MOLECULAR BIOLOGY, PLATELET AGGREGTION, S. SANGUIS

人血小板聚集相关蛋白的分子生物学研究 血链球菌) 某些绿色链球菌(Agg+)菌株，包括 口腔共生植物区系中的主要成员。血链球菌， 体外诱导人血小板聚集。当绿色人种 链球菌进入体内，它们可能成为重要的病原体或 甚至某些严重人类疾病的病原体通过相互作用 与血小板有关的疾病，如细菌性心内膜炎、Beheet综合征等。 血链球菌的三种不同的表面抗原(adh+，Agg+)已经被 建议参与与血小板的相互作用，这是 I类抗原(粘附素)，II类抗原，也称为 血小板聚集相关蛋白(PAAP)和III类抗原， 它具有胞外ATPase活性。血链球菌细胞通过与血小板结合 I类抗原，然后II类抗原触发并激活 致密颗粒的释放和血小板的聚集， III类抗原通过水解释放的ATP来放大反应 从致密颗粒进入ADP。 在从血链球菌基因组中寻找PAAP基因的过程中， 编码65 kDa热休克蛋白(HSP65)的基因被发现 是大肠杆菌groEL基因和微囊藻hsp65基因的同源物。 肺结核。血链球菌hsp65基因的序列数据表明 与人类HSP65的同源物人PI蛋白基因也有很高的同源性。 对血链球菌65Kda热休克蛋白进行了纯化。决赛 蛋白质的同源性通过内部多肽序列得到了证实。 为了阐明血链球菌和PAAP的HSP65之间的差异， 用HSP65进行血小板聚集抑制试验 血缘沙门氏菌当血小板聚集被抑制时， 与HSP65预孵化。然而，HSP65似乎不那么有效，因为 考虑到其抑制血小板聚集的能力优于PAAP。 这两种蛋白质之间的另一个显著区别是 HSP65不包含PAAP中的血小板相互作用结构域 和胶原蛋白。 总之，从血链球菌中鉴定出HSP65可能 为研究自身免疫性疾病提供了有用的工具。这种蛋白质是 不同于之前在本实验中发现的PAAP。 关键词：基因、克隆、测序。血链球菌， 血小板：

Molecular Biology of the Platelet Aggregation-Associated Protein of Streptococcus sanguis) Certain strains of viridans streptococci (Agg+), including the predominant member of the oral commensal flora. Streptococcus sanguis, induce human platelets to aggregate in vitro. When viridans streptococci entered the body, they may become significant pathogens or even etiological agents of certain severe human diseases by interacting with platelets, such as bacterial endocarditis, Beheet's syndrome, etc. Three different surface antigens of S. sanguis (Adh+, Agg+) have been proposed to be involved in the interaction with platelets, which are class I antigen (adhesin), class II antigen, which is also called platelet-aggregation associated protein (PAAP), and class III antigen, which has ecto-ATPase activity. S. sanguis cells bind to platelets by class I antigen, and then class II antigen triggers and activates the release of the dense granules and the aggregation of platelets, the class III antigen amplifies the reaction by hydrolyzing ATP released from dense granules into ADP. While in search of the gene of the PAAP from genome of S. sanguis, a gene encoding a 65kDa heat shock protein (HSP65) was discovered, which is a homolog of the groEL gene of E. coli and hsp65 gene of M. tuberculosis. Sequence data from the hsp65 gene of S. sanguis indicated high homology also to human PI protein gene, a human homolog of hsp65. Purification of the 65Kda HSP from S. sanguis was conducted. The final identity of the protein was confirmed by internal peptide sequences. To clarify the differences between HSP65 of S. sanguis and PAAP, platelet aggregation inhibition assays were carried out with the HSP65 of S. sanguis. Platelet aggregation was inhibited when the platelets preincubated with the HSP65. However, the HSP65 seems less potent with regard to its ability to inhibite platelet aggregation than PAAP. Another significant difference between these two proteins is that the HSP65 does not contain the platelet interactive domain as in the PAAP and collagen. In conclusion, the identification of the HSP65 from S. sanguis may provide a useful tool to study antoimmune diseases. This protein is different from PAAP which has been identified from this lab previously. Key words: genes, cloning, sequencing. Streptococcus sanguis, platelet: