Trans-translation is a unique process that switches the synthesis of a polypeptide hain encoded by a nonstop mRNA to the mRNA-like domain of tmRNA. The process is used in bacterial cells for rescuing the ribosomes arrested during translation of nonstop mRNA and directing this mRNA and the polypeptide product for degradation. Activity of tmRNA is essential for bacterial survival under adverse conditions, the quality control of translation, and the regulation of certain physiological pathways. The review focuses on recent advances in trans-translation studies. Details of the tmRNA-SmpB interaction and the structures of early ribosomal complexes are characterized, the causes of the appearance of an empty A site in the translating ribosome and possible mechanisms of the stalled ribosome recognition and resume codon determination are discussed, and the proteins degrading nonstop mRNAs and tagged peptides are considered.
- Escherichia coli tmRNA
- protein biosynthesis