The unique hydroxylproline (Hyp)-linked O-glycan modification is a common process in hydroxyproline-rich glycoproteins (HRGPs). The modification occurs through post-translational hydroxylation at 4-position of proline residues some of which are followed by O-glycosylation at the resulting Hyp which is also found in some secreted peptide hormones such as CLAVATA3 (CLV3) of Arabidopsis thaliana plants. An active mature CLV3 is a tridecapeptide linked to β-L-Araf-(1→2)-β-L-Araf-(1→2)-β-L-Araf at a Hyp residue in the center of the peptide sequence such as Arg-Thr-Val-Hyp-Ser-Gly-Hyp(L-Arafn)-Asp-Pro-Leu-His-His-His (n = 3). We report here the synthesis of the secreted and modified CLV3 glycopeptide with all glycoforms (Araf0–3CLV3) of A. thaliana plants. A highly stereoselective β-arabinofuranosylation of Hyp derivatives as the key step of the synthesis of CLV3 glycopeptide was achieved by NAP ether-mediated IAD, which was effectively applied to the synthesis of oligoarabinosylated hydroxylproline [Hyp(L-Araf1–3)] derivatives. Fmoc-solid phase peptide synthesis was carried out using COMU as the coupling reagent for the introduction of [Hyp(L-Araf0–3)] derivatives as well as further elongation to the CLV3 glycopeptides.
独特的羟脯
氨酸(Hyp)连接的O-糖基化修饰是羟脯
氨酸富集糖蛋白(HRGPs)中的常见过程。这种修饰通过在脯
氨酸残基的4位进行翻译后羟基化发生,其中一些随后在生成的Hyp上发生O-糖基化,这在一些分泌的肽类激素中也存在,例如拟南芥植物中的
CLAVATA3 (CLV3)。成熟的活性CLV3是一个十三肽,与β-L-Araf-(1→2)-β-L-Araf-(1→2)-β-L-Araf在肽序列中心的Hyp残基连接,例如Arg-Thr-Val-Hyp-Ser-Gly-Hyp(L-Arafn)-Asp-Pro-Leu-His-His-His (n = 3)。我们在这里报告了合成所有糖型(Araf0–3CLV3)的拟南芥植物分泌和修饰的CLV3糖肽。通过NAP醚介导的IAD实现了对Hyp衍
生物的高度立体选择性β-阿拉伯
呋喃糖基化,这是合成CLV3糖肽的关键步骤,并有效地应用于合成寡
阿拉伯糖基化羟脯
氨酸[Hyp(L-Araf1–3)]衍
生物。使用COMU作为偶联试剂,通过Fmoc固相肽合成引入了[Hyp(L-Araf0–3)]衍
生物,并进一步延伸至CLV3糖肽。