Chen X S, Stehle T, Harrison S C
Howard Hughes Medical Institute and Department of Molecular and Cellular Biology, Harvard University, Boston, MA 02138, USA.
EMBO J. 1998 Jun 15;17(12):3233-40. doi: 10.1093/emboj/17.12.3233.
A complex of the polyomavirus internal protein VP2/VP3 with the pentameric major capsid protein VP1 has been prepared by co-expression in Escherichia coli. A C-terminal segment of VP2/VP3 is required for tight association, and a crystal structure of this segment, complexed with a VP1 pentamer, has been determined at 2.2 A resolution. The structure shows specific contacts between a single copy of the internal protein and a pentamer of VP1. These interactions were not detected in the previously described structure of the virion, but the location of VP2 in the recombinant complex is consistent with features in the virion electron-density map. The C-terminus of VP2/VP3 inserts in an unusual, hairpin-like manner into the axial cavity of the VP1 pentamer, where it is anchored strongly by hydrophobic interactions. The remainder of the internal protein appears to have significant flexibility. This structure restricts possible models for exposure of the internal proteins during viral entry.
通过在大肠杆菌中共表达，制备了多瘤病毒内部蛋白VP2/VP3与五聚体主要衣壳蛋白VP1的复合物。VP2/VP3的C末端片段是紧密结合所必需的，并且已经以2.2埃的分辨率确定了该片段与VP1五聚体复合的晶体结构。该结构显示内部蛋白的单个拷贝与VP1五聚体之间存在特异性接触。在先前描述的病毒体结构中未检测到这些相互作用，但重组复合物中VP2的位置与病毒体电子密度图中的特征一致。VP2/VP3的C末端以一种不寻常的发夹状方式插入VP1五聚体的轴向腔中，并通过疏水相互作用在那里牢固地锚定。内部蛋白的其余部分似乎具有很大的灵活性。这种结构限制了病毒进入过程中内部蛋白暴露的可能模型。
