SYNTHESIS AND CONFORMATION OF GLYCOPEPTIDES

病毒糖蛋白的免疫识别可能受其 糖基化 例如，HIV-1的Gp 120由50%的碳水化合物组成 并且与许多其他糖蛋白一起含有糖基化位点 在B和T细胞决定簇内或附近。 极有可能 糖基化影响B细胞和T细胞的识别， 稳定公认的结构。 碳水化合物的免疫原性作用 与蛋白质片段连接的部分难以寻址，除非 准备合适工具的方法就在手边。 这项建议是 重点是这些工具（糖肽）的合成和评估 糖基化对免疫相关肽构象的影响 识别. 我们建议扩展固相合成方法，我们用它来 合成携带Asn（GlcNAc）残基糖肽， 糖之间有O-糖基键的支链糖链 部分。 这些结构模仿自然发生的结构。 我们将 使用物理化学方法如CD和NMR来测量影响 不同的碳水化合物链结合到特定的和非 表位肽构象上的特定位置。 的 将获得的构象数据与 差异糖基化和亲本非糖基化肽通过T-和 B细胞 这些研究将为序列的最小准则提供线索 和糖肽结构刺激T细胞所必需的构象 并引发针对病毒糖蛋白的中和抗体产生。

Immune recognition of viral glycoproteins is probably influenced by their glycosylation. Gp120 of HIV-1, for example, consists of 50% carbohydrate and, together with many other glycoproteins, contains glycosylation sites within or close to both B- and T-cell determinants. It is highly likely that the glycosylation affects the recognition of both B- and T-cells by stabilizing the structures recognized. Immunogenic effects of carbohydrate moieties attached to protein fragments are difficult to address unless a method of preparing the appropriate tools is at hand. This proposal is focused on the synthesis of these tools (glycopeptides) and the assessment of glycosylation effects on the conformation of peptides involved in immune recognition. We propose to extend the solid-phase synthetic method, which we used to synthesize glycopeptides carrying Asn(GIcNAc) residue, to longer and branched carbohydrate chains with O-glycosydic bonds between the sugar moieties. These structures mimic the naturally occurring ones. We will use physical-chemical methods such as CD and NMR to measure the influence of incorporation of different carbohydrate chains to specific and non- specific positions on the conformation of epitopic peptides. The conformation data obtained will be compared with recognition of differentially glycosylated and parent non-glycosylated peptides by T- and B-cells. These studies will give clues to the minimal criteria of sequence and conformation necessary for glycopeptide structures to stimulate T cells and elicit neutralizing antibody production against viral glycoproteins.