Purification and characterization of a [3Fe-4S][4Fe-4S] type ferredoxin from hyperthermophilic archaeon, Pyrobaculum islandicum.

A ferredoxin was purified from the hyperthermophilic archaeon, Pyrobaculum islandicum. EPR spectra and metal content analyses suggested that the ferredoxin molecule contained one [3Fe-4S] and one [4Fe-4S] cluster. The ferredoxin was rapidly reduced by 2-oxoglutarate: ferredoxin oxidoreductase purified from P. islandicum, indicating that it functions physiologically as an electron sink for the redox enzymes participating in glycolytic metabolism. Furthermore, the amino acid sequence of the P. islandicum ferredoxin was compared with those of several other bacterial ferredoxins.