Ferredoxin, Sulfolobus purification

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Purification of Zinc-Containing Ferredoxin from Sulfolobus sp. Strain 7. The isolation of ferredoxin from the aerobic thermoacidophilic crenarchaeote, Sulfolobus acidocaldarius, was described by Kerscher et al. This procedure was adapted to purify ferredoxin and related metalloproteins from the Sulfolobus sp. strain 7 cells. 

Several iron-sulfur proteins can be purified from the same batch of the Sulfolobus sp. strain 7 cells together with the cognate zinc-containing ferredoxin. Purification and some properties of these proteins are described below. 

Purification. Purification of the 2-oxoacid ferredoxin oxidoreductase of Sulfolobus sp. strain 7 is carried out by following the 2-oxoacid ferredoxin oxidoreductase activity (as described below) and the absorption bands at 280, 408, and 450 nm of each fraction at different steps. 

In anaerobic archaea, ferredoxin functions as an intermediate electron acceptor of a variety of key steps in the central metabolic pathways involved in saccharolytic and peptide fermentation, and reduced ferredoxin thus formed donates its reducing equivalent to ferredoxiniNADP" oxidoreductase and hydrogenase. - In aerobic and thermoacidophilic archaea, the reoxidation steps of reduced zinc-containing ferredoxin are poorly characterized. The soluble fraction of Sulfolobus sp. strain 7 also contains an NADPH ferredoxin oxidoreductase activity, but this enzyme has not been purified and characterized. The following section describes the purification and partial characterization of a red iron-sulfur flavoprotein with a weak ferredoxin-reoxidizing activity fi om Sulfolobus sp. strain 7. ... 

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