Department of Mathematics and PACM, Princeton University, Fine Hall, Washington Road, Princeton, NJ 08544-1000, USA.
J Struct Biol. 2010 Mar;169(3):312-22. doi: 10.1016/j.jsb.2009.11.003. Epub 2009 Nov 17.
The single-particle reconstruction problem of electron cryo-microscopy (cryo-EM) is to find the three-dimensional structure of a macromolecule given its two-dimensional noisy projection images at unknown random directions. Ab initio estimates of the 3D structure are often obtained by the "Angular Reconstitution" method, in which a coordinate system is established from three projections, and the orientation of the particle giving rise to each image is deduced from common lines among the images. However, a reliable detection of common lines is difficult due to the low signal-to-noise ratio of the images. In this paper we describe a global self-correcting voting procedure in which all projection images participate to decide the identity of the consistent common lines. The algorithm determines which common line pairs were detected correctly and which are spurious. We show that the voting procedure succeeds at relatively low detection rates and that its performance improves as the number of projection images increases. We demonstrate the algorithm for both simulative and experimental images of the 50S ribosomal subunit.
电子晶体学显微镜（cryo-EM）的单粒子重建问题是在未知随机方向的二维噪声投影图像的情况下找到大分子的三维结构。3D 结构的从头估算通常通过“角度重建”方法获得，其中从三个投影中建立坐标系，并从图像之间的公共线推断出产生每个图像的粒子的方向。然而，由于图像的信噪比低，可靠地检测公共线是困难的。在本文中，我们描述了一种全局自校正投票程序，其中所有投影图像都参与决定一致公共线的身份。该算法确定了哪些公共线对被正确检测，哪些是虚假的。我们表明，投票程序在相对较低的检测率下成功，并且随着投影图像数量的增加，其性能得到提高。我们为 50S 核糖体亚基的模拟和实验图像演示了该算法。
