During the past several years, remarkable progress has been made in solving the structures of high molecular weight proteins using X-ray crystallography and multidimensional nuclear magnetic resonance (NMR) spectroscopy. As the structures of more proteins are being routinely solved, there is a growing need to solve the structures of many of such proteins in complex with DNA. Although a plethora of techniques is now available to study DNA-protein interaction, none provides detailed structural information at the molecular level (1 ,2 ). DNA-protein interactions are important in gene regulation, recombination, repair, transcription, and translation, and understanding these interactions at the molecular level is of paramount importance, which in many cases are responsible for various abnormalities.
