title: Synthesis of peptides and proteins without cysteine residues by native chemical ligation combined with desulfurization.
abstract: The highly chemoselective reaction between unprotected peptides bearing an N-terminal Cys residue and a C-terminal thioester enables the total and semi-synthesis of complex polypeptides. Here we extend the utility of this native chemical ligation approach to non-cysteine containing peptides. Since alanine is a common amino acid in proteins, ligation at this residue would be of great utility. To achieve this goal, a specific alanine residue in the parent protein is replaced with cysteine to facilitate synthesis by native chemical ligation. Following ligation, selective desulfurization of the resulting unprotected polypeptide product with H(2)/metal reagents converts the cysteine residue to alanine. This approach, which provides a general method to prepare alanyl proteins from their cysteinyl forms, can be used to chemically synthesize a variety of polypeptides, as demonstrated by the total chemical syntheses of the cyclic antibiotic microcin J25, the 56-amino acid streptococcal protein G B1 domain, and a variant of the 110-amino acid ribonuclease, barnase.
authors.affiliation: Departments of Cell Biology and Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, CVN-6, La Jolla, California 92037, USA.
authors.forename: L Z
authors.initials: LZ
authors.lastname: Yan
authors.forename: P E
authors.initials: PE
authors.lastname: Dawson
mesh_terms: D000613:Aminobutyrates / Q000737:chemistry; D001426:Bacterial Proteins / Q000138:chemical synthesis; D001430:Bacteriocins / Q000138:chemical synthesis; D003545:Cysteine / Q000737:chemistry*; D008722:Methods; D010455:Peptides / Q000138:chemical synthesis*; D011506:Proteins / Q000138:chemical synthesis*; D012260:Ribonucleases / Q000138:chemical synthesis
chemical_list: D000613:Aminobutyrates; D001426:Bacterial Proteins; D001430:Bacteriocins; C034284:IgG Fc-binding protein, Streptococcus; D010455:Peptides; D011506:Proteins; C020411:microcin; D012260:Ribonucleases; C019760:Bacillus amyloliquefaciens ribonuclease; D003545:Cysteine