Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA.
J Am Chem Soc. 2010 Mar 10;132(9):3211-6. doi: 10.1021/ja9104073.
Here we present a convergent on-resin glycosylamine coupling strategy for solid phase N-linked glycopeptide synthesis, and apply it to the synthesis of high mannose containing glycopeptides. In this strategy, the 2-phenylisopropyl protecting group is used as an orthogonal handle to create glycosylation sites on-resin after synthesis of nonglycosylated peptides. In addition to allowing selective deprotection of aspartic acid residues for creation of glycosylation sites, the 2-phenylisopropyl protecting group also efficiently suppresses aspartimide formation during peptide synthesis. The key step of on-resin glycosylamine coupling to an aspartic acid residue was first optimized for a small sugar, N-acetylglucosamine, and then applied to a much larger high mannose oligosaccharide, Man(8)GlcNAc(2). Satisfying coupling yields were obtained for both small and large sugars. The use of on-resin glycosylamine coupling simplifies purification of N-linked glycopeptides, and also allows convenient recovery of unreacted valuable large oligosaccharides. This approach was applied to the solid phase synthesis of glycosylated forms of the 34 amino acid HIV-1 gp41 C34 glycopeptide, which is an HIV-1 entry inhibitor. The HIV-1 entry inhibition assay of synthesized glycopeptides showed the retention of bioactivity of high mannose Man(8)GlcNAc(2)-C34.
在这里，我们提出了一种在树脂上的糖基胺偶联策略，用于固相 N-连接糖肽合成，并将其应用于高甘露糖含量糖肽的合成。在该策略中，2-苯基异丙基保护基用作正交手柄，在合成非糖基化肽后在树脂上创建糖基化位点。除了允许选择性脱保护天冬氨酸残基以创建糖基化位点外，2-苯基异丙基保护基还在肽合成过程中有效地抑制天冬酰胺形成。首先对小糖 N-乙酰葡萄糖胺进行了在树脂上糖基胺偶联到天冬氨酸残基的关键步骤的优化，然后将其应用于更大的高甘露糖寡糖 Man(8)GlcNAc(2)。小糖和大糖都获得了令人满意的偶联产率。在树脂上的糖基胺偶联简化了 N-连接糖肽的纯化，并且还允许方便地回收未反应的有价值的大寡糖。该方法应用于 HIV-1 gp41 C34 糖肽的糖基化形式的固相合成，该糖肽是一种 HIV-1 进入抑制剂。合成糖肽的 HIV-1 进入抑制测定表明保留了高甘露糖 Man(8)GlcNAc(2)-C34 的生物活性。
