口蹄疫病毒氨基酸改造对其病毒样颗粒稳定性的影响

Effect of amino acid site modification on stability of foot-and-mouth disease virus-like particles

摘要:

病毒样颗粒 (Virus like particles，VLPs) 的稳定性是目前影响口蹄疫VLPs疫苗质量的主要因素。为进一步提升口蹄疫VLPs疫苗的质量，基于口蹄疫病毒三维空间结构，通过动力学分析软件设计并筛选出3个氨基酸改造位点。经点突变试剂盒成功制备出上述3种突变型重组质粒，转化大肠杆菌Escherichia coli BL21菌株后经体外诱导表达，Ni离子层析柱纯化后，SDS-PAGE结果证明3种氨基酸突变不影响目标蛋白的表达。体外组装获得的3种突变型VLPs稳定性研究结果发现，内部疏水性侧链氨基酸的引入使VLPs的形态变得更加均一 (N4017W)，且其稳定性比其他两种VLPs明显提高。结果表明，衣壳内部疏水性作用力有助于VLPs的形成且有助于维持衣壳的稳定性，为提高VLPs疫苗质量提供了新的研究思路，有助于推进VLPs疫苗的发展。

关键词:病毒样颗粒，三维构象，突变体，稳定性，同源建模，口蹄疫病毒

Abstract:

The stability of virus-like particles (VLPs) is currently the main factor affecting the quality of foot-and-mouth disease VLPs vaccines. In order to further improve the quality of the VLPs vaccine of foot-and-mouth disease (FMD), three amino acid modification sites were designed and screened through kinetic analysis software, based on the three-dimensional structure of FMDV. The three mutant recombinant plasmids were successfully prepared by the point mutation kit, transformed into Escherichia coli strain BL21 and expressed in vitro. After purification by Ni ion chromatography column, SDS-PAGE proved that the three amino acid mutations did not affect the expression of the target protein. The results of the stability study of three FMD mutant VLPs obtained by in vitro assembly show that the introduction of internal hydrophobic side chain amino acids made the morphology of VLPs more uniform (N4017W), and their stability was significantly improved compared to the other two VLPs. The internal hydrophobic force of the capsid contributes to the formation of VLPs and helps to maintain the stability of the capsid, providing new experimental ideas for improving the quality of VLPs vaccines, and helping to promote the development of VLPs vaccines.

Key words:virus like particles, three-dimensional structure, mutant, stability, homology modeling, foot-and-mouth disease virus