医学免费论文:pET15bYARAEGFP原核表达质粒的构建及融合蛋白YARAEGFP的表达与纯化
【摘要】 目的:构建原核表达载体pET15bYARAEGFP,并进行YARAEGFP融合蛋白的表达和纯化。方法:用分子克隆技术构建出表达型载体pET15bYARAEGFP,在E.coli BL21(DE3)中表达融合蛋白YARAEGFP,并进行Ni2+NTA树脂柱亲和层析以纯化蛋白。结果:经测序证实成功构建了表达型载体pET15bYARAEGFP,YARAEGFP融合蛋白在E.coli BL21(DE3)中得到表达,纯化后的蛋白浓度为1.098 mg/mL。SDSPAGE和Western blot分析表明纯化蛋白为目的蛋白YARAEGFP。结论:已成功制备出YARAEGFP融合蛋白。
【关键词】 细胞穿透肽 增强型绿色荧光蛋白 原核表达 融合蛋白
Construction of Prokaryotic Expression Plasmid pET15bYARAEGFP and Expression and Purification of YARAEGFP Fusion Protein CHEN Sisi1,2,WANG Jianing2^,HUANG Yongzhang2,GUO Lingyun2,ZHENG Fei2 (1Cardiovascular Research Institute,Renmin Hospital,Wuhan University,Wuhan,Hubei 430060;2Institute of Clinical Medicine,Renmin Hospital,Yunyang Medical College,Shiyan,Hubei 442000,China)
Abstract:Objective To construct the expression vector pET15bYARAEGFP and express and purify the fusion protein YARAEGFP.Methods Two oligonucleotides encoding YARA were synthesized and annealed to generate YARAencoding DNA. The recombinant plasmid pET15bYARAEGFP was constructed by inserting YARAencoding DNA into pET15bEGFP. The fusion protein YARAEGFP induced with IPTG in E.coli BL21(DE3)was purified with Ni2+resin affinity chromatography and confirmed with SDSPAGE and western blot.Results Sequence analysis confirmed successful construction of the expression vector pET15bYARAEGFP,the fusion protein YARAEGFP was expressed and purified and its concentration was 1.098 mg/mL.SDSPAGE and Western blot demonstrated the fusion protein was YARAEGFP.Conclusion YARAEGFP fusion protein is successfully prepared医.学.全.在.线www.lindalemus.com.
Key words:Cell penetrating peptides;Enhanced green fluorescent protein;Prokaryotic expression;Fusion protein
自人类基因组计划的完成和蛋白组计划的实施以来,人们发现了许多生物大分子具有潜在的治疗价值。但细胞膜是脂质双分子层,具有选择通透性,这种天然屏障作用在保护细胞的同时也限制了生物大分子自由进入细胞内发挥作用。传统的将大分子物质转导入细胞内的常用方法有电穿孔、脂质体转染等,这些方法不但转导效率低,而且对转导的细胞均有毒副作用,且仅适用于体外实验。最近研究发现,某些蛋白质的结构区域具有将外源性蛋白转导入细胞内的特性,这些区域被称为蛋白转导结构域或细胞穿透肽[1],它能携带有治疗作用的蛋白质转导入细胞内并发挥相应的生物学效应,这使它有可能成为一种理想的蛋白转导载体。目前研究最为深入的是来源于人类免疫缺陷病毒反式激活因子的TAT蛋白转导结构域,其氨基酸序列为YGRKKRRQRRR。Choi领导的研究小组[2-8]已经证实了TATGFP、TATGDH、TATSOD和TATCAT等融合蛋白能转导入哺乳动物细胞内和皮肤组织。为了进一步提高细胞穿透肽的转导效率,Ho等[9]将TAT的氨基酸序列进行优化,合成了一种新的蛋白转导结构域即YARA,其氨基酸序列为YARAAARQARA,发现其转导效率为TAT的33倍。为了探讨YARA介导的融合蛋白的离体和在体转导能力,本研究设计合成了编码YARA的DNA序列,通过基因重组技术构建了原核表达质粒pET15bYARAEGFP,表达并纯化出YARAEGFP融合蛋白,为YARA介导的生物大分子EGFP穿透细胞能力的研究奠定了基础。