HOLOGRAPHIC METHODS IN X-RAY CRYSTALLOGRAPHY .5. MULTIPLE ISOMORPHOUSREPLACEMENT, MULTIPLE ANOMALOUS-DISPERSION AND NON-CRYSTALLOGRAPHIC SYMMETRY

Citation
A. Szoke et al., HOLOGRAPHIC METHODS IN X-RAY CRYSTALLOGRAPHY .5. MULTIPLE ISOMORPHOUSREPLACEMENT, MULTIPLE ANOMALOUS-DISPERSION AND NON-CRYSTALLOGRAPHIC SYMMETRY, Acta crystallographica. Section A, Foundations of crystallography, 53, 1997, pp. 291-313
Citations number
36
Categorie Soggetti
Crystallography
ISSN journal
01087673
Volume
53
Year of publication
1997
Part
3
Pages
291 - 313
Database
ISI
SICI code
0108-7673(1997)53:<291:HMIXC.>2.0.ZU;2-C
Abstract
The holographic method for the recovery of the electron density of mac romolecules is based on the expansion of the electron density into Gau ssian basis functions. The technique makes consistent use of real- and reciprocal-space information to produce electron-density maps. It enf orces positivity of the recovered electron density and makes effective use of previously known information about the electron density, such as knowledge of a solvent region or knowledge of a partial structure. In this paper, we summarize the theory underlying the holographic meth od, and describe how we extend the range of information that can be us ed by the method to include information from multiple-isomorphous-repl acement (MLR) data, multiple-anomalous-dispersion (MAD) data and knowl edge of non-crystallographic symmetry. The convergence properties and the limiting accuracy of the method are discussed. Its power for synth etic problems is demonstrated and the method is applied to experimenta lly measured MIR data from kinesin, a motor protein domain that has re cently been solved. Appendix A gives a detailed description of the alg orithms and the equations used in EDEN, the computer program that impl ements the holographic method.