Optimizing data collection
for crystal
structure determination
using anomalous dispersion methods
Ana González
Stanford Synchrotron Radiation Laboratory
Multiwavelength Anomalous Dispersion (MAD) phasing is a widely used and successful method to solve macromolecular structures. The standard data collection strategy for MAD experiments consists in data collection at three wavelengths. While this strategy maximizes the phasing power available from the data, it can result in long experiments and/or high radiation doses absorbed by the sample.
Possible solutions to reduce the experiment time include data collection to low resolution, data collection at two or just one wavelengths and collecting fewer data at each wavelength. The results from a study analyzing the minimum amount of data required for phasing, suggest that a data collection of fairly complete set of unique reflections at two wavelengths maximizing the dispersive differences between wavelengths can be as fast as collecting all the data at a single wavelength, while providing better quality maps.