STRUCTURE OF THE RECEPTORS FOR ORAL BACTERIAL ADHESINS

牙龈炎症是由口腔内的植物群定植引起的 以链球菌和革兰氏阳性杆菌为主， 通过菌毛凝集素与 多糖受体 细菌间的分子基础 粘附导致牙菌斑的形成， 将研究齿龈炎和牙周病的发生。 将对微生物的分子结构进行研究 负责种属特异性细菌相互作用的受体， 是口腔定植所必需的。 上的现有数据 分类学、生态学、共聚集特性和与特定 抗体将用于选择代表性菌株， 血链球菌，其荚膜多糖已知作为 放线菌菌毛凝集素的受体。 的 荚膜重复亚基的共价化学结构 将测定所选菌株的多糖。 来自分离于细胞中的重复亚基的寡糖片段 结构研究的过程将可用作探针， 细菌抗原的免疫反应性和作为 凝集素受体位点。 荚膜多糖的结构 相关的血链球菌菌株将与 与抗体和放线菌凝集素的反应性， 区分免疫显性碳水化合物位点和 凝集素受体活性 结构中使用的方法 决心将强调高分辨率核磁共振 (NM)光谱学，包括1H和13 C的完整归属 ~ 1H、~（13）C和~（31）P NMR信号的光谱和耦合相关性。 活性中心的三维构象 多糖将由NMR数据确定，特别是1H核 Overhauser增强（NOE），1H-1H和13 C-1H邻位偶联 相关性与计算机分子建模相结合。

Gingival inflammation is initiated by colonization of the mouth by flora dominated by streptococci and gram-positive rods which have been shown to coaggregate by the interaction of fimbrial lectins with polysaccharide receptors. The molecular basis of the interbacterial adherence leading to the formation of dental plaque and subsequent initiation of gingivitis and periodontal disease will be investigated. Studies will be carried out on the molecular structure of the microbial receptors responsible for species specific bacterial interactions which are required for colonization of the oral cavity. Existing data on the taxonomy, ecology, coaggregation properties and reactions with specific antibodies will be used to select representative strains of Streptococcus sanguis whose capsular polysaccharides are know to act as the receptors for the fimbrial lectins of Actinomyces species. The covalent chemical structure of the repeating subunit of the capsular polysaccharides of the selected strains will be determined. Oligosaccharide fragments from the repeating subunit isolated in the course of the structural studies will be available for use as probes of the immunological reactivity of bacterial antigens and as probes of the lectin receptor sites. The structures of the capsular polysaccharides of related Streptococcus sanguis strains will be correlated with the reactivity both with antibodies and with Actinomyces lectins in order to distinguish the immunodominant carbohydrate site and the site of the lectin receptor activity. The methodology to be used in the structure determination will emphasize high resolution nuclear magnetic resonance (NM) spectroscopy including complete assignments of the 1H and the 13C spectra and coupling correlation between 1H, 13C and 31P NM signals. The three dimensional conformation of the active sites of the polysaccharide will be determined from NM data, in particular 1H nuclear Overhauser enhancement (NOE), 1H-1H and 13C-1H vicinal coupling correlations in combination with computer molecular modeling.