Crystallography is a biophysical method to measure the structure of a protein in its crystallized form. After protein crystals are successfully produced (for more information please see Protein Purification and Crystallization), the protein structure can be recorded by shooting the crystals with radiation. When the radiation beam hits the crystal, a diffraction pattern can be monitored which is essential to model the complete structure of the protein inside the crystal at an atomic resolution.
XFel Crystallography
XFel Crystallography
We are using the femtosecond X-ray Free Electron Laser (XFel) worldwide to collect X-ray diffraction and emission spectra simultaneously. Our novel and unique sample delivery method, shown on the left, facilitates room temperature, time dependent data collection. The droplet on tape method (DOT) utilizes an acoustic droplet dispensor to create droplets of crystal slurries onto a kapton tape. The tape travels through our micro environment before traveling to the XFel beam. The micro environment can include laser illumination, gas saturation, or humidity changes. The droplet is timed with the pulse of the XFel. Therefore, this method minimizes waste and maximizes micro environment flexibility. For more information on this method, please check out Fuller et al 2017, Young et al 2016, Kern et al 2018 and Ibrahim et al 2020 (see publications).
We utilize our delivery system at XFel facilities to study biological systems. This unique method aids in simultaneous collection of X-ray diffraction (along the beam path) and spectroscopy (perpendicular to the beam). By collecting both data, we are able to correlate crystal structure with electronic information. By utilizing the high flux, time-resolved nature of the XFel, we can measure data from our biological samples without radiation damage seen at traditional synchrotron facilities. Our research focuses on metalloenzymes, such as PSI described here.
XFel
XFel
XFel crystallography gives us the chance to measure time-resolved and steady state protein structures under more physiological conditions namely under room temperature and without radiation damage.
For this approach we are using four XFel facilities worldwide which are LCLS (USA) , SwissFEL (Switzerland), PAL (Korea) and SACLA (Japan).
Synchrotron
Synchrotron
Synchrotron facilities are used in our group to conduct single-crystal x-ray experiments under room temperature and cryo conditions. We are closely working together with the Berkeley Center for Structural Biology and are users of ALS (USA), SSRL (USA) and diamond (UK).
Neutron diffraction
Neutron diffraction
Neutron diffraction, also called neutron scattering, is the third method in our group used to record protein structures. With this method we have the chance to measure nuclei of the atoms in our structure enabling to actually detect protons as well.
We are using the neutron scattering facility of ORNL (USA).
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