title: Electron spin-echo spectroscopic studies of Escherichia coli fumarate reductase.
abstract: Electron spin-echo envelope modulation (ESEEM) spectroscopy was applied to the study of reduced Centre 1 of Escherichia coli fumarate reductase (succinate:(acceptor) oxidoreductase, EC 1.3.99.1). The ESEEM spectrum derived from stimulated (3-pulse) echo envelopes obtained at 8.8 GHz contained lines at 0.9, 2.1, 3.0 and 4.2 MHz in the g = 1.94 region. When studied at 11.4 GHz, these low-frequency components scale with magnetic field in a manner indicating interaction between the unpaired electron spin of the Fe-S cluster and a weakly coupled 14N nucleus. Spectral simulations of these ESEEM data yield nuclear quadrupole interaction parameters indicative of peptide nitrogen. For oxidized protein, the magnetic-field dependence of the linear electric-field effect (LEFE) for Centre 3 was measured, and the results confirm the presence of a [3Fe-4S] cluster in the protein.
authors.affiliation: Department of Biochemistry, Kings College, London, U.K.
authors.forename: R
authors.initials: R
authors.lastname: Cammack
authors.forename: A
authors.initials: A
authors.lastname: Chapman
authors.forename: J
authors.initials: J
authors.lastname: McCracken
authors.forename: J B
authors.initials: JB
authors.lastname: Cornelius
authors.forename: J
authors.initials: J
authors.lastname: Peisach
authors.forename: J H
authors.initials: JH
authors.lastname: Weiner
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000201:enzymology*; D005583:Fourier Analysis; D007700:Kinetics; D010084:Oxidation-Reduction; D013385:Succinate Dehydrogenase / Q000378:metabolism*
chemical_list: D013385:Succinate Dehydrogenase