Protein Crystallography

1. Protein purification – The protein of interest is isolated in a pure form.
2. Crystallization – The protein is induced to form a regular crystal lattice (often the most challenging step).
3. X-ray diffraction – Crystals are bombarded with X-rays, which scatter based on the arrangement of atoms.
4. Data collection and analysis – The diffraction pattern is recorded and used to calculate an electron density map.
5. Model building and Structure Determination – A model of the protein structure is constructed to best fit the electron density data.

• Users can bring their purified sample to the facility and screen for suitable crystallisation conditions (several commercially available screens are available in 96-well format).
• Users will be trained in the use of the liquid handling robot Mosquito.
• Support with condition optimisation, screening and checking for potential hits.
• Assistance with Cryo-protection and freezing of crystals.
• Crystals are shipped to Diamond Light Source, the national synchrotron facility in Didcot, Oxford for data collection.
• Experienced users can remotely collect their own data, otherwise support can be provided.
• Help with different crystallography software suites such as CCP4 and Phenix, and visualisation software such as COOT and PyMOL. 

Screening for hundreds of conditions can be carried out with as little as ~100 ul of purified protein at the appropriate concentration, however in most cases ~250 ul is recommended.