Magnetization of the oxidized and reduced three-iron cluster of Desulfovibrio gigas ferredoxin II
- Citation:
- Magnetization of the oxidized and reduced three-iron cluster of Desulfovibrio gigas ferredoxin II, Day, E. P., Peterson J., Bonvoisin J. J., Moura I., and Moura J. J. , J Biol Chem, Mar 15, Volume 263, Number 8, p.3684-9, (1988)
Abstract:
The saturation magnetizations of the three iron cluster of ferredoxin II of Desulfovibrio gigas in both the oxidized and reduced states have been studied at fixed magnetic fields up to 4.5 tesla over the temperature range from 1.8 to 200 K. The low field (0.3 tesla) susceptibility of oxidized ferredoxin II obeys the Curie law over this entire temperature range. This establishes -2Jox greater than 200 cm-1 as the lower limit for the antiferromagnetic exchange coupling of oxidized ferredoxin II. The saturation magnetizations of reduced ferredoxin II at several fixed fields yield a nested family of curves which can be fit with spin S = 2 and D = -2.7(4) cm-1 (with E/D assigned the value 0.23 as determined by Mossbauer and EPR spectra). The low field susceptibility of reduced ferredoxin II also obeys the Curie law from approximately 4 up to 200 K. This establishes -2Jred greater than 40 cm-1 as the lower limit for the antiferromagnetic coupling of reduced ferredoxin II.
Notes:
0021-9258 (Print)0021-9258 (Linking)Journal ArticleResearch Support, U.S. Gov't, P.H.S.
