Gabi Pragier, Ph.D., Tel Aviv University

Title: A common-lines approach for three-dimensional modeling of molecules in cryo-electron microscopy

One of the primary challenges in single particle reconstruction in cryo-electron microscopy is to find a three-dimensional model of a molecule using its two-dimensional noisy projection images. In the first part of the talk, I will focus on molecules without symmetry and suggest a distribution-independent method for estimating the unknown imaging orientations of all projection images. The two-way handedness ambiguity in the estimation of the relative orientation between each pair of images is removed by casting the problem as a graph partitioning problem. In the second part of the talk, I will focus on molecules that have an $n$-fold cyclic symmetry for which existing common-lines-based methods are not applicable. Our suggested method utilizes self-common-lines which induce identical lines within the same image. We show that the location of self-common-lines admits quite a few favorable geometrical constraints, thus enabling a high detection rate even in a noisy setting. The results in this talk are part of the Ph.D. thesis of Gabi Pragier, done under the supervision of Yoel Shkolnisky.