DESIGN AND FUNCTION OF SALIVARY CYCLONEOGLYCOPEPTIDE

这个子项目的长期目标是利用现有的 关于选定唾液的结构特征的信息 分子设计具有增强生物功能的改良物质 活动。在这些“结构”中使用的起点 “模仿”研究主要集中在富含脯氨酸的糖蛋白上。 取自人腮腺唾液(PRG)。在PRG的生物学中 功能是与碳水化合物结合的能力 血链球菌表面的粘附素。这两个 低聚糖的一级结构及其构象 N-连接连接点周围的多肽已经 在我们的实验室得到了澄清。虽然结构上的特殊性 PRG与血链球菌的相互作用已被 证明，这种特异性的构象基础 仍未定义。本研究将探讨以下方面的作用 酪氨酸氨基转移酶N-糖基化位点周围的肽构象 这种专一性。基于我们已有的Beta-Turn构象 据报道，一种新的糖肽将用完整的 PRG的(天冬氨酸/低聚糖)组分和一个环肽 被设计成以贝塔转弯的形式存在。环肽具有 极大地限制可能结构的数量的优势 相应的线状多肽可能具有。这两个 将测试“旋糖肽”和它的线性对应物 标记后与血链球菌的结合亲和力 多肽部分与125I。两种环肽的结构 和多肽、环状糖肽和新糖肽 将使用x射线结晶学、核磁学 共振光谱(核磁共振)和计算机模拟。 贝塔转弯类型的改变随后将被诱导 D-氨基酸异构体在大豆中的替代 气旋糖肽。紧随其后的是额外的细菌 将进行约束性分析。这种方法将允许 生物活性与给定构象的直接关联 因此定义了环状糖肽的这一方面 关于其在PRG中的相对重要性--血链球菌 互动。预计这些类比将有一个 生物学效力至少等同于原生PRG 分子，因为我们实际上是在重建最小 功能域。可以获得的信息可以 为人工唾液的开发提供了理论基础 可以选择性地调节口腔菌群。

The long range goal of this Subproject is to utilize current information on structural characteristics of selected salivary molecules to design improved substances with enhanced biological activity. The starting point to be used in these "structural mimicry" studies focuses on the major proline-rich glycoprotein from human parotid saliva (PRG). Among PRG's biological functions is the ability to interact with carbohydrate binding adhesins on the surface of Streptococcus sanguis. Both the primary structure of the oligosaccharide and the conformation of the peptide around the N-linked attachment point has been elucidated in our laboratory. While the structural specificity of the PRG-Streptococcus sanguis interaction has been demonstrated, the conformational basis for this specificity remains undefined. The present study will examine the role of peptide conformation around the N-glycosylation site of PRG in this specificity. Based on the beta-turn conformation we have reported, a neoglycopeptide will be synthesized using the intact (Asn/oligosaccharide) component of PRG and a cyclopeptide designed to exist as a beta-turn. The cyclopeptide has the advantage of greatly limiting the number of possible structures the corresponding linear peptide might have. Both the "cycloneoglycopeptide" and its linear counterpart will be tested for binding affinity with Streptococcus sanguis after labeling the peptide moiety with 125I. The structures of both the cyclopeptide and peptide and the cycloneoglycopeptide and neoglycopeptide will be elucidated using x-ray crystallography, nuclear magnetic resonance spectroscopy (NMR) and computer modeling. Alteration of the beta-turn type will then be induced by substitution of D-amino acid isomers in the cycloneoglycopeptides. Following this, additional bacterial binding assays will be carried out. This methodology will allow a direct correlation of biological activity with a given conformation of peptide, thus defining this aspect of the cycloneoglycopeptide as to its relative importance in the PRG-Streptococcus sanguis interactions. It is anticipated that these analogs will have a biological potency at least equal to that of the native PRG molecule since we are in effect reconstructing a minimum functional domain. The information which can be obtained may provide a rationale for development of artificial salivas which could selectively modulate the oral flora.