Jones Christopher T, Ma Lixin, Burgner John W, Groesch Teresa D, Post Carol B, Kuhn Richard J
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
J Virol. 2003 Jun;77(12):7143-9. doi: 10.1128/jvi.77.12.7143-7149.2003.
The capsid proteins of two flaviviruses, yellow fever virus and dengue virus, were expressed in Escherichia coli and purified to near homogeneity suitable for biochemical characterization and structure determination by nuclear magnetic resonance. The oligomeric properties of the capsid protein in solution were investigated. In the absence of nucleic acid, both proteins were predominantly dimeric in solution. Further analysis of both proteins with far-UV circular dichroism spectroscopy indicated that they were largely alpha-helical. The secondary structure elements of the dengue virus capsid were determined by chemical shift indexing of the sequence-specific backbone resonance assignments. The dengue virus capsid protein devoid of its C-terminal signal sequence was found to be composed of four alpha helices. The longest alpha helix, 20 residues, is located at the C terminus and has an amphipathic character. In contrast, the N terminus was found to be unstructured and could be removed without disrupting the structural integrity of the protein.
两种黄病毒（黄热病病毒和登革病毒）的衣壳蛋白在大肠杆菌中表达，并纯化至接近均一的程度，适合用于生物化学特性分析以及通过核磁共振确定结构。研究了衣壳蛋白在溶液中的寡聚特性。在没有核酸的情况下，两种蛋白在溶液中主要以二聚体形式存在。用远紫外圆二色光谱对两种蛋白进行的进一步分析表明，它们主要是α螺旋结构。通过对序列特异性主链共振归属进行化学位移索引，确定了登革病毒衣壳的二级结构元件。发现缺失C端信号序列的登革病毒衣壳蛋白由四个α螺旋组成。最长的α螺旋有20个残基，位于C端，具有两亲性。相比之下，发现N端是无结构的，可以去除而不破坏蛋白质的结构完整性。
