RESUMO
Trans-translation, the unique process of the synthesis of the single polipeptide chain from both mRNA and the coding part of tmRNA, is necessary for the cell viability in the changeable environment. The new data concerning the main participants and physiological role of trans-translation and the conditions in which it occurs are summarized. The possible tmRNA function in the translation quality control is also discussed.
Assuntos
Biossíntese de Proteínas/fisiologia , RNA Bacteriano/fisiologia , RNA Mensageiro/fisiologia , Fenômenos Fisiológicos Celulares , Conformação de Ácido Nucleico , Biossíntese de Proteínas/genética , RNA Bacteriano/genética , RNA Bacteriano/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ribossomos/fisiologiaRESUMO
Photoreactive derivatives of tRNAs, containing 6-thioguanosine or diazirine derivative of 5-methyleneaminouridine were compared as probes to modify Escherichia coli ribosomes. The derivatives of tRNA were synthesized by T7 transcription Proportion of the modified nucleotide analogues was optimised to obtain good yield, analogue incorporation and binding to the ribosome. Complexes of the tRNA analogues with the ribosomal P-site were irradiated with mild UV light. Cross-links were analysed by oligonucleotide-directed hydrolysis of rRNA by RNase H and reverse transcription. 6-thioguanosine was proved to be a perspective reagent for cross-linking studies of complex ribonucleoproteides.
