The major emphasis of work in Dr. Dean's laboratory involves:
- the biochemical-genetic analysis of nitrogenase catalysis and
- the molecular mechanisms of metallocluster formation.
Nitrogenase is the catalytic component of biological nitrogen fixation. It is a complex, two-component metalloenzyme that couples MgATP hydrolysis to the reduction of dinitrogen. In one project Dr. Dean is dissecting the inter- and intramolecular pathways involved in substrate reduction by using molecular genetic techniques developed in this laboratory to place known amino acid substitutions within the component proteins. Through the biochemical and biophysical characterization of such altered proteins we are gaining insight into how the enzyme complex works. A second project is related to understanding how the metalloclusters required for nitrogenase activity are assembled and inserted into the nitrogenase component proteins. The work has involved using recombinant DNA techniques to hyperproduce polypeptides involved in the process together with the development of in vitro metallocluster assembly pathways. Dr. Dean's laboratory enjoys a close association with the Metalloenzyme Center at the University of Georgia and there are currently active collaborations between this laboratory and colleagues at Wisconsin, Northwestern, Purdue, and Minnesota. The laboratory is housed in the new Fralin Biotechnology Center and is equipped with state of the art facilities for fermentation, anaerobic purification and handling of oxygen sensitive proteins, recombinant DNA techniques, and computer-assisted molecular modelling of three-dimensional structures.