DIFFERENCE IMAGING OF ADENOVIRUS - BRIDGING THE RESOLUTION GAP BETWEEN X-RAY CRYSTALLOGRAPHY AND ELECTRON-MICROSCOPY
DIFFERENCE IMAGING OF ADENOVIRUS - BRIDGING THE RESOLUTION GAP BETWEEN X-RAY CRYSTALLOGRAPHY AND ELECTRON-MICROSCOPY
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DOI：
10.1002/j.1460-2075.1993.tb05919.x
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发表时间：
1993-07-01
期刊：
影响因子：
11.4
通讯作者：
BURNETT, RM
中科院分区：
文献类型：
--
作者：
STEWART, PL;FULLER, SD;BURNETT, RM
X射线结晶学提供了蛋白质和小病毒的原子分辨结构，而电子显微镜则以较低的分辨率提供了关于较大组装组织的补充结构信息。这两种技术的新组合已经弥合了这一分辨率差距，并揭示了形成人类2型腺病毒衣壳的各种结构成分。用近似的对比度传递函数对来自低温电子显微镜照片的完整病毒的图像重建进行去卷积，以减轻显微镜的扭曲。从240份主要衣壳蛋白的晶体结构中计算出一个模型衣壳，并过滤到正确的分辨率。从修正后的重建中减去计算出的衣壳，得到了一个三维差异图，揭示了稳定病毒粒子的次要蛋白质。穿透小关节边缘六邻体衣壳的细长密度被归因于多肽IIIa，这是病毒粒子组装所必需的成分。衣壳内表面连接六角环的密度被命名为多肽VI，这是一种结合DNA的成分。识别接触五色子碱基的六邻体区域表明了先前提出的细胞进入过程中发生的事件的结构机制。
While X-ray crystallography provides atomic resolution structures of proteins and small viruses, electron microscopy provides complementary structural information on the organization of larger assemblies at lower resolution. A novel combination of these two techniques has bridged this resolution gap and revealed the various structural components forming the capsid of human type 2 adenovirus. An image reconstruction of the intact virus, derived from cryo-electron micrographs, was deconvolved with an approximate contrast transfer function to mitigate microscope distortions. A model capsid was calculated from 240 copies of the crystallographic structure of the major capsid protein and filtered to the correct resolution. Subtraction of the calculated capsid from the corrected reconstruction gave a three-dimensional difference map revealing the minor proteins that stabilize the virion. Elongated density penetrating the hexon capsid at the facet edges was ascribed to polypeptide IIIa, a component required for virion assembly. Density on the inner surface of the capsid, connecting the ring of peripentonal hexons, was assigned as polypeptide VI, a component that binds DNA. Identification of the regions of hexon that contact the penton base suggests a structural mechanism for previously proposed events during cell entry.