Cryo-Electron Microscopy Structure of Adenovirus Type 2 Temperature-Sensitive Mutant 1 Reveals Insight into the Cell Entry Defect
Cryo-Electron Microscopy Structure of Adenovirus Type 2 Temperature-Sensitive Mutant 1 Reveals Insight into the Cell Entry Defect
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DOI：
10.1128/jvi.00331-09
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发表时间：
2009-08-01
影响因子：
5.4
通讯作者：
Stewart, Phoebe L.
中科院分区：
文献类型：
--
作者：
Silvestry, Mariena;Lindert, Steffen;Stewart, Phoebe L.
通过冷冻电子显微镜单颗粒重建，确定2型腺病毒温度敏感突变体1（Ad 2 ts 1）的结构分辨率为10埃。Ad 2 ts 1在非允许温度下制备，含有衣壳蛋白IIIa、VI和VIII的前体形式;核心蛋白VII、X（mu）和末端蛋白（TP）;以及L1- 52 K蛋白。细胞进入研究表明，虽然Ad 2 ts 1可以结合柯萨奇病毒和Ad受体，并通过α v整联蛋白进行内化，但这种突变体不会从早期内体逃逸，并被靶向降解。Ad 2 ts 1结构与成熟Ad结构的比较表明Ad 2 ts 1具有不同的核心架构。Ad 2 ts 1核心与二十面体衣壳密切相关，这种连接可能由前蛋白IIIa和VI介导。六邻体空腔内的密度被分配给前蛋白VI，膜破坏试验表明，六邻体屏蔽的成熟和前体形式的蛋白VI的裂解活性。在Ad 2 ts 1中的五邻体基底的内表面似乎通过与前蛋白IIIa的相互作用锚定到核心。我们的结构分析表明，这些连接到核心抑制顶点蛋白的释放，并导致Ad 2 ts 1的细胞进入缺陷。
The structure of the adenovirus type 2 temperature-sensitive mutant 1 (Ad2ts1) was determined to a resolution of 10 angstrom by cryo-electron microscopy single-particle reconstruction. Ad2ts1 was prepared at a nonpermissive temperature and contains the precursor forms of the capsid proteins IIIa, VI, and VIII; the core proteins VII, X (mu), and terminal protein (TP); and the L1-52K protein. Cell entry studies have shown that although Ad2ts1 can bind the coxsackievirus and Ad receptor and undergo internalization via alpha v integrins, this mutant does not escape from the early endosome and is targeted for degradation. Comparison of the Ad2ts1 structure to that of mature Ad indicates that Ad2ts1 has a different core architecture. The Ad2ts1 core is closely associated with the icosahedral capsid, a connection which may be mediated by preproteins IIIa and VI. Density within hexon cavities is assigned to preprotein VI, and membrane disruption assays show that hexon shields the lytic activity of both the mature and precursor forms of protein VI. The internal surface of the penton base in Ad2ts1 appears to be anchored to the core by interactions with preprotein IIIa. Our structural analyses suggest that these connections to the core inhibit the release of the vertex proteins and lead to the cell entry defect of Ad2ts1.