The oxidation and reduction of various substrates in living organisms are of fundamental importance to life sustaining processes. Multi-electron transfer processes, although less frequent in nature are of equally great importance. Included among the latter are: the 6e-reduction of N2 to ammonia in nitrogenase, the 6e-reduction of sulfite to sulfide and of nitrite to ammonia in sulfite and nitrite reductases respective And the 4e- oxidation of 2H20 to O2 in photosynthesis. This proposal is concerned with the synthesis and study of synthetic analogs for a) metalloenzymes involved in multi-electron reduction and b) the non-porphyrin, non-Fe/S, iron centers active in oxidation processes. Specifically,: the synthesis, structures, spectroscopic properties and reactivitys of Fe/M/S (M=Mo,V) proposal. The Fe/M/S clusters are expected to sere as synthetic analogs for the Fe/M/S centers in the nitrogenases and alternate nitrogenases that contain vanadium or iron in place of molybdenum. The new types of Fe/S clusters that will be synthesized are designed as models for the P- clusters of nitrogenase. Superamolecular assemblies with attended Fe/S clusters containing pi acceptor ligands will be synthesized., and their possible function in the bimetallic activation and catalytic reduction of dinitrogen will be investigated. Multi-nuclear, mixed-ligand, carboxylate-catecholate complexes of first row elements will be studied as structure and reactivity models for the active sites in enzymes that catalyze the multi-electron oxidation of various substrates. The function of the catecholate ligands in these compounds, as storage sites of oxidizing equivalents, will be determined.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM033080-19A1
Application #
6468312
Study Section
Metallobiochemistry Study Section (BMT)
Program Officer
Preusch, Peter C
Project Start
1983-07-01
Project End
2006-03-31
Budget Start
2002-04-01
Budget End
2003-03-31
Support Year
19
Fiscal Year
2002
Total Cost
$327,000
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Lacal Romero, Jesus; Shen, Zhouxin; Baumgardner, Kimberly et al. (2018) The Dictyostelium GSK3 kinase GlkA coordinates signal relay and chemotaxis in response to growth conditions. Dev Biol 435:56-72
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Koutmos, Markos; Coucouvanis, Dimitri (2005) Metal clusters as ligands: substitution of Fe ions in Fe/Mo/S clusters by thiophilic Cu(I) ions to give clusters with [Cu4Mo2Fe2S8]4+ and [Cu5Mo3Fe4S11]6+ cores. Angew Chem Int Ed Engl 44:1971-4
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Huniar, Uwe; Ahlrichs, Reinhart; Coucouvanis, Dimitri (2004) Density functional theory calculations and exploration of a possible mechanism of N2 reduction by nitrogenase. J Am Chem Soc 126:2588-601
Koutmos, Markos; Coucouvanis, Dimitri (2004) Borohydride anions as terminal ligands on a Fe/Mo/S cluster. Synthesis, structure, and characterization of the [(Cl4-cat)(PPr3)MoFe3S4(BH4)2]2(Bu4N)4 double-fused cubane. Inorg Chem 43:6508-10
Koutmos, Markos; Coucouvanis, Dimitri (2004) Superclusters: a host-guest complex with a cyclic array of three bridged MoFe3S4 clusters. Angew Chem Int Ed Engl 43:5023-5
Coucouvanis, Dimitri; Han, Jaehong; Moon, Namdoo (2002) Synthesis and characterization of sulfur-voided cubanes. Structural analogues for the MoFe(3)S(3) subunit in the nitrogenase cofactor. J Am Chem Soc 124:216-24
Han, Jaehong; Coucouvanis, Dimitri (2002) Synthesis and structure of singly bridged and doubly bridged [MoFe(3)S(4)] double cubanes with bidentate phosphine ligands. Inorg Chem 41:2738-46
Han, J; Coucouvanis, D (2001) A new function of the (mu(3)-S) ligand in an Fe(4)S(4) cluster: synthesis and structure of the high-nuclearity Mo/Fe/S cluster, Fe(DMF)Cl(Cl(4)-cat)(2)-Mo(2)Fe(2)S(4)(PEt(3))(2)ClFe(4)S(4)(PEt(3))(3)(CO)(6)Cl. J Am Chem Soc 123:11304-5