A high-throughput structural biology/proteomics beamline at the SRS on a new multipole wiggler

The North West Structural Genomics Centre's beamline, MAD10, at the SRS receives the central part of the radiation fan (0.5 mrad vertically, 4 mrad horizontally) produced by a new 2.46 T ten‐pole wiggler. The optical arrangement of the beamline consists of a Rh‐coated collimating Si mirror, a fixed‐exit‐beam double‐crystal monochromator with sagittal bending for horizontal focusing and a second Rh‐coated Si mirror for vertical focusing. The double‐crystal Si (111) monochromator allows data collection in the 5–13.5 keV photon energy range with rapid (subsecond) tunability and high energy resolution. The monochromatic beam is optimized through a 200 µm collimator. The beamline end station has been designed around a Mar desktop beamline with high‐throughput cryogenic sample changer, Mar225 CCD detector, liquid‐N2 autofill system and an ORTEC C‐TRAIN‐04 energy‐resolving high‐count‐rate X‐ray fluorescence detector. The instrument is optimized for MAD/SAD applications in protein crystallography with the additional mode of operation of online single‐crystal EXAFS studies on the same crystals. Thus, screening of metals/Se in the crystal can be performed quickly prior to MAD/SAD data collection by exciting the crystal with X‐rays of appropriate energy and recording an energy‐dispersive fluorescence spectrum. In addition, this experimental set‐up allows for parallel XAFS measurements on the same crystal to monitor `radiation‐induced' changes, if any, in e.g. the redox state of metal centres to be detected for a `metallic' functional group during crystallographic data collection. Moreover, careful minimization of the thickness of the Be window maximizes the intensity performance for the 2.0–2.5 Å softer wavelength range. This range also covers the K‐edges of a number of important 3d transition metals as well as the L‐edges of xenon and iodine and enhanced sulfur f ′′.