Density modification for macromolecular phase improvement

Density modification provides a simple and largely automatic tool for impro ving phase estimates for observed structure factors. The phase information arises from a combination of the known structure factor magnitudes, the cur rent phase estimates, and stereochemical information. The magnitudes, the c urrent phase estimates, and stereochemical information. The addition of the se phase information derived from theoretical sources renders new structure s amenable to solution, and reduces the effort required to solve other stru ctures. A diverse array of techniques which have been applied to the phase improvement problem are reviewed. (C) 1999 Published by Elsevier Science Lt d. All rights reserved.