Abstract

Free radicals occur in various physiological processes, and semiquinones are widespread and intimately involved in biological electron transfer processes. In order to extract more information about this, we investigated a number of semiquinone radicals with the 96Ghz (W-band) EPR spectrometer. At this high magnetic field, the increased Zeeman interaction can separate 'g' and 'a' tensors. The quinone systems examined so far include benzoquinone, catechol, methylcatechol, DOPA and DOPAMINE. Also, the effect of solvents on the 'g' tensor has been studied. It has been found that when going from protic to aprotic solvent there is an increase in 'g' values. Thus the formation of hydrogen bonds is of particular importance for better understanding of the role of free radicals of quinones in in vivo systems. We have examined a few proteins and are planning to carry out these studies on some more proteins which generate semiquinone radicals.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
2P41RR001811-11
Application #
5223625
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
11
Fiscal Year
1996
Total Cost
Indirect Cost

  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