GLUCAN BINDING PROTEINS OF ORAL STREPTOCOCI

变形链球菌被认为是该病的主要病原菌 龋齿。 变形链球菌最突出的毒力因子包括 它的酸尿度和合成葡聚糖的能力，促进 与牙齿表面的附着力。 最近的研究表明 粘附和聚集机制的复杂性。 变形链球菌 物种至少有三种葡萄糖基转移酶（GTF），它们是 能够合成多种形式的葡聚糖。 此外， 变形链球菌的葡聚糖结合蛋白（GBP），这似乎是变形链球菌所独有的 该物种被假设有助于粘附和 形成粘性斑块。 该提案旨在确定角色 GBP 将葡聚糖与细胞表面结合。 特别是， GBP 的表达将与蔗糖的可用性有关，并且 GBP 在细胞表面和各种形式的葡聚糖的结合能力 将进行测试以评估英镑的相对贡献， 葡聚糖聚合物和 GTF 在粘附和斑块形成中的作用。 见面 为实现这些目标，提出了以下具体目标： 1) 将 GBP 表达水平对蔗糖利用率和其他环境的影响 pH值和厌氧等参数。 2）确定泛函 GBP 和 GTF 重复区域的相似性。 具体来说，融合 将通过交换重复区域来创建蛋白质以确定 对葡聚糖结合和 GTF 酶活性的影响。 3）使用 合成的寡肽竞争性抑制GBP与 葡聚糖，从而评估不同域的相对重要性 GBP 与葡聚糖的结合。 4) 检验 GBP 和 GTF 充当的假设 细胞上可溶性和不溶性葡聚糖粘附之间的桥梁 表面。 5) 克隆并表征葡聚糖结合凝集素的基因 (GBL) 唐氏链球菌。 确定进化相关性 gbl 和 gbp，以及它们结构和功能的相似之处 编码的蛋白质产物。 这些实验的结果应该导致 为了更好地了解葡聚糖结合蛋白如何 变形链球菌有助于牙菌斑形成和龋齿 过程。

Streptococcus mutans is recognized as the principal etiologic agent of dental caries. The most prominent virulence factors of S. mutans include its aciduricity, and its ability to synthesize glucans which promote adherence to the tooth surface. Recent studies have demonstrated the complexity of the mechanisms of adhesion and aggregation. S. mutans species have at least three glucosyltransferase (GTF) enzymes which are capable of synthesizing various forms of glucan. Additionally, the glucan-binding protein (GBP) of S. mutans, which appears to be unique to this species, has been hypothesized to contribute to adhesion and the formation of cohesive plaque. This proposal seeks to determine the role of GBP in binding glucans to the cell surface. In particular, the expression of GBP will be related to sucrose availability, and the binding ability of GBP at the cell surface and to various forms of glucan will be tested in order to evaluate the relative contributions of GBP, glucan polymers, and GTFs in adhesion and plaque formation. To meet these objectives the following specific aims are proposed: 1) Relate the level of GBP expression to sucrose availability and other environmental parameters such as pH and anaerobiosis. 2) Determine the functional similarity of the GBP and GTF repeat regions. Specifically, fusion proteins will be created by exchanging the repeat regions to determine the effects on glucan binding and GTF enzymatic activity. 3) Use synthesized oligopeptides to competitively inhibit the binding of GBP to glucans and thereby evaluate the relative importance of different domains of GBP to glucan binding. 4) Test the hypothesis that GBP and GTFs act as bridges between soluble and insoluble glucan adherence on the cell surface. 5) Clone and characterize the gene for the glucan-binding lectin (GBL) of Streptococcus downei. Determine the evolutionary relatedness of gbl and gbp, and the structural and functional similarities of their encoded protein products. The results from these experiments should lead to a better understanding of how the glucan binding proteins of the mutans streptococci contribute to plaque formation and the caries process.