Beginners Guide to X-ray Data Processing
In general, the bottleneck in determining the structures of proteins using X-ray crystallography is obtaining the well-ordered protein crystals needed to produce high-resolution diffraction data. Often a great deal of time and resource goes into finding the optimal protein constructs and the screening of 1000’s of different crystallisation conditions needed to grow such crystals. It makes sense that after all that hard work that every effort is made to extract as much information as possible from the resulting X-ray diffraction images. The data processing of X-ray diffraction images is often carried out automatically at most synchrotrons these days. However manual data processing is still commonly required in particular with newly obtained crystals when there is still some uncertainty about the correct space group or when there are pathological issues such as twinning. It, therefore, pays even for non-experts to understand something of the different steps and procedures used to process X-ray diffraction data.
Example X-ray Diffraction Image
A valuable service has therefore been provided by the recent publication of a short but well-written beginners guide to X-ray data processing in the June issue of The Biochemist by Harry Powell from Imperial College London (Powell H.R., 2021). Harry is well known in the crystallography community for his work on creating a user-friendly GUI for Mosflm, one of the first popular X-ray data processing programs. The article clearly describes each of the steps involved in going from a collection of individual diffraction images to a final processed data file that can then be used for subsequent structure determination and modelling that are. Mention is also made of two of the X-ray data processing packages I spend a lot of my time using here Peak Proteins namely DIALS and XDS.
Example Image from data Processing Program DIALS
Armed with the knowledge from this brief introduction an interested party should not only be able to better understand how experimental X-ray data is treated but also gain a deeper appreciation of the work required to generate X-ray protein structures in general.
At Peak Proteins, we provide Crystallography and Structure Determination alongside Protein Expression and Protein Purification, and Protein Mass Spectrometry services. If you have any questions regarding any of our services then please contact us directly at info@peakproteins.com for more details.
