Electron cryotomography of immature HIV-1 virions reveals the structure of the CA and SP1 Gag shells
Electron cryotomography of immature HIV-1 virions reveals the structure of the CA and SP1 Gag shells
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DOI：
10.1038/sj.emboj.7601664
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发表时间：
2007-04-18
期刊：
影响因子：
11.4
通讯作者：
Jensen, Grant J.
中科院分区：
文献类型：
--
作者：
Wright, Elizabeth R.;Schooler, Jordan B.;Jensen, Grant J.
逆转录病毒的主要结构元件包含在单个多蛋白Gag中，Gag在人类免疫缺陷病毒1型（HIV-1）中包含MA、CA、间隔肽1（SP1）、NC、SP2和p6多肽。在未成熟的HIV-1病毒粒子中，Gag的结构域呈放射状排列，N-末端MA结构域位于膜上，C-末端NC-SP2-p6区域最靠近中心。在这里，我们报告的三维结构的个别未成熟的HIV-1病毒粒子，获得电子冷冻断层扫描。Gag多聚蛋白的同心壳清晰可见，不同Gag层的径向投影显示CA和SP1壳内的六边形顺序。平均有序的单位细胞导致一个模型，其中每个CA六聚体是由一束六个SP1螺旋稳定。这个模型表明，为什么SP1间隔是必不可少的组装的Gag晶格和SP1和CA之间的裂解如何作为一个结构开关控制成熟。
The major structural elements of retroviruses are contained in a single polyprotein, Gag, which in human immunodeficiency virus type 1 (HIV-1) comprises the MA, CA, spacer peptide 1 (SP1), NC, SP2, and p6 polypeptides. In the immature HIV-1 virion, the domains of Gag are arranged radially with the N-terminal MA domain at the membrane and C-terminal NC-SP2-p6 region nearest to the center. Here, we report the three-dimensional structures of individual immature HIV-1 virions, as obtained by electron cryotomography. The concentric shells of the Gag polyprotein are clearly visible, and radial projections of the different Gag layers reveal patches of hexagonal order within the CA and SP1 shells. Averaging well-ordered unit cells leads to a model in which each CA hexamer is stabilized by a bundle of six SP1 helices. This model suggests why the SP1 spacer is essential for assembly of the Gag lattice and how cleavage between SP1 and CA acts as a structural switch controlling maturation.