The major emphasis of work in this laboratory involves:

(1) the biochemical-genetic analysis of nitrogenase catalysis and
(2) 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 we are 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. Our 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.

Dolan, E., Johnson, D. (2009). Toward a holistic view of undergraduate research experiences: An exploratory study of impact on graduate / postdoctoral mentors. Journal of Science Education and Technology 18: 487-500.

Dos Santos, P. C., Smith, A. D., Frazzon, J., Cash, V. L., Johnson, M. K., and Dean D. R. (2004) Iron-Sulfur Cluster Assembly: NifU-DIRECTED ACTIVATION OF THE NITROGENASE Fe PROTEIN J. Biol. Chem. 279:19705-19711.   [Abstract]

Seefeldt, L. C., Dance, I. G., and Dean, D. R. (2004) Substrate Interactions with Nitrogenase: Fe versus Mo. Biochem. 43:1401-1409.   [Abstract]

Dos Santos, P., Dean, D. R., Hu, Y., and Ribbe, M. W. (2004) Formation and Insertion of Formation and Insertion of the Nitrogenase Iron-Molybdenum Cofactor. the Nitrogenase Iron-Molybdenum Cofactor. Chem. Reviews 104:1159-1173.   [Abstract]

Lee, H. I., Benton, P. M. C., Laryukhin, M., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2003) The Interstitial Atom of the Nitrogenase FeMo-Cofactor: ENDOR and ESEEM Show it is not an Exchangeable Nitrogen. J. Am. Chem. Soc. 125:5604-5605.   [Abstract]

Benton, P. M. C., Laryukhin, M., Mayer, S. M., Hoffman, B. M., Dean, D. R., and Seefeldt, L. C. (2003) Localization of a Substrate Binding Site on FeMo-Cofactor in Nitrogenase: Trapping Propargyl Alcohol with an Alpha-Substituted MoFe Protein. Biochem., in press.

Mayer, M. M., W. G. Niehaus, & D. R. Dean (2002) Reduction of short chain alkynes by a nitrogenase ?-70Ala-substituted MoFe protein. J. Chem. Soc. Dalton Trans. 2002: 802-807.   [Abstract]

Schmid, B., M. W. Ribbe, O. Einsle, M. Yoshida, L. M. Thomas, D. R. Dean, D. C. Rees, & B. K. Burgess (2002) Structure of a cofactor-deficient nitrogenase MoFe protein. Science 296:352-356. (Featured in the News and Views section of Science and also in the Science & Technology section of Chemical & Engineering News, April 15 issue).

Benton, P. M. C., S. M. Mayer, J. Shao, B. M. Hoffman, D. R. Dean, & L. C. Seefeldt (2001). Interaction of acetylene and cyanide with the resting state of nitrogenase ?-96-substituted MoFe proteins Biochemistry, 40:1534-1537.   [Abstract]

Frazzon, J. & D. R. Dean (2001) Feedback regulation of iron-sulfur cluster biosynthesis. Proc. Natl. Acad. Sci. USA 98:14751-14753.   [Abstract]