title: Splicing of unnatural amino acids into proteins: a peptide model study.
abstract: S-Ethyl 2-azidohexanethioate (N3-Hex-SEt), an unnatural amino acid analog of leucine, is coupled with L-cysteine ethyl ester (NH2-Cys-OEt) to obtain N3-Hex-Cys-OEt by native chemical ligation. Coupling of this dipeptide with N-t-butoxycarbonyl-2-diphenylphosphinoethanethioglycinate produces the tripeptide, t-Boc-Gly-Hex-Cys-OEt, in high yield. These reactions suggest an approach for the incorporation of unnatural amino acids into proteins by successive native chemical ligation and Staudinger ligation.
authors.affiliation: University of Toledo, Department of Chemistry, Toledo, Ohio 43606, USA.
authors.forename: Shoufa
authors.initials: S
authors.lastname: Han
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Viola
mesh_terms: D003545:Cysteine / Q000031:analogs & derivatives* / Q000737:chemistry*; D007930:Leucine / Q000031:analogs & derivatives* / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*
chemical_list: D009842:Oligopeptides; D011506:Proteins; C031752:ethyl cysteine; D007930:Leucine; D003545:Cysteine