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A sequence element that tunes E. coli tRNA(GGC)(Ala) to ensure accurate decoding
Mutating the rare A32-U38 nucleotide pair at the top of the anticodon loop of E. coli tRNA(GGC)(Ala) to a more common U32-A38 pair results in a tRNA that performs almost normally on cognate codons but is unusually efficient in reading near-cognate codons. Pre-steady state kinetic measurements on E....
Autores principales: | , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
2009
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2769084/ https://www.ncbi.nlm.nih.gov/pubmed/19305403 http://dx.doi.org/10.1038/nsmb.1581 |
Sumario: | Mutating the rare A32-U38 nucleotide pair at the top of the anticodon loop of E. coli tRNA(GGC)(Ala) to a more common U32-A38 pair results in a tRNA that performs almost normally on cognate codons but is unusually efficient in reading near-cognate codons. Pre-steady state kinetic measurements on E. coli ribosomes show that unlike the wild-type tRNA(GGC)(Ala), the misreading mutant tRNA(GGC)(Ala) shows rapid GTP hydrolysis and no detectable proofreading on near-cognate codons. Similarly, tRNA(GGC)(Ala) mutated to contain C32-G38, a pair which is found in some bacterial tRNA(GGC)(Ala) sequences, was able to decode only the cognate codons, while tRNA(GGC)(Ala) containing a more common C32-A38 pair was able to decode all cognate and near-cognate codons tested. We propose that many of the phylogenetically conserved sequence elements present in each tRNA have evolved to suppress translation of near-cognate codons. |
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