title: In vitro selection for sense codon suppression.
abstract: The universal genetic code links the 20 naturally occurring amino acids to the 61 sense codons. Previously, the UAG amber stop codon (a nonsense codon) has been used as a blank in the code to insert natural and unnatural amino acids via nonsense suppression. We have developed a selection methodology to investigate whether the unnatural amino acid biocytin could be incorporated into an mRNA display library at sense codons. In these experiments we probed a single randomized NNN codon with a library of 16 orthogonal, biocytin-acylated tRNAs. In vitro selection for efficient incorporation of the unnatural amino acid resulted in templates containing the GUA codon at the randomized position. This sense suppression occurs via Watson-Crick pairing with similar efficiency to UAG-mediated nonsense suppression. These experiments suggest that sense codon suppression is a viable means to expand the chemical and functional diversity of the genetic code.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Frankel
authors.forename: Richard W
authors.initials: RW
authors.lastname: Roberts
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003062:Codon / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D005815:Genetic Code; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D016372:RNA, Antisense / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D013698:Templates, Genetic
chemical_list: D003062:Codon; D018076:DNA, Complementary; D009838:Oligodeoxyribonucleotides; D016372:RNA, Antisense; D012333:RNA, Messenger; D012343:RNA, Transfer