Protein crystallography plays a central role in the advances of biochemical research. This application proposes to set up a state-of-the-art laboratory based X-ray data collection system consisting of an area detector and a rotating anode. The majority of the participants are at the Medical College of Wisconsin, three from the University of Wisconsin-Milwaukee, one member each from the University of Wisconsin-Parkside and the University of Texas Health Science Center at San Antonio. They collaborate on a number of projects of fundamental biomedical importance including: 1) structure and mechanism of acyl-CoA dehydrogenases in fatty acid oxidation, 2) structure of a blue nitrite reductase, 3) mechanism of methyl transfers. in acetyl-CoA synthesis, 4) elucidation of the structural basis for hydroxymethylglutaryl-CoA lyase deficiencies, 5) structure-function studies on a regulated kinase, 6) ATP, ubiquitin-dependent proteolysis, 7) a cellular vaccine against Pseudomonas aeruginosa, 8) structure-function studies on the microsomal flavoprotein, NADPH-cytochrome P450 reductase, 9) structural study of EnvZ, an inner membrane sensor protein in E.coli., and 10) structural studies of a nonamer binding protein in immunoglobulin gene recombination. This facility will allow data to be collected in house at the Medical College of Wisconsin, at a high rate and permits us to expedite the progress and broaden the scope of above projects.