SYNTHESIS AND CONFORMATION OF GLYCOPEPTIDES

病毒糖蛋白的免疫识别可能受其影响 糖基化。例如，HIV-1的gp120由50%的碳水化合物组成 与许多其他糖蛋白一起，含有糖基化位点。 在B细胞和T细胞决定簇内或接近B细胞决定簇。它极有可能是 糖基化通过影响B细胞和T细胞的识别 稳定已识别的结构。碳水化合物的免疫原性 附着在蛋白质片段上的部分很难解决，除非 准备适当工具的方法近在咫尺。这项建议是 重点介绍了这些工具(糖肽)的合成和评价 糖基化对免疫相关多肽构象的影响 承认。 我们提出了扩展固相合成法的方法，我们曾经使用过 合成携带天冬氨酸氨基转移酶(GIcNAc)残基的糖肽 糖链之间带有O-糖基键的支链碳水化合物 半个。这些结构模仿了自然发生的结构。我们会 使用CD和核磁共振等物理化学方法来测量影响 将不同的碳水化合物链结合到特定和非特定的 表位多肽构象上的特定位置。这个 获得的构象数据将与识别 不同糖基化多肽和亲本非糖化肽的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 并诱导产生针对病毒糖蛋白的中和抗体。

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.