The overall goal of this project is to understand the structure and function of diiron-oxo sites in proteins. Two such proteins have been chosen as the focus of investigations: hemerythrin (and myohemerythrin), an O 2-carrying protein from marine invertebrates, rubreythrin, a protein of unknown biological function form anaerobic sulfate-reducing bacteria, and bacterioferritin,and iron storage protein found in several bacteria. Since the structure and function of hemerythrin is already known in some detail, the proposed research aims to examine a relatively neglected but crucial aspect, namely, the roles of conserved residues lining the O2 binding pocket in modulation of O2 affinity and in protection of the diiron site against autoxidation. Rubrerythrin is a diiron-oxo from the anaerobic sulfate-reducing bacterium, Desulfovibrio vulgaris. The major unsolved problem for this protein is biological function. The results obtained during the previous projects period show that the diiron domain of the rubreythrin subunit a strong structural resemblance to the subunits of the iron storage proteins, ferritin and bacterioferritin. The results strongly suggest that rubreythrin's biological function involves iron metabolism, perhaps connected to oxygen tolerance of the bacteria. A systematic investigation of the function of rubrerythrin both in vitro and in vivo is proposed. Since many infections bacteria have developed mechanisms for obtaining iron from their host, an understanding of iron metabolism in the bacteria mentioned above will increase our understanding of pathogenesis. This includes anaerobic sulfate-reducing bacteria, which have been found in the human gut. A health-related goal of understanding the dioxygen- carrying mechanism of hemerythrin is to develop this protein for use in blood substitutes.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM040388-08
Application #
2022235
Study Section
Metallobiochemistry Study Section (BMT)
Project Start
1988-07-01
Project End
2001-03-31
Budget Start
1997-04-01
Budget End
1998-03-31
Support Year
8
Fiscal Year
1997
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
Weitz, Andrew C; Giri, Nitai; Caranto, Jonathan D et al. (2017) Spectroscopy and DFT Calculations of a Flavo-diiron Enzyme Implicate New Diiron Site Structures. J Am Chem Soc 139:12009-12019
Miner, Kyle D; Kurtz Jr, Donald M (2016) Active Site Metal Occupancy and Cyclic Di-GMP Phosphodiesterase Activity of Thermotoga maritima HD-GYP. Biochemistry 55:970-9
Frederick, Rosanne E; Caranto, Jonathan D; Masitas, Cesar A et al. (2015) Dioxygen and nitric oxide scavenging by Treponema denticola flavodiiron protein: a mechanistic paradigm for catalysis. J Biol Inorg Chem 20:603-13
Caranto, Jonathan D; Weitz, Andrew; Giri, Nitai et al. (2014) A diferrous-dinitrosyl intermediate in the N2O-generating pathway of a deflavinated flavo-diiron protein. Biochemistry 53:5631-7
Caranto, Jonathan D; Weitz, Andrew; Hendrich, Michael P et al. (2014) The nitric oxide reductase mechanism of a flavo-diiron protein: identification of active-site intermediates and products. J Am Chem Soc 136:7981-92
Okamoto, Yasunori; Onoda, Akira; Sugimoto, Hiroshi et al. (2014) H2O2-dependent substrate oxidation by an engineered diiron site in a bacterial hemerythrin. Chem Commun (Camb) 50:3421-3
Miner, Kyle D; Klose, Karl E; Kurtz Jr, Donald M (2013) An HD-GYP cyclic di-guanosine monophosphate phosphodiesterase with a non-heme diiron-carboxylate active site. Biochemistry 52:5329-31
Okamoto, Yasunori; Onoda, Akira; Sugimoto, Hiroshi et al. (2013) Crystal structure, exogenous ligand binding, and redox properties of an engineered diiron active site in a bacterial hemerythrin. Inorg Chem 52:13014-20
Caranto, Jonathan D; Gebhardt, Linda L; MacGowan, Charles E et al. (2012) Treponema denticola superoxide reductase: in vivo role, in vitro reactivities, and a novel [Fe(Cys)(4)] site. Biochemistry 51:5601-10
Hayashi, Takahiro; Caranto, Jonathan D; Matsumura, Hirotoshi et al. (2012) Vibrational analysis of mononitrosyl complexes in hemerythrin and flavodiiron proteins: relevance to detoxifying NO reductase. J Am Chem Soc 134:6878-84

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