Chapter

Chapter 11.5 The use of partially recorded reflections for post refinement, scaling and averaging X-ray diffraction data

Crystallography of biological macromolecules

Second Online Edition (2012)

Part 11. Data processing

  1. C. G. van Beek,
  2. R. Bolotovsky,
  3. M. G. Rossmann

Published Online: 14 APR 2012

DOI: 10.1107/97809553602060000834

International Tables for Crystallography

International Tables for Crystallography

How to Cite

van Beek, C. G., Bolotovsky, R. and Rossmann, M. G. 2012. The use of partially recorded reflections for post refinement, scaling and averaging X-ray diffraction data. International Tables for Crystallography. F:11:11.5:296–303.

Author Information

  1. Department of Biological Sciences, Purdue University, West Lafayette, IN 47907–1392, USA

Publication History

  1. Published Online: 14 APR 2012

Abstract

Previous methods used for placing diffraction data recorded on a set of image frames onto a common scale have depended on finding scale factors that minimize the difference between scaled, fully recorded reflections. However, frozen crystals usually have mosaic spreads comparable to the oscillation angle, resulting in only very few, if any, fully recorded reflections on any one frame. Two methods are presented for solving this problem. The first depends on summing the components of a reflection on neighbouring frames; the second depends on calculating the degree of partiality (described in the Appendix) of each partial reflection. Problems of reflection selection for scaling and the use of post refinement for accurate determination of unit-cell parameters and crystal setting angles are discussed.

Keywords:

  • Hamilton, Rollett and Sparks method;
  • anisotropic mosaicity;
  • anomalous scattering;
  • averaging of reflection intensities;
  • mosaicity;
  • partiality model;
  • scaling