Recent developments in classical density modification

Acta Crystallogr D Biol Crystallogr. 2010 Apr;66(Pt 4):470-8. doi: 10.1107/S090744490903947X. Epub 2010 Mar 24.


Classical density-modification techniques (as opposed to statistical approaches) offer a computationally cheap method for improving phase estimates in order to provide a good electron-density map for model building. The rise of statistical methods has lead to a shift in focus away from the classical approaches; as a result, some recent developments have not made their way into classical density-modification software. This paper describes the application of some recent techniques, including most importantly the use of prior phase information in the likelihood estimation of phase errors within a classical density-modification framework. The resulting software gives significantly better results than comparable classical methods, while remaining nearly two orders of magnitude faster than statistical methods.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anisotropy
  • Computer Simulation
  • Crystallography, X-Ray / methods*
  • Software Design*