Peptide Bond Formation on the Ribosome: The Role of the 2'-OH Group on the Terminal Adenosine of Peptidyl-tRNA and of the Length of Nascent Peptide Chain

摘要

Ribosome is responsible for precise translation of genetic information into proteins, which are essential in all living organisms. The peptidyl transferase center (PTC) on the large ribosomal subunit catalyzes the synthesis of peptide bonds. Reaction of the α-amino group of aminoacyl-tRNA on the A-site with the carbonyl group of peptidyl-tRNA on the P-site results in transfer of the nascent peptide from peptidyl-tRNA to the aminoacyl-tRNA and elongation of the peptide by one amino acid residue. Structural research on ribosomes together with biochemical studies led to attempts to predict the catalytic mechanism of peptide bond formation.One of the most recent hypotheses by Weinger et al. is the substrate-assisted catalysis in which the 2'-OH group on the 3'-terminal adenosine of peptidyl-tRNA participates in the proton shuttle during the peptide-bond formation (Figure 1).