Structure and Engineering of papaya mosaic virus nanoparticles

木瓜花叶病毒（PapMV）是一种弯曲的棒状植物病毒，是痘病毒科的成员。我们对这种病毒的组装过程和结构很感兴趣，因为它是所有其他弯曲杆状植物病毒的参考。最近，我们已经解决了80%的PapMV外壳蛋白（CP）的三维结构，并确定了参与蛋白质亚基和RNA主链之间相互作用的重要残基。此外，我们还开发了一种基于大肠杆菌生产的重组CP的体外组装试验，允许测试几种突变体。基于这一独特的专业知识，我们建议通过对PapMV CP的定向突变进一步提高我们对其结构的理解，并测试其自组装成纳米颗粒的能力。这项研究将证实我们的模型，并进一步提高我们对这种病毒结构的理解。我们将特别关注PapMV CP的c端，并试图阐明PapMV CP 3D结构中这一“缺失部分”的结构。我们将尝试在该病毒CP的C端确认Bio-Informatic预测的平行螺旋状螺旋。最后，我们在PapMV CP结构方面的专业知识将使我们能够开发一个新的平台，这将成为设计新型杀菌剂的基础。预计抗菌肽（magainin）在PapMV纳米颗粒表面的融合将导致具有更高抗菌裂解活性的工程纳米颗粒。我们将使用具有更好稳定性的CP的突变形式来进一步提高杀菌剂活性和纳米颗粒的储存期限。这个研究项目是令人兴奋的，因为它结合了PapMV CP结构的基本方面和纳米技术创新工具的开发和设计。

Papaya mosaic virus (PapMV) is a flexuous rod shape plant virus that is the member of the potexvirus family. We are interested in the assembly process and the structure of this virus because it is a reference for all the other flexuous rod shape plant viruses. Recently, we have resolved the 3D structure of 80 per cent of the PapMV coat protein (CP) and identified important residues involved in the interaction between the protein subunits and the RNA backbone. In addition, we have developed an in vitro assembly assay based on the use of recombinant CP produced in E. coli allowing testing several mutants. Based on this unique expertise, we propose to further improve our understanding of the structure of the PapMV CP through directed mutations in the CP and test their ability to self-assemble into nanoparticles. This study will permit to confirm our model and further improve our understanding of the structure of this virus. We will give a special attention to the C-terminus of the PapMV CP and attempt to elucidate the structure of this 'missing part' of the PapMV CP 3D structure. We will attempt to confirm the parallel coiled-coil predicted by Bio-Informatic at the C terminus of the CP of this virus. Finally, our expertise on the structure of the PapMV CP will allow us developing a novel platform that will become the basement for the design of a new class of bactericide. It is anticipated that the fusion of antibacterial peptides (magainin) at the surface of PapMV nanoparticles will lead to engineered nanoparticles with improved anti-bacterial lytic activities. We will use mutated form of the CP that harbour improved stability to further increase the bactericide activity and the length of the period of storage of the nanoparticles. This research program is exciting because it combines fundamental aspects of the structure of the PapMV CP and the development and design of an innovative tool in nanotechnology.