An optimal strategy for X-ray data collection on macromolecular crystals with position-sensitive detectors

X-ray data collection on macromolecular crystals is preferably done with minimum exposure time and high completeness. A Fortran procedure - DCS - has been written in the environment of the MADNES program to predict the completeness of data before the start of actual data collection. In addition, the program can check and refine the data-collection strategy and suggest optimal settings and rotation ranges for one or more crystals in different orientations that give highest completeness in minimum exposure time, thus extending the life of the crystal. The method has been tested on previously collected data as well as on new structures. Since the program has been in full use in this laboratory, the completeness of collected data has improved significantly.