Portal de Periódicos da CAPES

Codon reassignment in the Escherichia coli genetic code

2010; Oxford University Press; Volume: 38; Issue: 22 Linguagem: Inglês

10.1093/nar/gkq707

1362-4962

Tatsuya Mukai, Akiko Hayashi, Fumie Iraha, Aya Sato, K. Ohtake, Shigeyuki Yokoyama, Kensaku Sakamoto,

Bacteriophages and microbial interactions

Most organisms, from Escherichia coli to humans, use the 'universal' genetic code, which have been unchanged or 'frozen' for billions of years. It has been argued that codon reassignment causes mistranslation of genetic information, and must be lethal. In this study, we successfully reassigned the UAG triplet from a stop to a sense codon in the E. coli genome, by eliminating the UAG-recognizing release factor, an essential cellular component, from the bacterium. Only a few genetic modifications of E. coli were needed to circumvent the lethality of codon reassignment; erasing all UAG triplets from the genome was unnecessary. Thus, UAG was assigned unambiguously to a natural or non-natural amino acid, according to the specificity of the UAG-decoding tRNA. The result reveals the unexpected flexibility of the genetic code.