Map Symmetry (cryo-EM)


Some molecules, such as viruses, have high internal symmetry so you can reduce the cryo-EM map to the repeating unit. This can decrease the required computational resources and enable better averaging for improved signal to noise.


The phenix.map_symmetry program uses the density at a set of randomly-chosen points in a cryo-EM map to identify symmetries, which are selected from a set of pre-defined symmetry types (e.g., point-group symmetry and helical symmetry). The tool then creates a file with the symmetry operations.

By default, phenix.map_symmetry assumes the principle axes of symmetry in a map are along x, y, and z and that the helical symmetry is along z. The user can specify a specific symmetry type or look for all elements in the database of 45 common symmetry elements and point groups.

How to use the phenix.map_symmetry: Click here

Common issues


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