幽门螺杆菌粘附素AlpB变异区域Asn130-Gly150的功能研究

The adaptive colonization of Helicobacter pylori (Hp) decides the bacteria infection and induction of diseases. In our previous study, by whole genome sequencing we observed 61 SNPs, which are associated its the adaptive colonization on Mongolian gerbils. One characteristic SNP is the deletion mutation of Asn130-Gly150 domain (V130-150) on adhesins AlpB, which continuous exist in the adaptive descendant generations. These results suggest that the V130-150 mutation may lead to the changes of the AlpB functions, which is closely related with the Hp adaptative colonization. In this study, we plan to clearify the relationship between the variation of V130-150 on AlpB and the clinical manifestations, then to construct Hp isogenic mutant with AlpB V130-150 deletion and analysis the function change caused by AlpB V130-150 mutation on cell models and animal models. In addition, to clarify the effect of V130-150 on AlpB structure and biochemical features, we decide to determine the crystal structure of AlpB and that with V130-150 deletion mutation and to compare their biochemical characteristics. The studies would provide a theoretical basis for the further elucidation of Hp colonization.

幽门螺杆菌（Hp）的适应性定植是其感染并致病的首要条件。课题组通过对Hp连续传代获得的沙鼠适应株全基因组测序结合SNP分析，筛选到稳定定植菌株的61个SNPs，其中粘附素AlpB的Asn130-Gly150结构域（V130-150）出现了连续16个氨基酸的缺失突变，且该突变在其后代中稳定存在，提示V130-150的突变可能导粘黏附素AlpB蛋白功能的改变，与Hp的适应定植密切相关。本研究拟在明确AlpB蛋白V130-150的变异与Hp感染的临床表现的关系基础上，构建Hp V130-150缺失突变株，通过细胞实验和沙鼠动物模型分析该功能结构域对Hp粘附定植的影响；同时通过晶体结构解析和体外生化特性分析，阐明V130-150对AlpB蛋白结构的影响，明确V130-150结构域在AlpB发挥其功能中的机制，为进一步阐明Hp适应性定植的机制提供实验依据。