Cryogenic electron microscopy (cryo-EM) can yield near-atomic resolution structures of highly ordered macromolecular complexes. Often however some subunits bind in a flexible manner, have different symmetry from the rest of the complex, or are present in sub-stoichiometric amounts, limiting the attainable resolution. We have developed a general method for the localized three-dimensional reconstruction of such subunits earlier (Ilca et al. 2015 Nature Commununications). In this project we implemented Localized Reconstruction as a plugin (Locarec) for Scipion (Abrishami et al. 2020 Progress in Biophysics & Molecular Biology).

We contributed an option to "relax symmetry" to RELION, a popular software for cryo-EM single particle image analysis.  This functionality can be used by giving option --relax_sym, followed by the dominant symmetry you want to relax. In many cases it can achive what another common strategy called "symmetry expansion" can, just more efficiently and in some cases also more accurately. This is now part of the official version of RELION. For our earlier development version please see the GitHub page.