中文摘要：

目的：在大肠杆菌中构建并表达3种FimH重组蛋白，并对FimH重组蛋白的培养条件进行优化，制备高纯度FimH重组蛋白。方法：采用原核表达载体pET28a构建出能表达FimH的重组质粒，并分别对诱导温度、IPTG浓度、诱导时间等条件进行优化，以提高重组蛋白的产量和增大其可溶性，最后以亲和层析分离纯化3种FimH重组蛋白。结果：成功构建出表达大肠杆菌（K12，BL21）和沙门氏菌（S．T．）FimH的原核表达载体pET28a—K12／BL21／S．T．，经酶切、测序和WesternBlot鉴定，目的蛋白表达正确。在适当浓度的IPTG诱导，15℃震荡培养20h，可使FimH的表达量达到最大，分离纯化的蛋白在SDS—PAGE中显示为一条带。结论：本研究构建以3种FimH为表面呈现系统的表达载体，3种FimH基因和预测蛋白结构略有差异。本研究为后续研究3种蛋白生物活性差异及其靶向M细胞的免疫佐剂活性提供物质基础。

英文摘要：

Objective： To express and purify three recombinant FimH in E. coli BL21（DE3）plysS and optimize the cultivation regulation. Methods： The recombinant FimH was expressed in the PET28a vector, it was detected by SDS-PAGE under different cultivation conditions , including temperature, concentration of IPTG and time. After that, the expressed recombinant protein FimH was purified using immobilized metal ion affinity chromatography and identified by SDS -PAGE. Results： It was found that the expression level of FimH achieved the highest when the BL21 （DE3）plysS had been induced for 20h with suitable IPTG beginning from strain density of A600 -0.6 at 15℃. FimH was purified from the soluble phase by means of His-tag affinity chromatography on a nlckel- charged column. Conclusion： This study aims to build three FimH as expression vector of the surface rendering system ,analyse FimH gene and predict protein structure.