Aminoacyl-trna synthetase

Definition

Aminoacyl-tRNA synthetase is an essential enzyme that plays a crucial role in protein synthesis by attaching the correct amino acid to its corresponding transfer RNA (tRNA) molecule. This process ensures that the genetic code is accurately translated into proteins during translation, which is vital for cellular function and growth. Each of the 20 amino acids has a specific synthetase that facilitates this attachment, highlighting the precision required in protein synthesis.

5 Must Know Facts For Your Next Test

1. There are 20 distinct aminoacyl-tRNA synthetases, one for each of the standard amino acids, ensuring high fidelity in protein synthesis.
2. Each aminoacyl-tRNA synthetase has a specific active site that recognizes both the amino acid and its corresponding tRNA, allowing for selective attachment.
3. The reaction catalyzed by aminoacyl-tRNA synthetase involves ATP hydrolysis, which provides the energy necessary for forming an aminoacyl-tRNA complex.
4. Errors in aminoacyl-tRNA synthetase activity can lead to mischarging of tRNA, potentially resulting in faulty proteins and cellular dysfunction.
5. In addition to their role in translation, some aminoacyl-tRNA synthetases are involved in signaling pathways and have non-canonical functions in cells.

Review Questions

• How does aminoacyl-tRNA synthetase ensure accuracy in protein synthesis?
  • Aminoacyl-tRNA synthetase ensures accuracy in protein synthesis by specifically recognizing and binding to both a particular amino acid and its corresponding tRNA molecule. Each of the 20 synthetases is designed to attach only its matching amino acid to the correct tRNA, which minimizes errors during translation. This specificity is crucial for maintaining the integrity of proteins being synthesized according to the genetic code.
• Discuss the implications of mischarging tRNA by aminoacyl-tRNA synthetase on cellular function.
  • Mischarging of tRNA by aminoacyl-tRNA synthetase can lead to the incorporation of incorrect amino acids into proteins during translation. This can result in dysfunctional proteins that may lose their biological activity or gain harmful properties, ultimately disrupting normal cellular processes. Such errors can have severe consequences for cell viability, growth, and overall organism health, emphasizing the importance of accuracy in this enzymatic function.
• Evaluate the evolutionary significance of aminoacyl-tRNA synthetases in the context of genetic code expansion.
  • The evolutionary significance of aminoacyl-tRNA synthetases lies in their role in maintaining the fidelity of translation, which is essential for the accurate expression of genetic information. As organisms evolved, so did their genetic codes and associated proteins; therefore, these enzymes adapted to recognize new tRNAs and amino acids as needed. This adaptability has enabled the expansion of genetic coding potential and protein diversity across different species, driving evolutionary innovation and complexity in biological systems.

Related terms

tRNA: Transfer RNA (tRNA) is a type of RNA molecule that serves as the adaptor between the mRNA codon and the corresponding amino acid during protein synthesis.

ribosome: The ribosome is a complex molecular machine made of ribosomal RNA and proteins that facilitates the translation of mRNA into proteins by providing a site for tRNA binding.

translation: Translation is the process of synthesizing proteins from messenger RNA (mRNA) by decoding the mRNA sequence into a chain of amino acids, facilitated by ribosomes and tRNA.