Sample screening and X-ray diffraction data collection for CHTSB occurs remotely using the Stanford Auto Mounter system (SAM) and the remote software tools developed by SSRL (Cohen et al., 2002; Soltis et al., 2008; McPhillips et al., 2002). Currently, screening in the laboratory takes place using manual mounting on a rotating anode X-ray generator with image plate detector.  SSRL is building a beamline emulator at HWI to incorporate the SAM system and the tools necessary to accomplish remote data collection in house. The floor plan of the system is shown in Figure 1.

The beamline emulator system consists of an existing rotating anode generator recently upgraded with Rigaku MaxFlux optics, a robot for sample handling, a motorized goniometer, optimized lighting and extensive video systems. This is paired with an image plate with a motorized crystal-to-detector distance. To all intents and purposes (with the exception of flux), the system will operate identically to the remote operation routinely carried out at SSRL.

This system will come on-line in the latter part of 2007. It will be used for crystal triage. Three SSRL cassettes will be used in the liquid nitrogen Dewar, one cassette empty with the other two holding samples for screening. Crystals that show good diffraction, i.e. clear single reflections no matter what resolution, will be moved from the screening cassette to the shipping cassette. Those that show no diffraction at all will be transferred to the shipping cassette to see if the increased flux available at the synchrotron can extract any diffraction information. Finally, those that show poor diffraction qualities, e.g. splitting, streaks, excessive mosaicity etc. will be returned to the screening cassette. The in-house system gives us several advantages; it adopts a standard mounting system so that we are completely compatible with the synchrotron at the diffraction stage (no extra crystal handling steps occur between laboratory and synchrotron screening), it provides rapid feedback to crystal optimization, and it makes the best use of limited synchrotron time.

References

Cohen, A. E., P. J., Miller, M. D., Deacon, A. M., and Phizackerley, R. P. (2002): An automated system to mount cryo-cooled protein crystals on a synchrotron beamline, using compact sample cassettes and a small-scale robot. J. Appl. Cryst. 35, 720-726.

McPhillips, T. M., McPhillips, S. E., Chiu, H. J., Cohen, A. E., Deacon, A. M., Ellis, P. J., Garman, E., Gonzales, A., Sauter, C., Phizackerley, R. P., Soltis, S. M., and Kuhn, P. (2002): Blu-Ice and the Distributed Control System: software for data acquisition and instrument control at macromolecular crystallography beamlines. J. Synchrotron Radiation 9, 401-406. [Pub Med]

S. M. Soltis, A. E. Cohen, A. Deacon, T. Eriksson, A. Gonzalez, S. McPhillips, H. Chui, P. Dunten, M. Hollenbeck, I. Mathews, M. Miller, P. Moorhead, R. P. Phizackerley, C. Smith, J. Song, H. van dem Bedem, P. Ellis, P. Kuhn, T. McPhillips, N. Sauter, K. Sharp, I. Tsyba and G. Wolf. (2008). New Paradigm for Macromolecular Crystallography Experiments at SSRL: Automated Crystal Screening and Remote Data Collection. Acta Crystallogr. D64, 1210-1221.