X-ray absorption spectroscopic (XAS) investigations designed to elucidate the electronic and molecular structures of the active sites of a variety of metalloenzymes will be carried out. In each case, structure-function relationships will be developed by determining structural changes accompanying redox and/or substrate- binding steps of the enzyme's catalytic cycle. The ultimate goal is to understand the molecular mechanisms of catalysis by these enzymes. Studies on cytochrome c oxidases from beef heart (cytochrome aa3) and Thermus thermophilous (cytochrome ba3) are designed to elucidate the Cu-Fe binuclear O2-interaction site structure in the resting state and at various stages of turnover (by examining stable analogs of O2 intermediates). Examples of all known types of nickel-containing enzymes, including jackbean urease, Klebsiella aerogenes urease, Desulfovibrio gigas (NiFe) hydrogenase, D. baculatus (NiFeSe) hydrogenase, Clostridium thermoaceticum CO dehydrogenase, and Methanobacterium thermoautotrophicum S-methyl coenzyme-M reductase, will be compared in terms of their nickel site structures. Emphasis will be placed on isolated F430, the nickel-containing tetrapyrrole prosthetic group of methyl reductase, for which ligand-binding studies will help identify any protein-derived axial ligands in methyl reductase. Other physicochemical studies of F430 and methyl reductase will be directed at elucidating the mechanism of CH4 production in this final enzymatic step of methanogenesis. Comparative studies are also planned on amine oxidases from a number of sources to elucidate the local structural environment of the copper sites and their involvement with the organic cofactor in oxidation of primary amines.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM042025-02
Application #
3300564
Study Section
Physical Biochemistry Study Section (PB)
Project Start
1989-04-01
Project End
1994-03-31
Budget Start
1990-04-01
Budget End
1991-03-31
Support Year
2
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Georgia
Department
Type
Schools of Arts and Sciences
DUNS #
City
Athens
State
GA
Country
United States
Zip Code
30602
Tao, Ye; Shokes, Jacob E; McGregor, Wade C et al. (2012) Structural characterization of Zn(II)-, Co(II)-, and Mn(II)-loaded forms of the argE-encoded N-acetyl-L-ornithine deacetylase from Escherichia coli. J Inorg Biochem 111:157-63
Gale, Eric M; Cowart, Darin M; Scott, Robert A et al. (2011) Dipeptide-based models of nickel superoxide dismutase: solvent effects highlight a critical role to Ni-S bonding and active site stabilization. Inorg Chem 50:10460-71
Grossoehme, Nicholas; Kehl-Fie, Thomas E; Ma, Zhen et al. (2011) Control of copper resistance and inorganic sulfur metabolism by paralogous regulators in Staphylococcus aureus. J Biol Chem 286:13522-31
Reyes-Caballero, Hermes; Guerra, Alfredo J; Jacobsen, Faith E et al. (2010) The metalloregulatory zinc site in Streptococcus pneumoniae AdcR, a zinc-activated MarR family repressor. J Mol Biol 403:197-216
Yang, Hua; Lipscomb, Gina L; Keese, Annette M et al. (2010) SurR regulates hydrogen production in Pyrococcus furiosus by a sulfur-dependent redox switch. Mol Microbiol 77:1111-22
Schofield, Robert M S; Niedbala, Jack C; Nesson, Michael H et al. (2009) Br-rich tips of calcified crab claws are less hard but more fracture resistant: a comparison of mineralized and heavy-element biological materials. J Struct Biol 166:272-87
Ma, Zhen; Cowart, Darin M; Scott, Robert A et al. (2009) Molecular insights into the metal selectivity of the copper(I)-sensing repressor CsoR from Bacillus subtilis. Biochemistry 48:3325-34
Ma, Zhen; Cowart, Darin M; Ward, Brian P et al. (2009) Unnatural amino acid substitution as a probe of the allosteric coupling pathway in a mycobacterial Cu(I) sensor. J Am Chem Soc 131:18044-5
Jackson-Rosario, Sarah; Cowart, Darin; Myers, Andrew et al. (2009) Auranofin disrupts selenium metabolism in Clostridium difficile by forming a stable Au-Se adduct. J Biol Inorg Chem 14:507-19
Lipscomb, Gina L; Keese, Annette M; Cowart, Darin M et al. (2009) SurR: a transcriptional activator and repressor controlling hydrogen and elemental sulphur metabolism in Pyrococcus furiosus. Mol Microbiol 71:332-49

Showing the most recent 10 out of 53 publications