利用EDA融合标签高效表达猪圆环病毒2型壳蛋白

原核生物作为宿主细胞被广泛应用于异源蛋白质的重组表达，并且为生物活性蛋白质的制备提供了一种高效、经济的方法，因而在分子生物学中得到普遍的应用。然而，病毒蛋白在使用原核重组表达系统进行重组表达时，会出现病毒蛋白溶解性差和表达量低等问题。因此，通过使用各种融合标签以增加目的重组蛋白的表达量和溶解性成为有效的方法。本研究通过使用3种融合标签（EDA标签、MBP标签和GST标签）以获得表达量高的可溶性重组表达猪圆环病毒2型壳蛋白；并比较3种融合标签对该蛋白表达量、溶解性和稳定性的影响。研究结果表明，EDA标签可以显著提高重组表达的猪圆环病毒2型壳蛋白表达量，并且能够增强该蛋白的稳定性；MBP标签可增强重组表达的猪圆环病毒2型壳蛋白表达量，但是不能改善该蛋白的稳定性；GST标签能够增强该重组表达蛋白的表达量，但是不能增强该蛋白的溶解性和稳定性。本研究将EDA作为PCV2-CP蛋白的融合标签，显著提高PCV2-CP-EDA重组蛋白的表达量和增强该重组蛋白的稳定性，为病毒蛋白的可溶性重组表达提供了一种新的融合标签。

EDA is an Effective Fusion Tag for Porcine Circovirus 2 Capsid Protein Expression in Escherichia coli

The recombinant expression of heterologous proteins in prokaryotes provides a highly efficient and economical method for production of bioactive proteins, and is therefore widely used in molecular biology. However, prokaryotic recombinant expression systems are often limited by poor solubility and low expression of viral proteins. Therefore, various fusion tags are used to increase solubility and quantity of the desired recombinant protein. To our knowledge, the present study is the first to utilize the E. coli 2-keto-3-deoxy-6-p hosphogluconate (KDPG) aldolase (EDA) tag to improve the expression of soluble recombinant porcine circovirus 2 capsid protein (PCV2-CP). We compared the effects of maltose binding protein (MBP), the glutathione-S-transferase (GST), and EDA tags on protein expression, solubility, and stability. We found that the use of the EDA tag enabled a significant increase in both the expression level and stability of the recombinant PCV2-CP protein. These results show that EDA represents an efficient tag for the improvement of the solubility and stability of PCV2-CP expressed in E. coli. Our findings support that the EDA fusion tag could be used as a viral protein fusion tag.