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Ralf W Grosse-Kunstleve

Publications and source records attributed to Ralf W Grosse-Kunstleve.

7 recordsLinked to original sources
PubMed2007

Substructure determination in isomorphous replacement and anomalous diffraction experiments.

The determination of the substructure of heavy atoms or anomalous scatterers is a central step in experimental-phasing procedures. We give an overview of commonly used methods for substructure determination, including estimation of substructure structure factors, Patterson methods, direct methods, dual-space recycling procedures, and methods for substructure refinement and completion. This chapter also includes an annotated list of available program packages.

Algorithms↗
PubMed2005

A robust bulk-solvent correction and anisotropic scaling procedure.

A reliable method for the determination of bulk-solvent model parameters and an overall anisotropic scale factor is of increasing importance as structure determination becomes more automated. Current protocols require the manual inspection of refinement results in order to detect errors in the calculation of these parameters. Here, a robust method for determining bulk-solvent and anisotropic scaling parameters in macromolecular refinement is described. The implementation of a maximum-likelihood target function for determining the same parameters is also discussed. The formulas and corresponding derivatives of the likelihood function with respect to the solvent parameters and the components of anisotropic scale matrix are presented. These algorithms are implemented in the CCTBX bulk-solvent correction and scaling module.

Algorithms↗
PubMed2005

Likelihood-enhanced fast translation functions.

This paper is a companion to a recent paper on fast rotation functions [Storoni et al. (2004), Acta Cryst. D60, 432-438], which showed how a Taylor-series expansion of the maximum-likelihood rotation function leads to improved likelihood-enhanced fast rotation functions. In a similar manner, it is shown here how linear and quadratic Taylor-series expansions and least-squares approximations of the maximum-likelihood translation function lead to likelihood-enhanced translation functions, which can be calculated by FFT and which are more sensitive to the correct translation than the traditional correlation-coefficient fast translation function. These likelihood-enhanced translation targets for molecular-replacement searches have been implemented in the program Phaser using the Computational Crystallography Toolbox (cctbx).

Bacterial Proteins↗
PubMed2003

Recent developments in the PHENIX software for automated crystallographic structure determination.

A new software system called PHENIX (Python-based Hierarchical ENvironment for Integrated Xtallography) is being developed for the automation of crystallographic structure solution. This will provide the necessary algorithms to proceed from reduced intensity data to a refined molecular model, and facilitate structure solution for both the novice and expert crystallographer. Here, the features of PHENIXare reviewed and the recent advances in infrastructure and algorithms are briefly described.

Algorithms↗
PubMed2002

PHENIX: building new software for automated crystallographic structure determination.

Structural genomics seeks to expand rapidly the number of protein structures in order to extract the maximum amount of information from genomic sequence databases. The advent of several large-scale projects worldwide leads to many new challenges in the field of crystallographic macromolecular structure determination. A novel software package called PHENIX (Python-based Hierarchical ENvironment for Integrated Xtallography) is therefore being developed. This new software will provide the necessary algorithms to proceed from reduced intensity data to a refined molecular model and to facilitate structure solution for both the novice and expert crystallographer.

Algorithms↗