Why Look At Electron Density Maps?
Examining the correspondence between the published model PDB file and the electron density map (EDM) provides much clearer insight into the uncertainties in the model than does merely examining the model itself (see also Quality assessment for molecular models). In addition to examining the entire map (2mFo-DFc) it is revealing to examine the difference map (mFo-DFc), which shows where the model fails to account for the map.
