title: Selective incorporation of 5-hydroxytryptophan into proteins in mammalian cells.
abstract: An orthogonal tryptophanyl-transfer RNA (tRNA) synthetase (TrpRS)-mutant opal suppressor tRNA(Trp) (mutRNA(UCA)(Trp)) pair was generated for use in mammalian cells. The anticodon loop of the Bacillus subtilis tRNA(Trp) was mutated to UCA, three positions in the D arm were mutated to generate an internal promoter sequence, and the mutRNA(UCA)(Trp) gene was inserted between the 5' and 3' flanking sequences of the tRNA(Trp-1) gene from Arabidopsis to enhance its expression in mammalian cells. In vitro aminoacylation assays and in vivo opal suppression assays showed that B. subtilis TrpRS (BsTrpRS) charges only the cognate mutRNA(UCA)(Trp) and no endogenous mammalian tRNAs. Similarly, the mutRNA(UCA)(Trp) is specifically charged by B. subtilis TrpRS and not by endogenous synthetases in mammalian cells. Site-directed mutagenesis was then used to alter the specificity of BsTrpRS to uniquely charge 5-hydoxy-l-tryptophan. The resulting mutant BsTrpRS-mutRNA(UCA)(Trp) pair allows the efficient and selective incorporation of 5-hydroxy-l-tryptophan into mammalian proteins in response to the codon, TGA. This amino acid can be used as a fluorescence probe and also undergoes electrochemical oxidation in situ to generate an efficient protein crosslinking.
authors.affiliation: Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Lital
authors.initials: L
authors.lastname: Alfonta
authors.forename: Feng
authors.initials: F
authors.lastname: Tian
authors.forename: Badry
authors.initials: B
authors.lastname: Bursulaya
authors.forename: Sean
authors.initials: S
authors.lastname: Uryu
authors.forename: David S
authors.initials: DS
authors.lastname: King
authors.forename: Peter G
authors.initials: PG
authors.lastname: Schultz
mesh_terms: D006916:5-Hydroxytryptophan / Q000378:metabolism*; D000926:Anticodon / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics; D001483:Base Sequence; D002460:Cell Line; D003062:Codon / Q000235:genetics; D003432:Cross-Linking Reagents / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009690:Nucleic Acid Conformation; D012364:RNA, Transfer, Trp / Q000235:genetics / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013489:Suppression, Genetic; D014162:Transfection; D014369:Tryptophan-tRNA Ligase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000926:Anticodon; D003062:Codon; D003432:Cross-Linking Reagents; D012364:RNA, Transfer, Trp; D006916:5-Hydroxytryptophan; D014369:Tryptophan-tRNA Ligase