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增强型绿色荧光蛋白(Enhanced green fluorescent protein，EGFP)是绿色荧光蛋白(Green fluorescent protein，GFP)的突变体[19]。GFP的分子量为27 kD，它的表达没有种属特异性，不需要辅助因子、底物或其他基因表达产物的协助作用，灵敏度高[20]。EGFP在480 nm波长的激发下可以发射出比GFP亮35倍的绿色荧光，使得其观察和检测更为准确。本研究采用的EGFP可以直接在荧光显微镜下对转导的活体细胞进行观察，观察后的细胞可继续用于后续的实验，为YARA介导的融合蛋白转导能力的研究提供了一种理想的目的蛋白。
本研究通过基因重组的方法构建出原核表达质粒pET15bYARAEGFP，转化大肠杆菌BL21(DE3)，然后用IPTG诱导表达出融合蛋白YARAEGFP。根据融合蛋白的N端带有6个组氨酸标签，利用镍柱金属螯合亲和层析，纯化出YARAEGFP。纯化后的蛋白可以用特异性的抗组氨酸“标签”抗体方便地进行检测。纯化蛋白的SDSPAGE电泳和Western blot结果显示YARAEGFP分子量约为29 kD，与预测的相符。本研究为观察YARA介导的EGFP在离体和在体的转导能力进而为利用YARA作为携带具有潜在治疗作用的蛋白质的载体研究奠定了基础。
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