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Further in Vitro Exploration Fails to Support the Allosteric Three-site Model

Ongoing debate in the ribosome field has focused on the role of bound E-site tRNA and the Shine-Dalgarno-anti-Shine-Dalgarno (SD-aSD) interaction on A-site tRNA interactions and the fidelity of tRNA selection. Here we use an in vitro reconstituted Escherichia coli translation system to explore the r...

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Detalles Bibliográficos
Autores principales: Petropoulos, Alexandros D., Green, Rachel
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Biochemistry and Molecular Biology 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3320913/
https://www.ncbi.nlm.nih.gov/pubmed/22378789
http://dx.doi.org/10.1074/jbc.C111.330068
Descripción
Sumario:Ongoing debate in the ribosome field has focused on the role of bound E-site tRNA and the Shine-Dalgarno-anti-Shine-Dalgarno (SD-aSD) interaction on A-site tRNA interactions and the fidelity of tRNA selection. Here we use an in vitro reconstituted Escherichia coli translation system to explore the reported effects of E-site-bound tRNA and SD-aSD interactions on tRNA selection events and find no evidence for allosteric coupling. A large set of experiments exploring the role of the E-site tRNA in miscoding failed to recapitulate the observations of earlier studies (Di Giacco, V., Márquez, V., Qin, Y., Pech, M., Triana-Alonso, F. J., Wilson, D. N., and Nierhaus, K. H. (2008) Proc. Natl. Acad. Sci. U.S.A. 105, 10715–10720 and Geigenmüller, U., and Nierhaus, K. H. (1990) EMBO J. 9, 4527–4533); the frequency of miscoding was unaffected by the presence of E-site-bound cognate tRNA. Moreover, our data provide clear evidence that the reported effects of the SD-aSD interaction on fidelity can be attributed to the binding of ribosomes to an unanticipated site on the mRNA (in the absence of the SD sequence) that provides a cognate pairing codon leading naturally to incorporation of the purported “noncognate” amino acid.