DESIGN AND FUNCTION OF SALIVARY CYCLONEOGLYCOPEPTIDE

该子项目的长期目标是利用现有的 有关选定唾液结构特征的信息 分子来设计具有增强生物活性的改良物质， 活动 在这些“结构性”中使用的出发点 模拟”研究集中在主要的富含脯氨酸的糖蛋白 人腮腺唾液（PRG）。 在PRG的生物 功能是与碳水化合物结合的能力 血链球菌表面的粘附素。 两者 寡糖的一级结构和 N-连接的连接点周围的肽已经被 在我们的实验室里。 虽然结构的特殊性 PRG-血链球菌相互作用已经被 证明，这种特异性的构象基础 仍然没有定义。 本研究报告将审查 肽构象周围的N-糖基化位点的PRG在 这种特异性。 根据我们得到的β-转角构象 据报道，新糖肽将使用完整的 (Asn/寡糖）组分和环肽 被设计成β转弯 环肽具有 极大地限制可能结构的数量的优点 相应的线性肽可能具有的。 两者 将检测“环糖肽”及其线性对应物 用于标记后与血链球菌的结合亲和力 125 I的肽部分。 两种环肽的结构 环糖肽和新糖肽 将用X射线晶体学、核磁共振 共振光谱（NMR）和计算机建模。 然后，β-转弯类型的改变将被诱导， D-氨基酸异构体的取代 环糖肽。 在此之后，额外的细菌 将进行结合分析。 这种方法将允许 生物活性与给定构象的直接相关性 因此定义了环糖肽的这一方面， 至于其在PRG-血链球菌中的相对重要性， 交互. 预计这些类似物将具有 生物效价至少等于天然PRG的生物效价 分子，因为我们实际上是在重建一个最小值， 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植物群。

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.