CTER Rapid estimation of CTF parameters with error assessment
CTER Rapid estimation of CTF parameters with error assessment
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DOI：
10.1016/j.ultramic.2014.01.009
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发表时间：
2014-05-01
期刊：
影响因子：
2.2
通讯作者：
Spahn, Christian M. T.
中科院分区：
文献类型：
--
作者：
Penczek, Pawel A.;Fang, Jia;Spahn, Christian M. T.
在结构电子显微镜中，对比度传递函数(CTF)参数的准确估计，特别是散焦和散光，对于显微图像质量的初始评估和随后的结构确定都是至关重要的。由于配备新一代相机的现代显微镜数据收集速度的提高，能够快速且最少地进行用户干预的CTF估计也很重要。最后，为了将用户手动筛选显微照片的必要性降至最低，有必要提供对拟合参数值的误差的评估。在这项工作中，我们介绍了CTER，一种以计算效率为特点的CTF参数估计方法。该方法的效率使其适用于高分辨率的EM数据采集，并允许使用统计重采样技术Bootstrap，该技术可产生估计的散焦和散光幅度和角度的标准偏差，从而便于筛选劣质显微图像数据的过程的自动化。更重要的是。CTER还输出由CTF的离散形式的倒数空间混叠和有限窗口大小施加的空间频率限制。我们使用在300千伏Tecnai Polara(FEU)上收集的数据集，在超分辨率Lion计数模式下使用K2 Summit DED相机来演示CTER的效率和准确性。使用CTER我们得到了80S核糖体的结构，其大亚基的分辨率为4.03埃，不包括散光参数的分辨率为3.85埃。(C)2014爱思唯尔公司版权所有
In structural electron microscopy, the accurate estimation of the Contrast Transfer Function (CTF) parameters, particularly defocus and astigmatism, is of utmost importance for both initial evaluation of micrograph quality and for subsequent structure determination. Due to increases in the rate of data collection on modern microscopes equipped with new generation cameras, it is also important that the CTF estimation can be done rapidly and with minimal user intervention. Finally, in order to minimize the necessity for manual screening of the micrographs by a user it is necessary to provide an assessment of the errors of fitted parameters values. In this work we introduce CTER, a CTF parameters estimation method distinguished by its computational efficiency. The efficiency of the method makes it suitable for high-LhroughpuL EM data collection, and enables the use of a statistical resampling technique, bootstrap, that yields standard deviations of estimated defocus arid astigmatism amplitude arid angle, thus facilitating the automation of the process of screening out inferior micrograph data. Furthermore. CTER also outputs the spatial frequency limit imposed by reciprocal space aliasing of the discrete form of the CTF and the finite window size. We demonstrate the efficiency and accuracy of CTER using a data set collected on a 300 kV Tecnai Polara (FEU using the K2 Summit DED camera in super resoluLion counting mode. Using CTER we obtained a structure of the 80S ribosome whose large subunit had a resolution of 4.03 angstrom without, and 3.85 angstrom with, inclusion of astigmatism parameters.(C) 2014 Elsevier B.V. All rights reserved