Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.
Structure. 2017 Dec 5;25(12):1875-1886.e7. doi: 10.1016/j.str.2017.11.001.
Some viruses use phosphatidylinositol phosphate (PIP) to mark membranes used for genome replication or virion assembly. PIP-binding motifs of cellular proteins do not exist in viral proteins. Molecular-docking simulations revealed a putative site of PIP binding to poliovirus (PV) 3C protein that was validated using nuclear magnetic resonance spectroscopy. The PIP-binding site was located on a highly dynamic α helix, which also functions in RNA binding. Broad PIP-binding activity was observed in solution using a fluorescence polarization assay or in the context of a lipid bilayer using an on-chip, fluorescence assay. All-atom molecular dynamics simulations of the 3C protein-membrane interface revealed PIP clustering and perhaps PIP-dependent conformations. PIP clustering was mediated by interaction with residues that interact with the RNA phosphodiester backbone. We conclude that 3C binding to membranes will be determined by PIP abundance. We suggest that the duality of function observed for 3C may extend to RNA-binding proteins of other viruses.
有些病毒利用磷脂酰肌醇磷酸（PIP）来标记用于基因组复制或病毒组装的膜。细胞蛋白的 PIP 结合基序不存在于病毒蛋白中。分子对接模拟揭示了脊髓灰质炎病毒（PV）3C 蛋白与 PIP 结合的一个假定位点，该位点通过核磁共振波谱得到了验证。PIP 结合位点位于一个高度动态的α螺旋上，该螺旋也参与 RNA 结合。使用荧光偏振测定法在溶液中或使用芯片上的荧光测定法在脂质双层中观察到广泛的 PIP 结合活性。3C 蛋白-膜界面的全原子分子动力学模拟显示 PIP 聚集，可能还有 PIP 依赖性构象。PIP 聚集是通过与与 RNA 磷酸二酯骨架相互作用的残基相互作用介导的。我们得出结论，3C 与膜的结合将取决于 PIP 的丰度。我们建议，3C 观察到的双重功能可能扩展到其他病毒的 RNA 结合蛋白。
