[Mechanisms of translation termination].

The review considers the results of both genetical and biochemical studies of translation termination in pro- and eukaryotes. The available information on the components of the protein synthesis machinery, participating in the termination process is summarized. Special attention is paid to the problem of nonsense codon recognition. The possibility of modulation of the process of termination in vivo and in vitro is discussed. All the data considered allow us to propose the hypothesis about the role of the small ribosomal subunit RNA (SrRNA) in translation of natural messengers. Deficiency of AGG and related codone in prokaryotes suggests the possibility of scanning of mRNA's in the coding frame by the 3'-terminus of SrRNA. The context of natural terminators in mRNA's in pro-and eukaryotes reveals that the sequences between 6th and 20th positions both up- and down stream from the nonsense codons are complementary to the 3'-end of SrRNA. Interaction between 3'-terminus of SrRNA and the sequences under consideration is postulated to be important for high efficiency termination of translation.