Flexizyme as a versatile tRNA acylation catalyst and the application for translation

Here we describe a de novo tRNA acylation system consisting of artificial ribozymes. This system, the flexizyme (Fx) system, allows for the preparation of acyl-tRNAs with almost no limitation on the use of a variety of amino/hydroxy acids and tRNAs. To demonstrate its utility, we have carried out protein synthesis involving site-specific incorporation of nonnatural amino and hydroxy acids via amber or programmed frame-shift suppressions. We have also demonstrated peptide synthesis involving multiple nonnatural amino acids via sense codon suppression. The combination of the Fx system and appropriate cell-free translation is a powerful and flexible tool for mRNA-encoded synthesis of nonnatural polypeptides.