The first experience of a protein crystallographer with the Oxford Diffraction Enhanced Ultra source and the Atlas CCD detector

J. Dohnálek^1,2, T. Kovaľ¹, M. Dušek¹

¹">Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, Praha 6, Czech Republic

²<aff><oid id="">Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovského nám. 2, Praha 6, <cny>Czech Republic</cny></aff>

dohnalek@fzu.cz

The Gemini PX Ultra diffractometer with Atlas CCD detector provides a new platform for protein crystallography experiments. The enhanced copper source of X-ray radiation together with the highly sensitive CCD detector with novel features is a sufficient solution for many diffraction experiments involving single crystals of biological macromolecules.

The original design of the diffractometer with focus on “small molecule” crystallography brings many options for protein diffraction experiments not available with standard setups for macromolecular crystallography such as the kappa goniometer, possibility of non-zero theta measurements (high resolution protein diffraction with large unit cells) and variability of data collection approaches together with built-in automated design of data collection strategy.

Introductory measurements and comparative studies regarding the performance of the CCD detector with high sensitivity, dynamic range and fast readout were performed with several protein samples. Diffraction data sets of high quality were collected, including those of the extracellular part of the human receptor CD69 and other study targets. This experimental setup offers a viable option for in-house diffraction experiments with protein samples. Interestingly, protein diffraction data with the total R_int < 0.03 up to the diffraction limit of 2.0 Å have been recorded and processed.

Acknowledgements.

The work was supported by the Czech Science Foundation, project No. 305/07/1073 and by the European commission, project LSHG-CT-2006-031220.