General objectives are the use of x-ray crystallography to determine the three-dimensional structures of proteins and the interpretation of those structures. The specific projects are as follows: Completion of the native structure of bovine Cu, Zn superoxide dismutase, including some further cycles of refinement, fitting by computer graphics, and comparison of the four crystallographically-independent subunits. Solution of heavy-atom derivatives and processing of screened-precesion film data in order to obtain first a low-resolution and later a high-resolution structure of the human liver Mn superoxide dismutase (space group P6122, a equals 242A, c equals 81.3A, one dimer per asymmetric unit). Collection of slow-rotation film data, heavy-atom derivative search, and proceeding toward a structure of chicken liver sulfite oxidase (space group R3, a equals 158.2A, c equals 138.3A, one dimer per asymmetric unit). Determining the structure of the Root-effect hemoglobin from spot, starting with phases from our current rotation function results. Search for further generalizations about protein structure, including the use of those generalizations in interpreting low-resolution x-ray data, and the modification of our schematic drawings to serve specific research and teaching needs.