The Cryo-Electron Microscopy Structure of Feline Calicivirus Bound to Junctional Adhesion Molecule A at 9-Angstrom Resolution Reveals Receptor-Induced Flexibility and Two Distinct Conformational Changes in the Capsid Protein VP1
The Cryo-Electron Microscopy Structure of Feline Calicivirus Bound to Junctional Adhesion Molecule A at 9-Angstrom Resolution Reveals Receptor-Induced Flexibility and Two Distinct Conformational Changes in the Capsid Protein VP1
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DOI：
10.1128/jvi.05621-11
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发表时间：
2011-11-01
影响因子：
5.4
通讯作者：
Goodfellow, Ian G.
中科院分区：
文献类型：
--
作者：
Bhella, David;Goodfellow, Ian G.
杯状病毒科（Caliciviridae）是含有小的二十面体正义RNA的病毒，并且包括人诺如病毒（其是传染性急性胃肠炎的主要原因）和猫杯状病毒（FCV）（其引起猫的呼吸道疾病和口腔炎）。FCV附着和进入由猫连接粘附分子A（fJAM-A）介导，所述猫连接粘附分子A结合到衣壳的外表面，诱导衣壳中的构象变化，这对于病毒脱壳可能是重要的。在这里，我们提出了我们的病毒受体相互作用和随后的构象变化的结构调查的结果。冷冻电子显微镜和三维图像重建被用来以亚纳米分辨率解决用受体可溶性片段装饰的病毒的结构。在最初的重建中，衣壳蛋白VP 1和fJAM-A的P结构域解析较差。分选实验导致FCV-fJAM-A复合物在诱导的构象变化之前和之后以及在三个过渡态中的改进的重建。这些数据表明，P结构域在fJAM-A结合后变得柔性，导致二十面体对称性的丧失。此外，两个不同的构象变化，观察到的AB二聚体的P域的一个anticceptor旋转高达15度，而倾斜的P域远离二十面体2倍轴中看到的CC二聚体。通过将fJAM-A和VP 1的高分辨率坐标拟合到重建的密度图来计算推定的接触残基列表，突出显示病毒和受体中对病毒附着和进入重要的区域。
Caliciviridae are small icosahedral positive-sense RNA-containing viruses and include the human noroviruses, a leading cause of infectious acute gastroenteritis and feline calicivirus (FCV), which causes respiratory illness and stomatitis in cats. FCV attachment and entry is mediated by feline junctional adhesion molecule A (fJAM-A), which binds to the outer face of the capsomere, inducing a conformational change in the capsid that may be important for viral uncoating. Here we present the results of our structural investigation of the virus-receptor interaction and ensuing conformational changes. Cryo-electron microscopy and three-dimensional image reconstruction were used to solve the structure of the virus decorated with a soluble fragment of the receptor at subnanometer resolution. In initial reconstructions, the P domains of the capsid protein VP1 and fJAM-A were poorly resolved. Sorting experiments led to improved reconstructions of the FCV-fJAM-A complex both before and after the induced conformational change, as well as in three transition states. These data showed that the P domain becomes flexible following fJAM-A binding, leading to a loss of icosahedral symmetry. Furthermore, two distinct conformational changes were seen; an anticlockwise rotation of up to 15 degrees of the P domain was observed in the AB dimers, while tilting of the P domain away from the icosahedral 2-fold axis was seen in the CC dimers. A list of putative contact residues was calculated by fitting high-resolution coordinates for fJAM-A and VP1 to the reconstructed density maps, highlighting regions in both virus and receptor important for virus attachment and entry.