Fred M. Hawkridge
 |
Professor
and associate dean |
Education
B.S., University of Georgia
Ph.D., University of Kentucky
Research interests
This research program broadly involves studies of the electron transfer and ligand binding reactions of heme proteins found in mammalian organisms. Of particular interest is the cytochrome c reductase, cytochrome c, cytochrome c oxidase and dioxygen sequence of oxidative phosphorylation. In the past we have studied samples that are either normally soluble in water (i.e., cytochrome c) or detergent solubilized (i.e., enzymes). Recently we have been using a combination of Langmuir-Blodgett procedures and self-assembly procedures to prepare mono- and bilayers on electrodes into which the enzymes are partitioned. At issue in this work is the direct communication of the enzymes with an electrode and providing a lipophilic, ordered membrane environment for the enzymes.
In another area of research we are studying the dynamics of dioxygen binding by myoglobin, the molecule in our muscles that stores oxygen for later use. An unexpected finding in studying the simple redox reactions of metcyanomyoglobin was a large shift in formal potential (ca. 0.4 V) and an increase in the rate of electron transfer by a factor of about 50. Combined optical absorption spectroscopy and electrochemical methods are being used in this work to try and understand these observations. An obvious parameter that changes between these ligated forms of myoglobin is the heme iron spin state. However, this does not seem to be the sole reason for these differences.
We also have been using circular dichroism and magnetically induced circular dichroism to probe conformational dynamics in the systems described above. Differences in reductive and oxidative electron transfer have been attributed to differences in conformational changes occurring during these reactions.
Selected publications
- F. M. Hawkridge and I. Taniguchi, “Electrochemistry of Heme Proteins,” in “The Porphyrin Handbook,” K. M. Kadish, K. M. Smith, and R. Guilard (Eds.) Academic Press, New York, Chapter 58, 2000, pp. 191-202. Review Article.
- M. C. Rhoten, J. D. Burgess, and F. M. Hawkridge, J. Electroanal. Chem., 534(2002) 143-150. “The Reaction of Cytochrome C from Different Species with Cytochrome c Oxidase Immobilized in an Electrode Supported Lipid Bilayer Membrane.”
- M. C. Rhoten, J M. Wilczek, and F. M. Hawkridge, J. Electroanal. Chem., 535(2002) 97-106. “The Reaction of Cytochrome c with Bovine and Bascillus stearothermophilus Cytochrome c Oxidase Immobilized in Electrode-Supported Lipid Bilayer Membranes.”
- J. D. Burgess and F. M. Hawkridge, “Direct Electron Transfer Reactions of Proteins and Enzymes at Electrodes,” in “Bioanalytical Electrochemistry,” A. Brajter-Toth and J. Q. Chambers (Eds.), Marcel Dekker, 2002, pp. 109-142.
- L. Su, J.B. Kelly, F.M. Hawkridge and M.C. Rhoten, “Characterization of Cyanide Binding to Cytochrome c Oxidase Immobilized in Electrode-Supported Lipid Bilayer Membranes,” J. Electroanal. Chem., 580 (2005) 241-248.
- K.L. Lewis, L. Su, F.M. Hawkridge, K.R. Ward and M.C. Rhoten, “Immobilization of Cytochrome c Oxidase into Electrode-Supported Lipid Bilayer Membranes for in vitro Cytochrome c Sensing,” IEEE Sensors, 6 (2006) 420-427.
