Kaukinen Pasi, Kumar Vibhor, Tulimäki Kirsi, Engelhardt Peter, Vaheri Antti, Plyusnin Alexander
Department of Virology, Haartman Institute, P.O. Box 21, FI-00014 University of Helsinki, Finland.
J Virol. 2004 Dec;78(24):13669-77. doi: 10.1128/JVI.78.24.13669-13677.2004.
The structure of the nucleocapsid protein of bunyaviruses has not been defined. Earlier we have shown that Tula hantavirus N protein oligomerization is dependent on the C-terminal domains. Of them, the helix-loop-helix motif was found to be an essential structure. Computer modeling predicted that oligomerization occurs via helix protrusions, and the shared hydrophobic space formed by amino acids residues 380-IILLF-384 in the first helix and 413-LI-414 in the second helix is responsible for stabilizing the interaction. The model was validated by two approaches. First, analysis of the oligomerization capacity of the N protein mutants performed with the mammalian two-hybrid system showed that both preservation of the helix structure and formation of the shared hydrophobic space are crucial for the interaction. Second, oligomerization was shown to be a prerequisite for the granular pattern of transiently expressed N protein in transfected cells. N protein trimerization was supported by three-dimensional reconstruction of the N protein by electron microscopy after negative staining. Finally, we discuss how N protein trimerization could occur.
布尼亚病毒核衣壳蛋白的结构尚未明确。此前我们已表明图拉汉坦病毒N蛋白的寡聚化依赖于C末端结构域。其中，螺旋-环-螺旋基序被发现是一种必需结构。计算机建模预测寡聚化通过螺旋突出发生，并且由第一个螺旋中的氨基酸残基380-IILLF-384和第二个螺旋中的413-LI-414形成的共享疏水空间负责稳定相互作用。该模型通过两种方法得到验证。首先，用哺乳动物双杂交系统对N蛋白突变体的寡聚化能力进行分析表明，螺旋结构的保留和共享疏水空间的形成对于相互作用都至关重要。其次，寡聚化被证明是转染细胞中瞬时表达的N蛋白呈颗粒状模式的先决条件。负染后通过电子显微镜对N蛋白进行三维重建支持了N蛋白三聚化。最后，我们讨论了N蛋白三聚化可能如何发生。
