B7-PE40新型重组融合外毒素的分子生物学特性预测

The Prediction of the Molecular Biology Characteristics of Recombinant Fusion Exotoxin B7-1-Linker-PE40 and B7-2-Linker-PE40

为探讨构建的重组外毒素融合蛋白B7 1 Linker PE4 0和B7 2 Linker PE4 0及其接头设计的合理性 ,应用核酸和蛋白质序列分析软件系统GOLDKEY ,对上述重组外毒素融合蛋白的柔性、抗原性、亲水性、表位和二级结构等分子生物学特性进行了计算机模拟预测。结果发现它们分别保留了B7 1,B7 2和PE4 0的表位特征 ,没有出现新的表位 ,其柔性接头处的抗原性也极低。与B7 1,B7 2和PE4 0的一、二级结构比较发现 ,这两种融合蛋白各有数个氨基酸残基改变 ,有的氨基酸改变可轻微影响融合蛋白的二级结构。原核表达的两个融合蛋白经Western印迹分析显示 ,它们能分别与B7 1,B7 2和PE4 0单克隆抗体发生特异性结合 ,表明它们较好地保留了B7和PE4 0的抗原性和空间结构 ,与预测的结果一致。提示预测结果会有助于我们研究该系列融合蛋白的体内、外生物学效应 ,以及设计构建新的其他融合蛋白。

In order to confirm the reasonability of designed recombinant exotoxin B7-1-Linker-PE40 and B7-2-Linker-PE40, their molecular biology characteristics, such as flexibility, antigenicity, hydrophilicity, epitope and secondary structure, were predicted by using a computer software GOLDKEY. It had been found that the recombinant fusion exotoxin had kept the epitope characterstics of B7-1, B7-2 and PE40, and had not got new epitope, and the antigenicity in flexible linker was extxemely low. The linker inserted in the recombinant fusion exotoxin had low epitope, low antigenicity and high flexibility. Compared to B7-1, B7-2 and PE40, there are several amino acid residues changes in B7-1-Linker-PE40 and B7-2-Linker-PE40, respectively, which might have some effect on secondary structure of the recombinant fusion exotoxins. Western blot analysis revealed that both B7-1-Linker-PE40 and B7-2-Linker-PE40 could bind specifically with antibodies against B7-1, B7-2 and PE40, respectively. The result of Western blot was consistant with the computer prediction that the recombinant proteins retain the antigenicity and spacial structure of B7 and PE40. It is suggested that both fusion proteins designed and constructed were resonable and computer analysis would be helpful for us to study the biological activity of the recombinant fusion exotoxin B7-1-Linker-PE40 and B7-2-Linker-PE40 and construct other recombinant proteins further.