The specific purpose of this proposal is to determine the three dimensional structure of cytochrome P450. Our broader research goals are directed at answering two specific questions: (1) How do electron transport enzymes catalyze the activation of 02 and H2O ligands, and (2) How are electrons transported between electron transport proteins? The primary tool to be used in these studies is protein x-ray crystallography though whenever necessary biochemical methods will be utilized to help answer questions raised by the x-ray structure. In addition to cytochrome P450 from pseudomonas putida which catalyzes the stereospecific hydroxylation of camphor, we are interested in two other Pseudomonas P450s which utilize a long chain alcohol, linalcol, and an aromatic molecule, paracymine. Structures of these enzymes and resulting comparative structural analyses will enable a detailed understanding regarding the question of substrate specificity of P450. The complete monoxygenase system consists of two additional electron transfer proteins, a flavo and an iron sulfur protein. Structures of these proteins will provide additional insights into how these proteins interact with one another to form intermolecular electron transfer complexes.