Villigen, 6 Sep 2016. The MX group at the Swiss Light Source has just published a paper that describes the best way of collecting macromolecular diffraction data with EIGER. In collaborative work with scientists at DECTRIS, Meitian Wang and colleagues show that measuring with EIGER leads to higher-quality data than with PILATUS, as long as the data are finely enough sliced in phi. Whereas an oscillation angle of 1/2 the XDS mosaicity was recommended for PILATUS, EIGER data benefit from collection at 1/10 the XDS mosaicity. Regardless of phi-slicing, the smaller pixel size of EIGER further increases data quality in the highest resolution shells because less background is measured with weak reflections.
The paper, published in the September 2016 issue of Acta Crystallographica Section D and freely available under a Creative Commons Attribution License, marks another milestone in the progress of macromolecular crystallography. In 2006, PILATUS introduced Hybrid Photon Counting and revolutionized data collection, both in terms of speed and in terms of quality. Now, ten years later, EIGER takes science further yet. Ultrafine phi-slicing provides data of unprecedented quality, collected even more quickly than before. Like those researchers that recently solved structures of Zika virus envelope protein in complex with a neutralizing antibody and of CRISPR-Cpf1 in complex with guide RNA and target DNA from EIGER data, crystallographers will determine structures from ever more challenging crystals and increase our understanding of complex biological processes in health and disease.
Picture caption: Smaller pixels of EIGER lead to increased data quality. When EIGER data are binned fourfold, data quality as indicated by Rmeas decreases, in particular for higher-resolution information.