Automated workflows for strategy computation and data collection at synchrotron beamlines

The Global Phasing workflow derives and executes experimental strategies for macromolecular crystallography, optimized in real time for the crystal symmetry and mounting orientation and the expected experimental resolution. By acquiring sweeps at multiple orientations, the workflow averages out the differences in Lorentz intensity enhancement and multiplicity to produce equally weighted merged reflections for processing. Values for various classes of parameters can be read from configuration files, submitted diffraction plans or user interaction, with optimal transmission settings derived from the beam flux density and the intended experimental resolution. The program can be executed in user-driven or unattended mode. Strategies are available for native or phasing experiments in either basic or advanced versions. The workflow has been shown to improve resolution, the number of unique reflections measured and average I/σ compared with a single-sweep experiment on equivalent crystals with the same total radiation dose. The workflow is a standalone program that could be interfaced to any beamline-control system, and is currently available through its integration with MXCuBE on a number of beamlines.