Magnetic circular dichroism study of the selenium-substituted form (Fe3Se4) of bovine heart aconitase.
The selenium-substituted inactive form of mitochondrial aconitase contains one [3Fe-4Se]1+/0 cluster [Surerus, Kennedy, Beinert and Münck (1989) Proc. Natl. Acad. Sci. U.S.A. 87, 9846-9850]. This cluster was studied in both oxidized and reduced states by magnetic CD (MCD) and EPR spectroscopy. In the MCD spectra, intensity and transition wavelength shifts are observed when compared with the spectra of the native [3Fe-4S]1+/0 cluster. These changes are used to differentiate between the charge-transfer transitions originating from inorganic and cysteinyl sulphur. Using also the data from the EPR spectra, the spin ground state is assigned as S = 1/2 for the oxidized [3Fe-4Se]1+ cluster and S = 2 for the reduced [3Fe-4Se]0 cluster.
Breton
J L
JL
Centre for Metalloprotein Spectroscopy and Biology, School of Chemical Sciences, University of East Anglia, Norwich, UK.
Farrar
J A
JA
Kennedy
M C
MC
Beinert
H
H
Thomson
A J
AJ
D000154:Aconitate Hydratase / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D004578:Electron Spin Resonance Spectroscopy; D007501:Iron / Q000737:chemistry*; D008280:Magnetics; D009206:Myocardium / Q000201:enzymology*; D010084:Oxidation-Reduction; D012643:Selenium / Q000737:chemistry*
D007501:Iron; D000154:Aconitate Hydratase; D012643:Selenium