Abstract

X-band EPR studies on methylmalonyl-CoA mutase in Prof. Banerjee's laboratory show rather messy-looking spectra that seems to represent contributions from two separate species (JBC, 1995, 270:9295; JACS, 1995, 117:7033). This system requires additional information for a definitive interpretation. The Banerjee group has between 60 and 80 uM spin associated with the catalytic intermediate, which has a crossover g value at 2.11. By selective isotope substitution studies, the signals are deduced to show a biradical intermediate which has an exchange coupled Co(II)-organic radical pair. This is a steady-state sample, and they have never been able to get more than 0.4 spin/mol of enzyme. High-field EPR is being undertaken with the hope that we can separate the signals and eventually simulate the spectra. Sample handling is challenging, as the enzyme must be handled anaerobically prior to freezing, and the capillary sample tubes are difficult to load, ship, preserve in frozen state, and load ed into the spectrometer without thawing or contamination. Nevertheless, progress is being made, and preliminary Q-band and W-band spectra have been obtained at the IERC. This project will continue in 1998.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR001811-13
Application #
6120694
Study Section
Project Start
1998-04-15
Project End
1999-11-30
Budget Start
1997-10-01
Budget End
1998-09-30
Support Year
13
Fiscal Year
1998
Total Cost
Indirect Cost

  Institution

Name
University of Illinois at Chicago
Department
Type
DUNS #
121911077
City
Chicago
State
IL
Country
United States
Zip Code
60612

  Publications

Hurth, Kyle M; Nilges, Mark J; Carlson, Kathryn E et al. (2004) Ligand-induced changes in estrogen receptor conformation as measured by site-directed spin labeling. Biochemistry 43:1891-907
Woodmansee, Anh N; Imlay, James A (2002) Reduced flavins promote oxidative DNA damage in non-respiring Escherichia coli by delivering electrons to intracellular free iron. J Biol Chem 277:34055-66
Denisov, Ilia G; Makris, Thomas M; Sligar, Stephen G (2002) Formation and decay of hydroperoxo-ferric heme complex in horseradish peroxidase studied by cryoradiolysis. J Biol Chem 277:42706-10
Atsarkin, V A; Demidov, V V; Vasneva, G A et al. (2001) Mechanism of oxygen response in carbon-based sensors. J Magn Reson 149:85-9
Mangels, M L; Harper, A C; Smirnov, A I et al. (2001) Investigating magnetically aligned phospholipid bilayers with EPR spectroscopy at 94 GHz. J Magn Reson 151:253-9
Breitzer, J G; Smirnov, A I; Szczepura, L F et al. (2001) Redox properties of C6S8(n-) and C3S5(n-) (n = 0, 1, 2): stable radicals and unusual structural properties for C-S-S-C bonds. Inorg Chem 40:1421-9
Denisov, I G; Hung, S C; Weiss, K E et al. (2001) Characterization of the oxygenated intermediate of the thermophilic cytochrome P450 CYP119. J Inorg Biochem 87:215-26
Kirkor, E S; Scheeline, A (2000) Nicotinamide adenine dinucleotide species in the horseradish peroxidase-oxidase oscillator. Eur J Biochem 267:5014-22
Rapoport, N; Smirnov, A I; Pitt, W G et al. (1999) Bioreduction of Tempone and spin-labeled gentamicin by gram-negative bacteria: kinetics and effect of ultrasound. Arch Biochem Biophys 362:233-41
Maringanti, S; Imlay, J A (1999) An intracellular iron chelator pleiotropically suppresses enzymatic and growth defects of superoxide dismutase-deficient Escherichia coli. J Bacteriol 181:3792-802

Showing the most recent 10 out of 16 publications