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. 1984 Nov 15;224(1):247–251. doi: 10.1042/bj2240247

Azotobacter chroococcum 7Fe ferredoxin. Two pH-dependent forms of the reduced 3Fe clusters and its conversion to a 4Fe cluster.

S J George, A J Richards, A J Thomson, M G Yates
PMCID: PMC1144420  PMID: 6095817

Abstract

Ferredoxin from Azotobacter chroococcum has been studied by low-temperature magnetic-circular-dichroism and electron-paramagnetic-resonance spectroscopy. When aerobically isolated ferredoxin contains a [3Fe-4S] and [4Fe-4S] cluster. Anaerobic treatment with dithionite in the presence of ethanediol reduces the [3Fe-4S] cluster to give two spectroscopically distinct forms RI and RII which are reversibly interconvertible with a pKa approximately 7.5. The higher-pH form, RII, has a high affinity for ferrous ion and converts readily to a [4Fe-4S]1+ cluster, scavenging iron from the medium. The presence of the iron chelator EDTA inhibits this conversion.

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Selected References

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