W0037

Crystallization of Protein-DNA Complexes. Ehmke Pohl, European Molecular Biology Laboratory, Notkestr. 85, 22603 Hamburg. Germany.

Over the last two decades a large number of protein-DNA complexes have been successfully crystallized and the structures of such complexes have been determined to high resolution. Nevertheless, the crystallization of protein-DNA complexes often remains a formidable challenge. The sequence and length of the oligionucleotide used in the crystallization experiments have a strong influence on the crystallizibility and thus add important new parameters to the crystallization problem. So far, no method has been developed that predicts the optimal length of the DNA oligonucleotide reliably. However, with several hundred complexes crystallized by many groups we have learned that certain classes of precipitating agents such as low-molecular weight polyethyleneglycols and glycerol as well some additives such as polyamines, have often yielded crystal suitable for diffraction experiments. This led to the development of several tailor-made crystallization screening kits that are now available. In this lecture we will look at basic concepts of protein-DNA crystallization. The talk will include ideas ranging from the preparation and purification of the two components to strategies for the evaluation and optimization of the initial experiments.