The VISDEM method improves the visualization of density maps by using general
statistical information about proteins for the sharpening process. In particular, the packing
density of atoms is highly similar between different proteins, which allows for building a
pseudo-atomic model to approximate the true mass distribution. From this model the radial
structure factor and density value histogram are estimated and applied as constraints to
the 3D reconstruction in reciprocal- and real-space, respectively.
Real-space model refinement with DireX
This video introduces the real-space refinement program DireX, which has been developed to refine protein structures against low-resolution density maps from Cryo-EM or X-ray crystallography.