GLUCAN BINDING PROTEINS OF ORAL STREPTOCOCI

变形链球菌是公认的主要病原体， 龋病 S.变异体包括 它耐酸性和它合成葡聚糖的能力， 附着在牙齿表面。 最近的研究表明， 粘附和聚集机制的复杂性。 S.变形 物种具有至少三种葡糖基转移酶（GTF）， 能够合成各种形式的葡聚糖。 另夕h 葡聚糖结合蛋白（GBP）。变异体，这似乎是独特的， 这种物质，已被假设为有助于粘附， 形成粘性斑块。 本建议旨在确定 GBP结合葡聚糖到细胞表面。 特别是 GBP的表达与蔗糖的利用率有关， GBP在细胞表面的结合能力以及与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在粘附和菌斑形成中的作用。 满足 为了实现这些目标，提出了以下具体目标：1） GBP表达水平与蔗糖利用率和其它环境因子的关系 pH和厌氧等参数。2)确定函数 GBP和GTF重复区的相似性。 具体来说，Fusion 蛋白质将通过交换重复区域来产生， 对葡聚糖结合和GTF酶活性的影响。3)使用 竞争性抑制GBP与 从而评估不同结构域的相对重要性 GBP与葡聚糖的结合。4)测试GBP和GTF充当 细胞上可溶性和不溶性葡聚糖粘附之间的桥梁 面5)葡聚糖结合凝集素基因的克隆和鉴定 (GBL)唐氏链球菌 确定进化相关性 GBL和GBP的结构和功能相似性， 编码的蛋白质产物。 这些实验的结果 为了更好地了解葡萄糖的葡聚糖结合蛋白如何 变形链球菌有助于牙菌斑的形成和龋齿 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.