The principal objective of this project is to define the binding site and nature of the conformational changes occurring in the lac-Repressor protein upon its interaction with operator DNA on the basis of data collected by nuclear magnetic resonance spectroscopy (NMR). The significance of these studies lies in the fact that a description of the structural basis for nucleic acid-protein interactions in sample genetic regulatory systems such as the lac-Repressor is a prerequisite for a better understanding of the fundamental mechanisms of genetic regulation in general.