Iron-sulfur clusters containing a Fe2(mu2-S)2 core ([2Fe-2S] clusters) are one of the most ubiquitous electron carriers in nature and are integral components of Complex I, II, and III of the mitochondrial respiratory chain. Recent studies have also implicated the involvement of (2Fe-2S] clusters in iron-sulfur cluster assembly, iron insertion into porphyrin to form hemes, the synthesis of biotin from dethiobiotin, proton translocation, regulatory processes in response to oxidative stress and dehydratase reactions, although the precise role of the [2Fe-2S] clusters in these important biological processes has yet to be fully defined. The long-term goal of this research is a detailed understanding at the molecular level of the physicochemical properties of biological (2Fe-2S] centers with particular emphasis on the factors determining midpoint potential and the origin of their apparent functional diversity. Ultimately this will lead to enhanced understanding of the origin of human protoporphyria and diseases associated with inhibition of the respiratory chain enzymes. The approach involves using biophysical spectroscopic techniques, electron paramagnetic resonance, UV/visible/near-IR absorption, circular dichroism and magnetically induced circular dichroism, and resonance Raman, to investigate the electronic, magnetic and structural properties of [2Fe-2S] centers in a wide range of native and mutated enzymes and proteins. These include human and cyanobacterial ferredoxins, human ferrochelatase, spinach dihydroxyacid dehydratase, Escherichia coil biotin synthase, the Azotobacter vinelandii nifU gene product. In addition, enzymes and proteins extracted from or closely related to Complex I, II and III of the mitochondrial respiratory chain will be investigated, i.e. individual subunits of Paracoccus denitrificans NADH dehydrogenase, Escherichia coli fumarate reductase and a soluble Rieske protein fragment isolated from bovine heart mitochondria.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM051962-04
Application #
2608963
Study Section
Physical Biochemistry Study Section (PB)
Project Start
1994-12-01
Project End
1999-05-31
Budget Start
1997-12-01
Budget End
1999-05-31
Support Year
4
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Georgia
Department
Chemistry
Type
Other Domestic Higher Education
DUNS #
City
Athens
State
GA
Country
United States
Zip Code
30602
Agar, J N; Yuvaniyama, P; Jack, R F et al. (2000) Modular organization and identification of a mononuclear iron-binding site within the NifU protein. J Biol Inorg Chem 5:167-77
Agar, J N; Krebs, C; Frazzon, J et al. (2000) IscU as a scaffold for iron-sulfur cluster biosynthesis: sequential assembly of [2Fe-2S] and [4Fe-4S] clusters in IscU. Biochemistry 39:7856-62
Yuvaniyama, P; Agar, J N; Cash, V L et al. (2000) NifS-directed assembly of a transient [2Fe-2S] cluster within the NifU protein. Proc Natl Acad Sci U S A 97:599-604
Dhawan, I K; Shelver, D; Thorsteinsson, M V et al. (1999) Probing the heme axial ligation in the CO-sensing CooA protein with magnetic circular dichroism spectroscopy. Biochemistry 38:12805-13
Lou, J; Moshiri, F; Johnson, M K et al. (1999) Mutagenesis studies of the FeSII protein of Azotobacter vinelandii: roles of histidine and lysine residues in the protection of nitrogenase from oxygen damage. Biochemistry 38:5563-71
Kooter, I M; Koehler, B P; Moguilevsky, N et al. (1999) The Met243 sulfonium ion linkage is responsible for the anomalous magnetic circular dichroism and optical spectral properties of myeloperoxidase. J Biol Inorg Chem 4:684-91
Johnson, M K (1998) Iron-sulfur proteins: new roles for old clusters. Curr Opin Chem Biol 2:173-81
Goodwin, P J; Agar, J N; Roll, J T et al. (1998) The Azotobacter vinelandii NifEN complex contains two identical [4Fe-4S] clusters. Biochemistry 37:10420-8
Golinelli, M P; Chatelet, C; Duin, E C et al. (1998) Extensive ligand rearrangements around the [2Fe-2S] cluster of Clostridium pasteurianum ferredoxin. Biochemistry 37:10429-37
Staples, C R; Gaymard, E; Stritt-Etter, A L et al. (1998) Role of the [Fe4S4] cluster in mediating disulfide reduction in spinach ferredoxin:thioredoxin reductase. Biochemistry 37:4612-20

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