An amino acid becomes attached to the appropriate tRNA in a twostep reaction

amino acid). This reaction takes place in two steps (Figure 15.18). To identify the resulting aminoacylated tRNA, we write the three-letter abbreviation for the amino acid in front of the tRNA; for example, the amino acid alanine (Ala) attaches to its tRNA (tRNAAIa), giving rise to its aminoacyl-tRNA (Ala-tRNAAla).

Errors in tRNA charging are rare; they occur in only about 1 in 10,000 to 1 in 100,000 reactions. This fidelity is due to the presence of proofreading activity in the synthetases, which detects and removes incorrectly paired amino acids from the tRNAs. __

0 0

Post a comment