title: Conjugation of epitope peptides with SH group to branched chain polymeric polypeptides via Cys(Npys).
abstract: Since bioconjugates may play an important role as therapeutics in the future, the development of new and effective conjugation strategies is necessary. For the attachment of peptide-like molecules to carriers, there are two main coupling methods involving amide or disulfide bonds. Conjugation through an amide bond can be achieved in several well-defined ways known from peptide chemistry. However, the formation of disulfide bridges between cysteine-containing peptides and carrier molecules still has some problems. In this paper, we describe a novel approach in which the carrier polypeptide is modified by 3-nitro-2-pyridinesulfenyl (Npys)-protected cysteine and this derivative has been applied for conjugation of Cys-containing epitope peptides with poly(L-lysine)-based branched polypeptides. Considering the stability of Npys group in the presence of pentafluorophenol, Boc-Cys(Npys)-OPfp dervivative was selected for introduction to the N-terminal of branches of polypeptides backbone. The branches of the polymers were built up from oligo(DL-alanine) (poly[Lys(DL-Ala(m))], AK) and elongated by an optically active amino acid [poly[Lys(X(i)-DL-Ala(m))], XAK]. We found that the nature of X (Glu, Ser, Thr) has great influence on the incorporation of the protected cysteine residue. Herpes simplex virus and adenovirus epitope peptides were conjugated to Boc-Cys(Npys)-modified polypeptides. Results indicate that the incorporation of epitope peptides depends on the number of Npys group on the polymers as well as on the presence/absence of Boc-protecting group on the Cys residue. This new class of Cys(Npys)-derivatized branched polypeptides is stable for a couple of months and suitable for effective preparation of epitope peptide conjugates possessing increased water solubility.
authors.affiliation: Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös L. University, H-1518, Budapest, Hungary.
authors.forename: G
authors.initials: G
authors.lastname: Mezö
authors.forename: N
authors.initials: N
authors.lastname: Mihala
authors.forename: D
authors.initials: D
authors.lastname: Andreu
authors.forename: F
authors.initials: F
authors.lastname: Hudecz
mesh_terms: D000345:Affinity Labels / Q000737:chemistry*; D000595:Amino Acid Sequence; D003545:Cysteine / Q000031:analogs & derivatives* / Q000737:chemistry; D000939:Epitopes / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D011108:Polymers; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D000345:Affinity Labels; D000939:Epitopes; D010455:Peptides; D011108:Polymers; D013438:Sulfhydryl Compounds; C062289:S-(3-nitro-2-pyridinesulfenyl)cysteine; D003545:Cysteine