The three-dimensional structure in solution of a monomeric form of the Cu(II)-Co(II) containing superoxide dismutase (SOD) will be determined by using multidimensional NMR spectroscopy. Previous biophysical studies have shown that residues Arg143 and Thr137, located close to the Cu(II) site, play an important role in the reaction catalyzed by the enzyme. Site-specific mutations at these two positions will be carried out, and the solution structure of these two SOD derivatives will also be determined. Through the detailed comparison and analysis of the changes induced in the structure and dynamics of the active site channel upon mutation, correlations will be established between structure and enzymatic function. Due to the paramagnetism of the protein modifications to the standard NMR methodologies as well as development of new ones will be required in order to acquire a complete sequence-specific signal assignment and thus successfully proceed to the solution structure determination of monomeric CuCoSOD and its mutants.