MS01-P03 Serial synchrotron crystallography at EMBL PETRA III beamline P14 Johanna Hakanpää (European Molecular Biology Laboratory, Hamburg, Germany) Gleb Bourenkov (European Molecular Biology Laboratory, Hamburg, Germany) Ivars Karpics (European Molecular Biology Laboratory, Hamburg, Germany) Guillaume Pompidor (European Molecular Biology Laboratory, Hamburg, Germany) Isabel Bento (European Molecular Biology Laboratory, Hamburg, Germany) Thomas Schneider (European Molecular Biology Laboratory, Hamburg , Germany)email: johanna@embl-hamburg.deSerial synchrotron crystallography (SSX) combines X-ray images taken from randomly oriented crystals, passed through the beam using diverse delivery methods, into a single dataset. The method requires a high-brilliance synchrotron source with a beam size similar to the sample size, an appropriate sample delivery method, a detector with sufficient frame rate and a data processing pipeline. SSX can act as a pre-screening method for XFEL experiments or a stand-alone experiment when crystal growth to larger size cannot be achieved, e.g. in vivo grown crystals. Proof of principle experiments (1) have shown the feasibility of the method.
 
Our SSX setup at the EMBL beamline P14 (PETRA III, DESY Hamburg) utilizes the tools of conventional crystallography, minimizing setup time and sample consumption. In situ experiments can be done in CrystalDirectTM plates, also in meso. Cryo-samples are mounted in loops or harvested from plates with the CrystalDirectTM Harvester. Generally, the sample size is a few microns. Data collection runs as series of helical line scans, typically a dataset is collected in a few minutes, depending on the size of the region of interest. Progression of the data collection is monitored throughout the experiment as on-the-fly calculated heat map, displaying the diffraction scores as estimated by program DOZOR (2).  
 
The acquired diffraction images are sorted and bunched into sub datasets according to the DOZOR score. The sub datasets are processed in parallel as small rotation datasets with XDS and scaled using XSCALE. We have demonstrated the feasibility of the pipeline using 5-micron lysozyme crystals as test objects. Using an Eiger4M detector, a data set of 65120 images was collected at P14 in 3 minutes as an in situ experiment in a CrystalDirectTM plate.  About 2000 sub datasets, each containing 5-10 diffraction images, were integrated and scaled to yield complete data to 1.7 Å resolution. The structure could be solved by molecular replacement and electron density maps were of good quality.
 
We have established protocols for sample delivery, data collection and processing, making the pipeline feasible to use without previous experience in serial crystallography. Alternating between serial and conventional data collections is user controlled. Beamtime for experiments at P14 can be applied for through the EMBL user program at https://smis.embl-hamburg.de.
References:

1) Gati G., Bourenkov G., Klinge M., Rehders D., Stellato F., Oberthür D., Yefanov O., Sommer B.P., Mogk S., Duszenko M., Betzel C., Schneider T.R. , Chapman H.N., Redeckec L. (2014) IUCr J. 1 87-94

2) Popov, A. N. & Bourenkov, G. P. (2015). DOZOR. European Synchrotron Radiation Facility, Grenoble, France

Keywords: serial synchrotron crystallography