title: A stable intermediate product of the archaeal zinc-containing 7Fe ferredoxin from Sulfolobus sp. strain 7 by artificial oxidative conversion.
abstract: Irreversible conversion of the purified zinc-containing 7Fe ferredoxin from the thermoacidophilic archaeon Sulfolobus sp. strain 7 was found to occur under aerobic conditions at pH 5.0 and at 4 degrees C. This process accompanied a substantial increase of the electron paramagnetic resonance signal attributed to a [3Fe-4S]1+ cluster, and the converted form containing approximately 6 Fe/Zn (mol/mol) had a net charge different from that of the native 7Fe ferredoxin. These data provide evidence for the formation of a stable intermediate product of the archaeal ferredoxin having two [3Fe-4S] clusters and a zinc center by artificial oxidative degradation. This further explains the discrepancy that a zinc center and two [3Fe-4S] clusters (but not a zinc center and one [3Fe-4S] cluster plus one [4Fe-4S] cluster) are observed in the crystal structure at pH 5.0.
authors.affiliation: Department of Biochemistry and Molecular Biology, Nippon Medical School, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Iwasaki
authors.forename: T
authors.initials: T
authors.lastname: Oshima
mesh_terms: D000332:Aerobiosis; D004578:Electron Spin Resonance Spectroscopy; D004591:Electrophoresis, Polyacrylamide Gel; D005288:Ferredoxins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D007506:Iron-Sulfur Proteins / Q000737:chemistry; D008970:Molecular Weight; D010084:Oxidation-Reduction; D016944:Sulfolobus / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry
chemical_list: D005288:Ferredoxins; D007506:Iron-Sulfur Proteins; D007501:Iron; D015032:Zinc