But Zaher and Green 1 present evidence in this issue (page 161) that, even after peptide-bond formation, the ribosome can detect codon–anticodon mismatches and reacts by bringing the protein’s synthesis to a premature end. At this point, it was thought that the quality-control duties of the ribosome were more or less complete. Once codon–anticodon pairs have formed, the amino acid is chemically linked to the polypeptide chain by a peptide bond. For each one, a specific trinucleotide (a codon) on messenger RNA is paired with a complementary anticodon on a transfer RNA, which at its other end carries the corresponding amino acid.
During translation, the cell’s protein-synthesis factory - the ribosome - carefully monitors the process by which new amino acids are added to a growing polypeptide chain.
For cells to flourish, the genetic code must be translated with great accuracy into the amino acids that proteins are made from.
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