DESIGN: a guide to protein crystallization experiments.

Existing guidelines for crystallizing proteins generally require substantial amounts of protein and scarce laboratory resources. To address this problem we have developed the program DESIGN, which, suited to daily laboratory usage, utilizes statistics when screening variables of crystallization. The program DESIGN is described in considerable detail and examples of its outcome and capabilities are shown. In addition, a new scoring scale for crystallization trials is described. It is expected that the use of such an approach may provide additional constraints toward crystallizing the protein, even if the conditions applied are not successful.