In this video we have discussed the tRNA Charging or Aminoacylation in Prokaryotes.
This reaction is catalyzed by aminoacyl tRNA synthetases.
An aminoacyl-tRNA synthetase (aaRS or ARS), also called tRNA-ligase, is an enzyme that attaches the appropriate amino acid onto its tRNA. It does so by catalyzing the esterification of a specific cognate amino acid or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA. In humans, the 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases, one for each amino acid of the genetic code.
This is sometimes called "charging" or "loading" the tRNA with the amino acid. Once the tRNA is charged, a ribosome can transfer the amino acid from the tRNA onto a growing peptide, according to the genetic code. Aminoacyl tRNA therefore plays an important role in RNA translation, the expression of genes to create proteins.
The mechanism can be summarized in the following reaction series:
Amino Acid + ATP → Aminoacyl-AMP + PPi
Aminoacyl-AMP + tRNA → Aminoacyl-tRNA + AMP
Summing the reactions, the highly exergonic overall reaction is as follows:
Amino Acid + tRNA + ATP → Aminoacyl-tRNA + AMP + PPi
4 авг 2024
