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Gordon TollinRegents Professor Emeritus of Biochemistry and Molecular Biophysics Professor Emeritus of Chemistry gtollin@u.arizona.edu BioSciences West 453 Phone: (520) 621-3447 Fax: (520) 621-9288 |
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Education and Appointments
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Research Summary | |
| Mechanisms of Biological Electron Transfer and Energy Conversion Electron transfer processes play key roles in a wide variety of basic biological phenomena: e.g. respiration, photosynthesis, nitrogen fixation, steroid and DNA biogenesis, fatty acid and carbohydrate catabolism, etc. These reactions involve redox proteins consisting of one or more polypeptide chains, which bind cofactors such as metal ions (copper, iron-sulfur clusters) and metallo-organic (heme) or organic (flavin) molecules which function as electron or hydrogen carriers. Redox proteins may be soluble or membrane-associated, and electron transfer can occur via both inter- and intra-protein reactions. The primary goals of our research program are to elucidate the relationships between redox protein structure and the biochemical specificity, the rates and the mechanisms of these reactions, and to understand the role of lipid bilayer membranes in controlling and modulating redox protein properties. The tools which we use include transient-state kinetic methods such as stopped-flow and laser flash photolysis spectrophotometry, optical spectroscopic (including surface plasmon resonance) and electrochemical methods, site-directed mutagenesis and computer molecular graphics. Photoactive proteins mediate a large number of processes in which light energy is utilized for biological purposes (e.g. photosynthesis, vision, ion pumping, photomovement, etc.). We have been studying structure/function relations in one such protein, Photoactive Yellow Protein (PYP), which mediates the phototactic response in phototrophic halophilic bacteria, using time-resolved spectroscopy and site-specific mutagenesis. 
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