中文摘要：

【目的】COG1732蛋白是结核分枝杆菌H37Rv菌株中的一个ATP-结合盒转运蛋白的底物结合蛋白,但其蛋白质三维结构及其生物学功能尚未明了,生物信息学分析表明COG1732蛋白可能做为参与渗透调节剂向细胞内转运过程中的底物识别过程,进一步改变跨膜结构域。本研究通过表达,纯化COG1732蛋白用于蛋白质晶体生长分析。【方法】针对结核分枝杆菌的一个ABC转运蛋白（ABC transporter）的胞外底物结合域COG1732。通过原核表达的方法,将表达COG1732的序列构建到带有T7启动子的载体pet28b,通过使用大肠杆菌表达系统BL21（DE3）大量表达COG1732蛋白。并通过镍亲和色谱和离子交换色谱的方法将COG1732蛋白纯化。将纯化好的COG1732蛋白浓缩至浓度为70mg/ml。分装保存到-80冰箱。并进行结晶条件的筛选。【结果】纯化的COG1732蛋白用悬滴气相扩散法得到了棒状晶体。【结论】成功构建了COG1732蛋白的原核表达载体﹑建立了表达纯化策略并获得了初步结晶的实验条件,为最终解析其三维结构奠定了基础。

英文摘要：

[Object] COG1732 protein is one of the ATP-binding cassette substrate binding proteins for Myeobacterium tuberculosis H37Rv. COG1732 protein three-dimension structure and function are not identify, bioinformation analysis have shown that COG1732 protein maybe participate in osmosis uptake into cell and identify substance. And change transmembrane structure domain. In this study, COG1732 protein was purified for crystal and analyze their structural features [method] For the ABC transporter substrate binding domain COG1732 of Mycobacterium tuberculosis H37Rv, use prokaryotic recombinant expression, the COG1732 gene was inserted into pet28b with T7 promoter, and the plasmid was transformed into E.coli BL21 （DE3） to over- express. Target protein was purified by nickel affinity chromatography and ions exchange chromatography. Purified COG1731 protein concentrated to 70mg/ml, aliquot and stored at -80 freezer for crystal screen.[result] Get crystal of target protein COG1732 with haggle vapor diffusion mothed [conclusion] We have successfully constructed COG1732 protein prokaryotic expression vector, established a prefect purification protocol of recombinant protein, determined the crystal condition, and built the foundation to resolved its structure.