ESEEM studies of succinate:ubiquinone reductase from Paracoccus denitrificans
Abstract
Electron spin-echo envelope modulation (ESEEM) spectroscopy has been performed in order to obtain structural information about the environment of the reduced [2Fe-2S] cluster (S-1 center), the oxidized [3Fe-4S] cluster (S-3 center), and the flavin semiquinone radical in purified succinate:ubiquinone reductase from Paracoccus denitrificans. Spectral simulations of the ESEEM data from the reduced [2Fe-2S] yielded nuclear quadrupole interaction parameters that are indicative of peptide nitrogens. We also observed a weak interaction between the oxidized [3Fe-4S] cluster and a peptide ¹⁴N. There was no evidence for coordination of any of the Fe atoms to ¹⁴N atoms of imidazole rings. The ESEEM data from the flavin semiquinone radical were more complicated. Here, evidence was obtained for interactions between the unpaired electron and only the two nitrogen atoms in the flavin ring.
Additional Information
© 2000 SBIC. Received 29 July 1999; Accepted 16 May 2000; Published online: 27 July 2000. We would like to thank Dr. Chrisopher J. Bender and Biotechnology Resource in Pulsed EPR Spectroscopy at Albert Einstein College of Medicine for providing us with a copy of their spectral simulation program. This work was supported by the NIH grants GM22432 to (S.I.C.) and GM48242 (to R.D.B.) from the U.S. Public Health Service.Additional details
- Eprint ID
- 101384
- DOI
- 10.1007/s007750000142
- Resolver ID
- CaltechAUTHORS:20200219-114918387
- GM22432
- NIH
- GM48242
- NIH
- Created
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2020-02-19Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field