title: Simultaneous multiple synthesis and selective conjugation of cyclized peptides derived from a surface loop of a meningococcal class 1 outer membrane protein.
abstract: Starting from the alpha-(2,4-dimethoxybenzyl) ester of N-(9-fluorenylmethoxycarbonyl)aspartic acid [Fmoc-Asp-ODmb], side-chain-protected resin-bound Fmoc-peptides containing an N epsilon-1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl lysyl [Lys(Dde)] residue were prepared. The C-terminal dimethoxybenzyl esters of aspartic acid were removed with 1% trifluoroacetic acid and 10% anisole in dichloromethane, followed by Fmoc-cleavage in the usual manner. The resin-bound peptides were then cyclized using 1-benzotriazolyloxy-tris-[N-pyrrolidino]phosphonium hexafluorophosphate (PyBOP) in the presence of N-methylmorpholine. The (dimethyldioxocyclohexylidene)ethyl groups of lysine were removed with 1% hydrazine hydrate in N,N-dimethylacetamide, and the liberated side-chain amino functions were modified by reaction with pentafluorophenyl S-acetylmercaptoacetate (SAMA-OPfp). Finally, the peptides were side-chain deprotected, with exception of the Lys(SAMA) residue, and cleaved from the solid support with trifluoroacetic acid/anisole/water, 95/2.5/2.5. Cyclic peptides comprising 7-14 amino acid residues were obtained employing this procedure. As a model conjugation, cyclo[Thr-Asn-Asn-Asn-Leu-Lys(SAMA)-Thr-Lys-Asp] was coupled with bromoacetamide. The same peptide was also coupled with a bromoacetylpeptide to give a well defined peptide/peptide conjugate. All peptides were conjugated to bromoacetylated tetanus toxoid for immunization purposes.
authors.affiliation: RIVM (National Institute of Public Health and Environmental Protection), Uhit for Bacterial Vaccine Development, Bilthoven, The Netherlands.
authors.forename: H F
authors.initials: HF
authors.lastname: Brugghe
authors.forename: H A
authors.initials: HA
authors.lastname: Timmermans
authors.forename: L M
authors.initials: LM
authors.lastname: Van Unen
authors.forename: G J
authors.initials: GJ
authors.lastname: Ten Hove
authors.forename: G
authors.initials: G
authors.lastname: Van de Werken
authors.forename: J T
authors.initials: JT
authors.lastname: Poolman
authors.forename: P
authors.initials: P
authors.lastname: Hoogerhout
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000138:chemical synthesis*; D000922:Immunotoxins / Q000737:chemistry; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis; D010456:Peptides, Cyclic; D013745:Tetanus Toxoid / Q000737:chemistry
chemical_list: D001425:Bacterial Outer Membrane Proteins; D000922:Immunotoxins; D010456:Peptides, Cyclic; D013745:Tetanus Toxoid