人源性防御素HD-5的原核表达及抗真菌作用的初步研究

Prokaryotic Expression and Antifungal Activity of Human α Defensin-5 Protein

目的构建pQE-30Xa/HD-5原核表达载体,纯化重组蛋白并进行抗真菌活性的初步鉴定。方法以pcDNA3.1(+)/HD-5为模板,聚合酶链反应(PCR)扩增编码HD-5成熟肽的基因。构建pQE-30Xa/HD-5重组表达载体,并对重组质粒进行酶切、基因序列分析。将鉴定正确的质粒转化入大肠杆菌M15后进行异丙基-D-硫代半乳糖苷(IPTG)诱导表达,对表达产物进行十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)鉴定。通过镍柱亲和层析纯化蛋白并进行蛋白复性,蛋白免疫印迹(Western blot)鉴定纯化产物。以KB纸片法初步验证纯化获得的重组蛋白对白色假丝酵母菌的抑菌活性。结果成功克隆了HD-5基因并构建了重组质粒pQE-30Xa/HD-5。重组质粒在大肠杆菌M15中诱导表达出HD-5融合蛋白;Western blot分析结果显示纯化后的融合蛋白与目的蛋白相符;KB纸片法证实纯化后的融合蛋白对白色假丝酵母菌具有一定的抑菌活性。结论成功构建HD-5原核表达载体,经诱导表达后纯化获得具有良好抑菌活性的HD-5融合蛋白。

Objective To construct the prokaryotic expression vector for HD-5 and purify the recombinant HD-5 protein then analyze its antifungal activity. Methods The HD-5 gene was cloned by PCR, then was inserted into prokary-otic expression plasmid pQE-30Xa to construct pQE-30Xa/HD-5. After sequencing, pQE-30Xa/HD-5 was transformed in-to E.coli M15 cells. Its expression was induced by IPTG and confirmed by SDS-PAGE. The recombinant protein was purified through Ni-NTA affinity purification system. The antifungal activity was tested by disk diffusion method. Results HD-5 gene and pQE-30Xa/HD-5 vector were obtained successfully. E.coli M15 strains was used to express HD-5 fusion protein. After purification, the fusion protein was confirmed by Western blot. The disk diffusion test confirmed that the fusion pro-tein can inhibit Candida albicans. Conclusion Expression vector pQE-30Xa/HD-5 was successfully constructed. The HD-5 fusion protein was expressed in E.coli successfully, which showed a certain degree of antifungal activity.