Hongliang Xu and Herbert A. Hauptman
Hauptman-Woodward Medical Research Institute & Department of
Structural Biology
SUNY at Buffalo, 73 High Street, Buffalo, NY
14203-1196
Abstract:
The phase problem of X-ray
crystallography can be formulated as a problem in constrained global
minimization. The minimal function and its minimal principle employed in
the traditional Shake-and-Bake algorithm rely on the
probabilistic estimates of the cosines of the structure invariants. A
novel statistical approach to the phase problem, which utilizes
statistical properties of the structure invariants, has been recently
proposed. The statistical minimal function and its minimal principle are
formulated, and the corresponding statistical Shake-and-Bake
algorithm and its associated statistical parameter-shift procedure are
proposed and tested.
The test results, based on 19 selenium-atom substructures spanning different sizes, resolutions and space groups, show that the statistical approach to the phase problem is a simple, reliable, less computationally intensive and more efficient procedure for phase determination in X-ray crystallography. The Statistical Shake-and Bake method has been incorporated into the latest versions of computer programs SnB and BnP.
This research was supported by NIH grant EB002057.
2008 Run
Nov 19th - Dec 22nd
