title: Synthesis and structural characterization of bioactive peptide conjugates using thioether linkage approaches.
abstract: Applications of cysteine-insertion and thioether linkage approaches to the preparation of a number of bioactive peptide conjugates are reported. Peptides containing epitopes from (i) herpes simplex virus type 1 glycoprotein D, (ii) a specific N-terminal beta-amyloid epitope recognized by therapeutically active antibodies, and (iii) a GnRH-III peptide from sea lamprey with antitumour activity, were elongated with Cys residues and attached to a chloroacetylated tetratuftsin derivative carrier via a thioether linkage either directly, or by insertion of a spacer. The structures and molecular homogeneity of all the peptide conjugates were ascertained by HPLC, MALDI and electrospray mass spectrometry. The use of a spacer such as an oligoglycine or GFLG-tetrapeptide gave an increased yield in the conjugation reaction and enhanced reaction rates. In the formation of cysteinyl-thioether linkages, it was found that the position of flanking Cys residues markedly influenced the conjugation reaction and the formation of intermolecular epitope disulfide-dimers. C-terminal Cys residues gave thioether conjugates with significantly diminished epitope-dimerization, while Cys at the N-terminal caused rapid disulfide-dimerization, thereby preventing efficient conjugation.
authors.affiliation: Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös L. University, Budapest, Hungary. mezo@szerves.chem.elte.hu
authors.forename: Gábor
authors.initials: G
authors.lastname: Mezö
authors.forename: Marilena
authors.initials: M
authors.lastname: Manea
authors.forename: Annamária
authors.initials: A
authors.lastname: Jakab
authors.forename: Bence
authors.initials: B
authors.lastname: Kapuvári
authors.forename: Szilvia
authors.initials: S
authors.lastname: Bösze
authors.forename: Gitta
authors.initials: G
authors.lastname: Schlosser
authors.forename: Michael
authors.initials: M
authors.lastname: Przybylski
authors.forename: Ferenc
authors.initials: F
authors.lastname: Hudecz
mesh_terms: D000085:Acetates; D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000737:chemistry; D000939:Epitopes / Q000737:chemistry*; D007987:Gonadotropin-Releasing Hormone / Q000737:chemistry; D009842:Oligopeptides / Q000138:chemical synthesis; D010084:Oxidation-Reduction; D010455:Peptides / Q000138:chemical synthesis*; D013440:Sulfides / Q000138:chemical synthesis*; D014405:Tuftsin / Q000737:chemistry
chemical_list: D000085:Acetates; D000939:Epitopes; D009842:Oligopeptides; D010455:Peptides; D013440:Sulfides; D007987:Gonadotropin-Releasing Hormone; C006972:chloroacetic acid; D003545:Cysteine; D014405:Tuftsin