σ{sup 2}{sub R}, a reciprocal-space measure of the quality of macromolecular electron-density maps

Journal Article · Tue Jun 01 04:00:00 EDT 1999 · Acta Crystallographica. Section D: Biological Crystallography

DOI:https://doi.org/10.1107/S0907444999003583· OSTI ID:22347965

A reciprocal-space measure of the quality of macromolecular crystallographic phases based on the variance of the local roughness of the map is presented. It has previously been shown that the presence of distinct regions of solvent and protein in macromolecular crystals leads to a high value of the standard deviation of local r.m.s. electron density and that this can in turn be used as a reliable measure of the quality of macromolecular electron-density maps [Terwilliger & Berendzen (1999a ▶). Acta Cryst. D55, 501–505]. Here, it is demonstrated that a similar measure, θ{sub R}{sup 2}, the variance of the local roughness of the electron density, can be calculated in reciprocal space. The formulation is suitable for rapid evaluation of macromolecular crystallographic phases, for phase improvement and for ab initio phasing procedures.

• OSTI ID: 22347965
• Journal Information: Acta Crystallographica. Section D: Biological Crystallography, Journal Name: Acta Crystallographica. Section D: Biological Crystallography Journal Issue: Pt 6 Vol. 55; ISSN ABCRE6; ISSN 0907-4449
• Country of Publication: Denmark
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTALS
DENSITY
ELECTRON DENSITY
ELECTRONS
EVALUATION
PROTEINS
ROUGHNESS
SOLVENTS