The concluding phase of protein synthesis in eukaryotic cells culminates in the release of the newly formed polypeptide chain. This stage, known as termination, is triggered when the ribosome encounters a stop codon (UAA, UAG, or UGA) on the messenger RNA (mRNA). These codons do not code for any amino acid; instead, they signal the end of the coding sequence. Release factors, specifically eRF1 in eukaryotes, recognize these stop codons within the ribosomal A-site.
The successful completion of protein synthesis is vital for cellular function and organismal survival. Errors in the termination process can lead to truncated or extended proteins, potentially disrupting cellular processes and causing disease. Understanding the intricacies of this final stage has broad implications for developing therapies targeting protein synthesis, especially in cases involving genetic mutations or infections. Historically, identifying the specific factors and mechanisms involved in polypeptide release marked a significant advancement in molecular biology, paving the way for a deeper comprehension of gene expression and regulation.
