What are the binding sites on ribosomes?

Binding sites on ribosomes refer to RNA sequences found in mRNA to which the ribosomes can bind and initiate translation. These binding sites are oriented 5’ to 3’ E-P-A with respect to the mRNA. Each ribosomal subunit contains 3 binding sites known as the aminoacyl site, the peptidyl site, and the exit site. The aminoacyl or A-site binds to the incoming aminoacyl tRNA, which contains the new amino acid to be added to the polypeptide chain. The peptidyl or P-site holds the tRNA with the growing polypeptide chain. The exit or E-site serves as a threshold, holding the deacylated tRNA before it is released by the ribosome.