A chemical interpretation of protein electron density maps in the worldwide protein data bank
Fig 9
The absolute scale of the density ratio for all structures in the PDB.
Panel A shows the density ratios vs. inverse of voxel volume plot indicates that there is a consistent 1:3 ratio. Panel B is the histogram of the multiplication of the x and y axes values from Panel A. They both show that the density ratio is not affected much by adding an estimated F000 term.