title: Characterization and determination of the redox properties of the 2[4Fe-4S] ferredoxin from Methanosarcina barkeri strain MS.
abstract: Ferredoxin was purified from methanol-grown Methanosarcina barkeri strain MS. It was isolated as a dimer with a subunit molecular weight of 6,200. The protein contained 7.4 mol iron and 7.2 mol acid-labile sulfur per monomer. In the reduced state the ferredoxin exhibited an EPR spectrum characteristic of two spin-coupled [4Fe-4S]1+ clusters. The EM of the [4Fe-4S]2+:1+ couple was -322 mV +/- 3 mV vs. NHE at 21 degrees C and pH 7.0. The midpoint potential was temperature but not pH dependent. At the physiological temperature of 37 degrees C the Em was -340 mV.
authors: Department of Microbiology, Faculty of Science, University of Nijmegen, The Netherlands.
authors: P J
authors: PJ
authors: Daas
authors: W R
authors: WR
authors: Hagen
authors: J T
authors: JT
authors: Keltjens
authors: G D
authors: GD
authors: Vogels
mesh_terms: D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D005288:Ferredoxins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D017021:Methanosarcina barkeri / Q000378:metabolism*; D008970:Molecular Weight; D010084:Oxidation-Reduction; D013816:Thermodynamics
chemical_list: D005288:Ferredoxins; D046911:Macromolecular Substances