Beyond the canonical 20 amino acids: expanding the genetic lexicon.
The ability to genetically encode unnatural amino acids beyond the common 20 has allowed unprecedented control over the chemical structures of recombinantly expressed proteins. Orthogonal aminoacyl-tRNA synthetase/tRNA pairs have been used together with nonsense, rare, or 4-bp codons to incorporate >50 unnatural amino acids into proteins in Escherichia coli, Saccharomyces cerevisiae, Pichia pastoris, and mammalian cell lines. This has allowed the expression of proteins containing amino acids with novel side chains, including fluorophores, post-translational modifications, metal ion chelators, photocaged and photocross-linking moieties, uniquely reactive functional groups, and NMR, IR, and x-ray crystallographic probes.
Young
Travis S
TS
Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA.
Schultz
Peter G
PG
D000596:Amino Acids / Q000737:chemistry*; D000818:Animals; D001671:Biochemistry / Q000379:methods*; D002460:Cell Line; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D008956:Models, Chemical; D008957:Models, Genetic; D010843:Pichia / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D012343:RNA, Transfer / Q000378:metabolism; D012441:Saccharomyces cerevisiae
D000596:Amino Acids; D012343:RNA, Transfer