Tomographic subvolume alignment and subvolume classification applied to myosin V and SIV envelope spikes.
Tomographic subvolume alignment and subvolume classification applied to myosin V and SIV envelope spikes.
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DOI：
10.1016/j.jsb.2008.10.004
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发表时间：
2009-02
影响因子：
3
通讯作者：
Taylor, Kenneth A.
中科院分区：
文献类型：
--
作者：
Winkler, Hanspeter;Zhu, Ping;Liu, Jun;Ye, Feng;Roux, Kenneth H.;Taylor, Kenneth A.
电子层析成像是一种三维重建技术，广泛用于对大分子、大分子组件或整个细胞进行成像。与冷冻电子显微镜相结合，它能够在接近细胞体内条件的状态下可视化结构细节。在电子断层摄影术中，当样品围绕固定的轴线倾斜到不同的角度时，可以拍摄显微照片。由于机械的限制，角度倾斜范围是有限的。因此，3D图像的重建是缺失的数据，对于单轴倾斜序列来说，这被称为“缺失楔形”，这是倒易空间中无法通过实验获得傅里叶系数的区域。通过从原始断层图像中提取子体积、通过对准所提取的子体积、多变量数据分析、分类和分类平均来分析断层扫描数据，这导致了信噪比的增加和大量的数据减少。亚体积分析是区分大分子的非均相群体或大分子或大分子组合的构象以及表征大分子之间相互作用的有价值的工具。然而，由于楔形缺失导致原始断层图像中数据的缺乏，这一分析受到了阻碍。在这里，我们报告了我们的子体处理协议的改进，其中通过使用约束相关性和倒数空间中的加权平均来解决倒数空间中的丢失数据的问题。这些程序被应用于肌球蛋白V和猴免疫缺陷病毒(SIV)包膜尖峰的分析。我们还研究了缺失楔形对图像分类的影响，并通过生成模体的模型计算确定了可靠性界限。
Electron tomography is a technique for three-dimensional reconstruction, that is widely used for imaging macromolecules, macromolecular assemblies or whole cells. Combined with cryo-electron microscopy, it is capable of visualizing structural detail in a state close to in vivo conditions in the cell. In electron tomography, micrographs are taken while tilting the specimen to different angles about a fixed axis. Due to mechanical constraints, the angular tilt range is limited. As a consequence, the reconstruction of a 3D image is missing data, which for a single axis tilt series is called the “missing wedge”, a region in reciprocal space where Fourier coefficients cannot be obtained experimentally. Tomographic data is analyzed by extracting subvolumes from the raw tomograms, by alignment of the extracted subvolumes, multivariate data analysis, classification, and class-averaging, which results in an increased signal-to-noise ratio and substantial data reduction. Subvolume analysis is a valuable tool to discriminate heterogeneous populations of macromolecules, or conformations of a macromolecule or macromolecular assembly as well as to characterize interactions between macromolecules. However, this analysis is hampered by the lack of data in the original tomograms caused by the missing wedge. Here, we report enhancements of our subvolume processing protocols in which the problem of the missing data in reciprocal space is addressed by using constrained correlation and weighted averaging in reciprocal space. These procedures are applied to the analysis of myosin V and simian immunodeficiency virus (SIV) envelope spikes. We also investigate the effect of the missing wedge on image classification and establish limits of reliability by model calculations with generated phantoms.
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影响因子：
3
作者：
Liu, J;Reedy, MC;Taylor, KA
通讯作者：
Taylor, KA
影响因子：
3
作者：
Schmid, Michael F.;Booth, Christopher R.
通讯作者：
Booth, Christopher R.
HIV-1 包膜尖峰的冷冻电子断层扫描：三脚架状腿的进一步证据
影响因子：
6.7
作者：
Zhu P;Winkler H;Chertova E;Taylor KA;Roux KH
通讯作者：
Roux KH
影响因子：
5.6
作者：
Liu, Jun;Wu, Shenping;Taylor, Kenneth A.
通讯作者：
Taylor, Kenneth A.
影响因子：
2.2
作者：
Winkler, H;Taylor, KA
通讯作者：
Taylor, KA