Algorithmic robustness to preferred orientations in single particle analysis by CryoEM
Carlos Óscar S. Sorzano, Dmitry A. Semchonok, Su‐Chang Lin, Yi‐Ching Lo, José Luis Vilas, Amaya Jiménez-Moreno, Marcos Gragera, Santiago Vacca, David Maluenda, Marta Martínez, Erney Ramírez-Aportela, R. Melero, Ana Cuervo, José Javier Conesa, Pablo Conesa, Patricia Losana, Laura del Caño, J. Jiménez de la Morena, Yunior C. Fonseca, Rubén Sánchez-García, David Střelák, E. Fernández-Giménez, F. de Isidro, David Herreros, Panagiotis L. Kastritis, R. Marabini, Barry D. Bruce, J.M. Carazo
Abstract
The presence of preferred orientations in single particle analysis (SPA) by cryo-Electron Microscopy (cryoEM) is currently one of the hurdles preventing many structural analyses from yielding high-resolution structures. Although the existence of preferred orientations is mostly related to the grid preparation, in this technical note, we show that some image processing algorithms used for angular assignment and three-dimensional (3D) reconstruction are more robust than others to these detrimental conditions. We exemplify this argument with three different data sets in which the presence of preferred orientations hindered achieving a 3D reconstruction without artifacts or, even worse, a 3D reconstruction could never be achieved.