Arheit, MarcelCastano-Diez, DanielThierry, RaphaelAbeyrathne, PriyankaGipson, Bryant RStahlberg, Henning2020-02-132020-02-132020-02-132012-10-0710.1007/978-1-62703-176-9_11https://infoscience.epfl.ch/handle/20.500.14299/165366Electron crystallography of membrane proteins uses cryo-transmission electron microscopy to record images and diffraction patterns of frozen-hydrated 2D crystals. Each two-dimensional (2D) crystal is only imaged once, at one specific tilt angle, and the recorded images can be automatically processed with the 2dx/MRC software package. Processed image data from non-tilted and tilted 2D crystals then need to be merged into a 3D reconstruction of the membrane protein structure. We here describe the process of the 3D merging, using the 2dx software system.text::book/monograph::book part or chapter