Difference Maps

and

Isolating Ligands from Ribosome Reconstructions

Differences between volumes can be assessed by subtracting one volume from the other; the result is a difference map. Such differences provide one way to identify or isolate small masses in 3D reconstructions. The statistics of the volumes may be used to determine the significance of 3-dimensional features (see pages 252-254 in Three-Dimensional Electron Microscopy of Macromolecular Assemblies by J. Frank).

Before subtracting volumes, make sure they are properly aligned.


Source: techs/diffmaps/index.html     Page updated: 09/15/06