A variety of spectroscopic, physical and kinetic methods are used to characterize the mechanism of electron transfer in important biological systems. Emphasis is placed on the enzyme complexes of the mitochondrial electron transfer chain and on the metalloflavoprotein, xanthine oxidase. Principal long-term objectives are to define the structural and dynamic attributes of the mitochondrial complexes in sufficient detail that hypotheses for the mechanisms of energy conservation can be rigorously evaluated. The principal techniques, optical, magnetic circular dichroism and electron paramagnetic resonance spectroscopy, will be employed in both equilibrium and kinetic experiments; nuclear magnetic resonance and Raman spectroscopy will also be utilized. Major issues to be addressed include: (a) The structural and kinetic properties of the components of cytochrome oxidase and the nature of the oxygen intermediates. (b) The mechanism of electron transfer in yeast Complex III and the validity of the Q-cycle. (c) Ligands of the heme centers in Complex III. (d) The nature of the iron-sulfur centers in Complexes II and III. (e) The mechanism of electron transfer in Complex II. (f) Analyses of the fundamentals of steady state kinetics in enzymes with non-interacting reaction sites for each substrate.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM021337-11
Application #
3270407
Study Section
Metallobiochemistry Study Section (BMT)
Project Start
1979-06-01
Project End
1989-05-31
Budget Start
1985-06-01
Budget End
1986-05-31
Support Year
11
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Rice University
Department
Type
Schools of Arts and Sciences
DUNS #
050299031
City
Houston
State
TX
Country
United States
Zip Code
77005
Tsai, Ah-lim; Wu, Gang; Rogge, Corina E et al. (2011) Structural comparisons of arachidonic acid-induced radicals formed by prostaglandin H synthase-1 and -2. J Inorg Biochem 105:366-74
Fabian, M; Palmer, G (1999) Redox state of peroxy and ferryl intermediates in cytochrome c oxidase catalysis. Biochemistry 38:6270-5
Tsai, A l; Wu, G; Palmer, G et al. (1999) Rapid kinetics of tyrosyl radical formation and heme redox state changes in prostaglandin H synthase-1 and -2. J Biol Chem 274:21695-700
Sakamoto, H; Omata, Y; Palmer, G et al. (1999) Ferric alpha-hydroxyheme bound to heme oxygenase can be converted to verdoheme by dioxygen in the absence of added reducing equivalents. J Biol Chem 274:18196-200
Fabian, M; Palmer, G (1998) Hydrogen peroxide is not released following reaction of cyanide with several catalytically important derivatives of cytochrome c oxidase. FEBS Lett 422:1-4
Tsai, A l; Palmer, G; Xiao, G et al. (1998) Structural characterization of arachidonyl radicals formed by prostaglandin H synthase-2 and prostaglandin H synthase-1 reconstituted with mangano protoporphyrin IX. J Biol Chem 273:3888-94
Tsai, A L; Berka, V; Kulmacz, R J et al. (1998) An improved sample packing device for rapid freeze-trap electron paramagnetic resonance spectroscopy kinetic measurements. Anal Biochem 264:165-71
Berka, V; Palmer, G; Chen, P F et al. (1998) Effects of various imidazole ligands on heme conformation in endothelial nitric oxide synthase. Biochemistry 37:6136-44
Liao, G L; Palmer, G (1998) Diazene--a not so innocent ligand for the binuclear center of cytochrome c oxidase. Biochemistry 37:15583-92
Liao, G L; Palmer, G (1996) The reduced minus oxidized difference spectra of cytochromes a and a3. Biochim Biophys Acta 1274:109-11

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