Beyond Mesh and Collect: small samples, room temperature experiments and time resolved crystallography using multiple crystals

The mesh and collect workflow developed at the ESRF is used to perform partial collects on a set of crystals mounted on the same support. After reconstruction of a diffraction quality map with DOZOR (Popov, unpublished) a small rotation wedge, usually 10°, is collected at each position. The partial datasets collected must then be merged to obtain a complete one. A correlation-coefficient based hierarchical cluster analysis program, ccCluster, has been developed to this scope. The program makes it easier for users to choose, the most isomorphous datasets that will be merged together to give good final statistics. Starting from this work, we applied those ideas to perform more kind of measurements. Time resolved experiments, experimental phasing and room temperature data collections can all benefit from the multi-crystals approach, provided that the isomorphism is good. As radiation damage is one of the main sources of non-isomorphism in macromolecular crystallography, a new strategy determination protocol has been developed. Along with the data collection methods, data processing is the main key to obtain good results. We  will present here different currently available strategies to deal with multi-crystal and serial crystallography data, along with ideas for the post-EBS data collection scenarios.