Using amber and ochre nonsense codons to code two different noncanonical amino acids in one protein gene

Abstract

In Escherichia coli, conventional amber and ochre stop codons can be separately targeted by engineered amber-suppressing Methanocaldococcus jannaschii tyrosyl-tRNA synthetase-tRNAPyl and ochre-suppressing Methanosarcina maezi pyrrolysyl-tRNA synthetase-tRNAPyl pairs for coding two different noncanonical amino acids in one protein gene. Here, we describe the application of this approach to produce a protein with two distinct chemical functionalites which can be selectively labeled with two fluorescent dyes.