FIBRINOGEN BINDING AND VIRULENCE OF P GINGIVALIS

牙周病仍然是老年人牙齿脱落的主要原因。 成年人口。虽然再生程序的进展 继续下去，预防这些疾病的可能性仍然是最大的 很有吸引力。在构成牙周的许多细菌中 微生物区系，只有一小部分与启动有关 和人类牙周病的进展。目前的研究支持 牙龈卟啉单胞菌(Pg)对人类的致病作用 牙周炎。PG可能引发牙周炎或牙周炎的机制 导致这种疾病的组织破坏的特征是 目前还不清楚。我们已经鉴定并提纯了一个细胞 PG的表面相关半胱氨酸蛋白酶(赖氨酰内肽酶) 似乎还有一种纤维蛋白原和纤维连接蛋白结合蛋白。这 M-r150,000蛋白称为FBP。此外，我们还克隆了一个 编码纤维蛋白原和纤维连接蛋白结合的PG DNA片段 活性，并包含高度共有序列的DNA 与克隆的血凝素基因部分编码DNA的相似性 来自另一种PG菌株。到目前为止所获得的实验数据 提示PG，赖氨酸的三个假定毒力决定因素 内肽酶活性、纤维蛋白原和纤维连接蛋白结合活性以及 血凝活性可能是同一PG蛋白的功能。 这是一种耐人寻味的可能性，我们建议检验这一假设。 或者，归属的FBP功能可以位于单独的 交配的蛋白质。 提出了三个具体的目标：1)表征编码 纤维蛋白原结合蛋白，FBP，并在大肠杆菌中表达，2) 确定归属于FBP的功能是否可以分离，并研究 FBP基因产物的结构/功能关系，3) 确定FBP的底物专一性并确定其相似性 这种酶对其他半胱氨酸蛋白酶的作用。 这项研究的结果将澄清几个之间的关系 推测的PG毒力因子，将产生关于 可能是一种新的多功能PG细胞表面蛋白水解酶，并将 深入了解半胱氨酸蛋白酶的催化机制。 最重要的是，从这些研究中获得的信息不仅将 为PG的发病机制提供了新的见解，但可能 还允许设计具有高度选择性的治疗剂， 具体干扰FBP的单一或多个功能。是这样的 代理人可能有助于实现这项研究的长期目标，即 制定策略，在早期遏制牙周炎的发展 传染的过程。

Periodontal diseases continue to be a major cause of tooth loss in the adult human population. While advances in regenerative procedures proceed, the possibility of preventing these diseases remains most appealing. Of the many bacteria that comprise the periodontal microbiota, only a small number have been implicated in the initiation and progression of human periodontal diseases. Current research supports Porphyromonas gingivalis (Pg) as an etiologic agent of human periodontitis. The mechanisms by which Pg may initiate periodontitis or contribute to the tissue destruction characteristic of the disease are unknown at this time. We have identified and purified a cell surface-associated cysteine protease (lysyl endopeptidase) of Pg that also appears to be a fibrinogen and fibronectin binding protein. This M-r 150,000 protein is denoted FBP. In addition, we have cloned a fragment of Pg DNA which encodes a fibrinogen and fibronectin binding activity, and contains DNA that shares a high degree of sequence similarity with DNA encoding a portion of a hemagglutinin gene cloned from another strain of Pg. The experimental data obtained to date suggest that three putative virulence determinants of Pg, a lysyl endopeptidase activity, a fibrinogen and fibronectin binding activity and a hemagglutinating activity may be functions of the same Pg protein. This is an intriguing possibility and we propose to test this hypothesis. Alternatively, the ascribed FBP functions may be located on separate proteins that copurify. Three Specific Aims are proposed: 1) characterize the gene encoding the fibrinogen binding protein, fbp, and express the gene in E. coli, 2) determine if the functions ascribed to FBP can separated, and study structure/function relationships of the fbp gene product (FBP), 3) determine the substrate specificity of FBP and determine the similarity of this enzyme to other cysteine proteases. The results of this study will clarify the relationships between several putative virulence factors of Pg, will generate new information about what may be a novel multifunctional cell surface protease of Pg, and will provide insight into the catalytic mechanisms of cysteine proteases. Most importantly, information derived from these studies will not only provide new insights into the mechanisms of pathogenesis of Pg, but may also allow the design of highly selective therapeutic agents that could specifically interfere with single or multiple functions of FBP. Such agents may help achieve the long range goal of this research, which is to develop strategies to arrest the development of periodontitis early in the infectious process.