Mezö G, Mihala N, Andreu D, Hudecz F
Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös L. University, H-1518, Budapest, Hungary.
Bioconjug Chem. 2000 Jul-Aug;11(4):484-91. doi: 10.1021/bc990116o.
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.
由于生物共轭物未来可能在治疗中发挥重要作用，因此开发新的有效共轭策略是必要的。对于将类肽分子连接到载体上，有两种主要的偶联方法，涉及酰胺键或二硫键。通过酰胺键进行共轭可以通过肽化学中已知的几种明确方法实现。然而，含半胱氨酸的肽与载体分子之间二硫键的形成仍然存在一些问题。在本文中，我们描述了一种新方法，其中载体多肽通过3-硝基-2-吡啶硫基（Npys）保护的半胱氨酸进行修饰，并且该衍生物已用于将含半胱氨酸的表位肽与基于聚（L-赖氨酸）的支链多肽进行共轭。考虑到Npys基团在五氟苯酚存在下的稳定性，选择Boc-Cys（Npys）-OPfp衍生物引入多肽主链分支的N末端。聚合物的分支由寡聚（DL-丙氨酸）（聚[Lys（DL-Ala（m））]，AK）构建，并通过旋光氨基酸[聚[Lys（X（i）-DL-Ala（m））]，XAK]延长。我们发现X（Glu、Ser、Thr）的性质对受保护半胱氨酸残基的掺入有很大影响。单纯疱疹病毒和腺病毒表位肽与Boc-Cys（Npys）修饰的多肽进行了共轭。结果表明，表位肽的掺入取决于聚合物上Npys基团的数量以及半胱氨酸残基上Boc保护基团的存在/不存在。这类新型Cys（Npys）衍生的支链多肽在几个月内是稳定的，适合有效制备具有增加水溶性的表位肽共轭物。
