Overview of the tunable beamlines for protein crystallography at the EMBL Hamburg Outstation; an analysis of current and future usage and developments.

The EMBL Hamburg Outstation currently operates two tunable protein crystallography beamlines suitable for single and multiple anomalous diffraction (SAD/MAD) experiments. The first beamline, designated X31, is located on a bending magnet of the DORIS III storage ring whereas the second beamline, BW7A, is positioned at a multipole wiggler at the same storage ring. X31 is equipped with an energy stabilization device to ensure constant wavelength during longer data-collection periods. The in-house built crystallographic end-station is now equipped with a Mar345 imaging-plate scanner as a detector. The wiggler beamline BW7A features a novel sagitally focusing monochromator. The end-station used here has also been developed and built in-house. The beamline is currently operated with a Mar 165 CCD detector. In this paper the hardware and software developments of the last years will be summarized and the outlook for substantial upgrades will be given. The future plans include the design and construction of a third tunable beamline, designated X12, for protein crystallography. The development of automated beamlines for protein crystallography is of particular importance with respect to structural genomics initiatives. The analysis of the projects of the last years shows the wide range of anomalous scatterer used on the tunable beamlines thus demonstrating the need of a wide range of accessible energies and fast and reliable energy changes.