Incorporation of fluorescently labeled nonnatural amino acids into proteins in an E. coli in vitro translation system

Various nonnatural amino acids has been incorporated into proteins by using four-base codons in an E. coli in vitro translation system. Here, design and synthesis of novel fluorescently labeled nonnatural amino acids and their incorporation into proteins were investigated. Transfer RNAs that contained a CCCG anticodon and were aminoacylated with BODIPY FL-labeled amino acids were prepared by a chemical aminoacylation method, and added to an in vitro translation system in the presence of a streptavidin mRNA containing a CGGG codon. SDS-PAGE and Western blot analysis of the synthesized proteins indicate that BODIPY FL-labeled aminophenylalanine derivatives are efficiently incorporated into proteins through the four-base codon decoding.