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坦布苏病毒E蛋白和结构域Ⅱ的生物信息学分析及多克隆抗体制备

Bioinformatic Analysis and Polyclonal Antibody Preparation of Tembusu Virus E Protein and ED-Ⅱ

  • 摘要: 综合运用多种生物信息学软件,对坦布苏病毒(Tembusu virus,TMUV)囊膜E蛋白及结构域Ⅱ(ED-Ⅱ)蛋白进行了预测分析,指导蛋白截短设计;构建重组表达质粒并原核表达纯化E、ED-Ⅱ重组蛋白,制备鼠源E、ED-Ⅱ蛋白多克隆抗体,采用棋盘方阵滴定法建立了间接ELISA检测方法并测定抗体效价,应用Western blotting和间接免疫荧光分析(IFA)鉴定多克隆抗体特异性。结果表明:(1)生物信息学分析显示,E蛋白编码501个氨基酸残基,属于亲水性蛋白,含有2个跨膜区域,不含信号肽;共预测到50个磷酸化修饰位点及2个N-糖基化位点(154和314 aa);E蛋白的二级结构组成中α-螺旋、延伸链、β-转角、无规则卷曲的占比分别为22.55%、31.14%、11.78%和34.53%;三级结构预测表明,E蛋白整体包含3个结构域(ED-Ⅰ、ED-Ⅱ和ED-Ⅲ)。(2)构建原核表达载体pET-28a-E和pET-28a-ED-,纯化获得E、ED-Ⅱ重组蛋白并进行验证;免疫小鼠制备鼠源多克隆抗体E、ED-Ⅱ的效价分别高达1∶1638400和1∶409600,Western blotting和IFA验证多克隆抗体具有良好的特异性。

     

    Abstract: Multiple bioinformatics tools were used to predict the Tembusu virus(TMUV) envelope E protein and its domain Ⅱ(ED Ⅱ) the transmembrane domains. Recombinant expression plasmids were constructed, expressed and purified the recombinant E and EDⅡ proteins in a prokaryotic system. Mouse-derived polyclonal antibodies against the E and EDⅡ proteins were prepared. An indirect ELISA method was established using a checkerboard titration to determine antibody titers, and the specificity of the antibodies was evaluated by Western blotting and indirect immunofluorescence assay(IFA). The results showed that:(1)Bioinformatics analysis revealed that the E protein consists of 501 amino acid residues, is a hydrophilic protein with two transmembrane regions and no signal peptide. A total of 50 phosphorylation sites and two N-glycosylation sites(154 and 314 aa) were predicted. In the secondary structure of the E protein, α-helix, extended strand, β-turn, and random coil account for 22.55%, 31.14%, 11.78%, and 34.53%, respectively. Tertiary structure prediction indicated that the E protein consists of three domains(EDⅠ, EDⅡ, and EDⅢ). The prokaryotic expression vectors pET-28a-E and pET-28a-ED- were successfully constructed, and the recombinant E and EDⅡ proteins were purified and verified. Mouse-derived polyclonal antibodies against these proteins exhibited high titers of up to 1:1638400 and 1:409600, respectively. Both Western blotting and IFA confirmed the excellent specificity of the antibodies.