人体鼠双微体2 C端结构域ZF&RING 重组蛋白的表达、纯化及单体结构研究

目的:通过在大肠杆菌SUMO系统中对鼠双微体2(MDM2)C端结构域ZFRING(aa.300-491)进行构建并进行表达,酶切和纯化,从而得到MDM2蛋白C端结构域的单体结构,为其后续的晶体研究及MDM2非p53依赖途径的研究提供途径。方法:利用大肠杆菌SUMO表达系统对zfring基因进行重组构建。构建成功的表达载体经诱导表达优化后,通过Ni-NTA进行亲和层析纯化,并利用SDS-PAGE及Western blot鉴定分析。纯化后的融合蛋白经ULP1酶切得到目的蛋白ZFRING,并通过Hi Trap Q FF离子交换层析检验和去除杂质DNA。最后通过分子筛检验其蛋白结构。结果:构建了SUMO-ZFRING重组载体。重组载体在大肠杆菌高效可溶性表达,纯化并酶切后的目的蛋白ZFRING以单体形式存在。结论:通过原核表达、纯化、酶切及层析发鉴定,成功获得高稳定、高纯度且为单体结构的MDM2 C端结构域ZFRING蛋白,为后续关于MDM2,尤其是其非p53依赖途径的结构学和功能学提供了思路和途径。

The Expression, Purification and Monomer Structure Research of Human Oncoprotein MDM2 C-terminal -ZF&RING*

Objective:To present a new method to recombinantly express and purify the C-terminal Zinc Finger and RING domain of MDM2 (ZF&RING) in monomeric form, thus providing a new avenue for characterizing MDM2 p53-independent roles through future structure and function studies.Methods:ZF&RING gene was first constructed in SUMOexpression system. The expression vectors containing recombinant genes were purified by Ni-NTA affinity chromatography and analyzed by SDS-PAGE and western blot after optimized expressing in . The SUMO tag and DNA was removed by protease ULP1 and ion-exchange. The aggregation state of the purified ZF&RING was finally confirmed by size exclusion chromatography.Results:SUNO-zf&ring recombinant genes were constructed and the fusion protein highly soluble expressed in E.coli. After well purified and digested, the target ZF&RING was validated to be monomeric by Gel filtration chromatography.Conclusion:Through prokaryotic expression, purification and digestion, we successfully obtained human oncoprotein MDM2 C-terminal domain ZF&RING monomeric proteins with high stability and purity under physiological conditions. The purified protein could be used for further studies of structure and function relationships of MDM2 in p53-independent pathways.