MAD data collection - current trends

The multiwavelength anomalous dispersion (MAD) method of protein structure determination is becoming a routine technique in protein crystallography, T he increased number of wavelength-tuneable synchrotron beamlines capable of performing challenging MAD experiments, coupled with the widespread availa bility of charge-coupled device (CCD) based X-ray detectors with fast read- out times have brought MAD structure determination to a new exciting level. Ultrafast MAD data collection is now possible and, with the widespread use of selenium in the form of selenomethionine for phase determination, the m ethod is growing in popularity. Recent developments in crystallographic sof tware are complementing the above advances, paving the way for rapid protei n structure determination. An overview of a typical MAD experiment is descr ibed, with emphasis on the rates and quality of data acquisition now achiev able at third-generation synchrotron sources.