Peptide bond formation during translation primarily involves tRNA. When the ribosome assembles around the mRNA, tRNA molecules carrying specific amino acids bind to the ribosome at the A-site using their anticodon to pair with the codons on the mRNA. This occurs when the ribosome facilitates the correct positioning of these tRNAs.
Once the tRNA with the growing polypeptide chain is in the P-site and a new tRNA with an amino acid enters the A-site, the ribosome catalyzes the formation of a peptide bond between the amino acid attached to the tRNA in the A-site and the growing chain on the tRNA in the P-site. This reaction is facilitated by the ribosome but does not involve ribosomal proteins or rRNA directly in the bonding process itself.
In summary, while ribosomes and their associated proteins play a crucial role in translation, the actual peptide bond formation is directly between the components of the tRNA molecules.