NMR spectroscopy has undergone a revolution in recent years with the advent of several new methods overcoming the problems of sensitivity and resolution. Recent developments in biotechnology have made it easier and economical to introduce 13C, 15N and 2H into proteins and nucleic acids. At the same time, there has been an explosion in the number of NMR experiments that utilize such isotope labeled samples. Thus, a combination of isotopic labeling and multidimensional, multinuclear NMR has opened up new avenues for structural studies of proteins, nucleic acids and their complexes....