Wang Xiangwen, Jin Qiaoying, Zou Li, Lin Xianghong, Lu Yonggang
IEEE/ACM Trans Comput Biol Bioinform. 2024 Nov-Dec;21(6):2496-2509. doi: 10.1109/TCBB.2024.3476619. Epub 2024 Dec 10.
Three-dimensional (3D) reconstruction in single-particle cryo-electron microscopy (cryo-EM) is a critical technique for recovering and studying the fine 3D structure of proteins and other biological macromolecules, where the primary issue is to determine the orientations of projection images with high levels of noise. This paper proposes a method to determine the orientations of cryo-EM projection images using reliable common lines and spherical embeddings. First, the reliability of common lines between projection images is evaluated using a weighted voting algorithm based on an iterative improvement technique and binarized weighting. Then, the reliable common lines are used to calculate the normal vectors and local -axis vectors of projection images after two spherical embeddings. Finally, the orientations of projection images are determined by aligning the results of the two spherical embeddings using an orthogonal constraint. Experimental results on both synthetic and real cryo-EM projection image datasets demonstrate that the proposed method can achieve higher accuracy in estimating the orientations of projection images and higher resolution in reconstructing preliminary 3D structures than some common line-based methods, indicating that the proposed method is effective in single-particle cryo-EM 3D reconstruction.
单颗粒冷冻电子显微镜（cryo-EM）中的三维（3D）重建是恢复和研究蛋白质及其他生物大分子精细三维结构的关键技术，其中的主要问题是确定具有高噪声水平的投影图像的方向。本文提出了一种利用可靠的共线和球面嵌入来确定冷冻电子显微镜投影图像方向的方法。首先，基于迭代改进技术和二值化加权，使用加权投票算法评估投影图像之间共线的可靠性。然后，在两次球面嵌入后，利用可靠的共线来计算投影图像的法向量和局部轴向量。最后，通过使用正交约束对齐两次球面嵌入的结果来确定投影图像的方向。在合成和真实冷冻电子显微镜投影图像数据集上的实验结果表明，与一些基于共线的方法相比，该方法在估计投影图像方向时能达到更高的精度，在重建初步三维结构时能获得更高的分辨率，这表明该方法在单颗粒冷冻电子显微镜三维重建中是有效的。
