HT2: Processing
L2 (Lecture): Basics of X-ray data processing
Edward Lowe
Department of Biochemistry
University of Oxford
Oxford, UK
Images -> Spot finding -> indexing -> Space group -> Scaling & Merging -> Data quality assessment
The processing of diffraction image data is a fundamental step in the determination of structures by X-ray crystallography. In this lecture we will explore in detail the steps involved in extracting scaled structure factor amplitudes from diffraction images. This will include finding diffraction spots in the image, autoindexing the data, integration of intensities and the scaling and merging of data. We will also consider how the quality of diffraction data can be assessed and how data pathologies such as twinning and translational non-crystallographic symmetry can be identified. The DIALS software for processing diffraction data will be used for examples.
Recommended Reading:
The principles of data processing are well covered in the textbook:
Rupp, B. Biomolecular Crystallography: Principles, Practice, and Application to Structural Biology 2009. Garland Science. 809 pages
Specific References for DIALS:
Winter G. et al. (2018) DIALS: implementation and evaluation of a new integration package. Acta Crystallogr D Struct Biol 74, 85-97
Beilsten-Edmands J. et al. (2020) Scaling diffraction data in the DIALS software package: algorithms and new approaches for multi-crystal scaling. Acta Crystallogr D Struct Biol 76, 385-399