Spanish National Research Council (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
Dept. Biochemistry and Biophysics, University of California, San Francisco, USA.
J Struct Biol. 2019 Mar 1;205(3):1-6. doi: 10.1016/j.jsb.2019.01.005. Epub 2019 Jan 26.
Recently, it has been shown that the resolution in cryo-tomography could be improved by considering the sample motion in tilt-series alignment and reconstruction, where a set of quadratic polynomials were used to model this motion. One requirement of this polynomial method is the optimization of a large number of parameters, which may limit its practical applicability. In this work, we propose an alternative method for modeling the sample motion. Starting from the standard fiducial-based tilt-series alignment, the method uses the alignment residual as local estimates of the sample motion at the 3D fiducial positions. Then, a scattered data interpolation technique characterized by its smoothness and a closed-form solution is applied to model the sample motion. The motion model is then integrated in the tomographic reconstruction. The new method improves the tomogram quality similar to the polynomial one, with the important advantage that the determination of the motion model is greatly simplified, thereby overcoming one of the major limitations of the polynomial model. Therefore, the new method is expected to make the beam-induced motion correction methodology more accessible to the cryoET community.
最近的研究表明，通过在倾斜系列对准和重建中考虑样本运动，可以提高低温断层摄影术的分辨率，其中使用一组二次多项式来模拟这种运动。这种多项式方法的一个要求是优化大量的参数，这可能限制其实际适用性。在这项工作中，我们提出了一种替代方法来模拟样本运动。从基于标准基准的标准倾斜系列对准开始，该方法将对准残差用作 3D 基准位置处样本运动的局部估计值。然后，应用具有平滑性和闭式解的散点数据插值技术来模拟样本运动。然后将运动模型集成到断层重建中。新方法可以改善断层图像质量，类似于多项式方法，具有重要的优势，即大大简化了运动模型的确定，从而克服了多项式模型的主要限制之一。因此，预计新方法将使基于光束诱导运动校正的方法更容易为低温电子断层扫描社区所接受。
