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PMID: 6095817 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

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

The Biochemical journal ·Vol. 224 ·No. 1 ·1984-11-15 ·Pages 247-51

George SJ, Richards AJ, Thomson AJ, Yates MG

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.

MeSH Terms
Azotobacter/analysis Chemical Phenomena Chemistry Circular Dichroism Dithionite Edetic Acid Electron Spin Resonance Spectroscopy Ferredoxins Hydrogen-Ion Concentration Iron/analysis Temperature
Chemicals
Ferredoxins Dithionite Edetic Acid Iron
Authors & Affiliations
4 authors, click to expand affiliations / ORCID
George S J
Richards A J
Thomson A J
Yates M G
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19 references, click to expand
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Article Info
Journal
The Biochemical journal
Abbr.
Biochem J
ISSN
0264-6021
DOI
10.1042/bj2240247
Published
1984-11-15
Pages
247-51
Language
English
Region
England
NLM ID
2984726R
PMCID
PMC1144420
Subset
IM
External Links
PubMed source DOI: 10.1042/bj2240247 PMC Full Text View journal details
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