An orthogonal ribosome-tRNA pair via engineering of the peptidyl transferase center.

The Watson-Crick base pairs between the 3'-terminal end of tRNAs and ribosomal RNA in the peptidyl transferase center are universally conserved. Here, we report that the introduction of compensatory mutations to Escherichia coli RNAs in this site leads to an orthogonal system independent of the wild-type counterpart, as demonstrated via the production of two peptide sequences from a single mRNA. This work thus identifies a new way to reprogram the genetic code.