Electron Density

Calculating Electron Density
After collection of diffraction data, the data must be integrated and scaled. This is usually done with HKL 2000, StructureStudio, or XDS.

The data must then be phased using a closely related protein structure, isomorphous replacement using a heavy atom derivative(s), or with tunable wavelengths at a synchrotron (MAD). The result of these techniques is the production of an electron density map that is used to fit as perfectly as possible all of the amino acid residues in the protein structure.

The programs mentioned above are available for use in the Structural Biology Core Labs that house the X-ray Generation, and X-ray Detection Equipment.

Once electron density is obtained one uses structural biology building programs, followed by refinement programs, in an iterative fashion to build into the density to obtain the best fit of the structure to the data.