Chapter 11: Crystallization of Protein–DNA Complexes
Determining the crystal structure of a protein–DNA complex can provide a wealth of information regarding protein function and mechanism. The foundation for all successful X-ray structure determination is the ability to produce diffraction-quality crystals. Crystallization of protein–DNA complexes often presents unique challenges because of the additional parameters involved. This chapter will outline many of those challenges, including choice of DNA and formation of a stable protein–DNA complex and provide guidance in preparing for crystallization experiments. Additionally, techniques for oligonucleotide purification, sample preparation, and crystallization methods are provided. Careful thought and initial analysis of the protein–DNA complex prior to crystallization experiments followed by optimization of crystallization parameters can greatly increase the likelihood of producing well-diffracting crystals.