genetic code found in mRNA to functional proteins by ensuring that each codon is matched with the appropriate amino acid during translation. This process embodies a key aspect of the central dogma of molecular biology, where information flows from DNA to RNA and finally to protein. Their precise function not only facilitates accurate protein synthesis but also emphasizes how genetic information translates into biological activity, ultimately shaping cellular structure and function.

Related terms

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

ribosome: A ribosome is a cellular structure composed of ribosomal RNA and proteins that serves as the site of protein synthesis, where mRNA is translated into polypeptides.

codon: A codon is a sequence of three nucleotides on an mRNA strand that corresponds to a specific amino acid or a stop signal during protein synthesis.