The Stanford Automated Mounter: Enabling High-Throughput Protein Crystal Screening at SSRL

The macromolecular crystallography experiment lends itself perfectly to high-throughput technologies. The initial steps including the expression, purification and crystallization of protein crystals, along with some of the later steps involving data processing and structure determination have all been automated to the point where some of the last remaining bottlenecks in the process have been crystal mounting, crystal screening and data collection. At the Stanford Synchrotron Radiation Laboratory (SSRL), a National User Facility which provides extremely brilliant X-ray photon beams for use in materials science, environmental science and structural biology research, the incorporation of advanced robotics has enabled crystals to be screened in a true high-throughput fashion, thus dramatically accelerating the final steps. Up to 288 frozen crystals can be mounted by the beamline robot (the Stanford Automated Mounter, or SAM) and screened for diffraction quality in a matter of hours without intervention. The best quality crystals can then be remounted for the collection of complete X-ray diffraction data sets. Furthermore, the entire screening and data collection experiment can be controlled from the experimenter's home laboratory by means of advanced software tools that enable network-based control of the highly automated beamlines.