NMR Core Abstract The PCHPI NMR Core has four specific aims: 1) Screen recombinant proteins to evaluate their biophysical properties, structural integrity and determine their suitability for further structural determinations. 2) Screen HIV proteins for putative/proposed interactions with host proteins; 3) Carry out NMR mapping of interfaces; and 4) Determine solution structures of complexes, identified through screening. The Core will also carry out studies that are integrated into Project 6, in particular elucidation of the interactions between Vpr and DNA repair proteins, and will contribute on Projects 1 and 2 and the Technology Development Program 2. The NMR Core will work in an iterative fashion, with the Protein Core, facilitating the generation of well-folded, stable complexes for structure determination by NMR spectroscopy and/or X-ray crystallography.