Sulfolobus sp. strain

RR spectra of the Rieske protein from T. thermophilus (TRP) and of phthalate dioxygenase from Burkholderia cepacia (PDO) have been reported by Kuila et al. (66, 67), and those of the Rieske protein from Sulfolobus sp. strain 7 tentatively called sulredoxin by Iwasaki et al. (68). Although no complete analysis is yet available, several conclusions can be drawn from these spectra, in comparison to the spectra of proteins containing a 4-cysteine coordinated [2Fe-2S] cluster (Table VI). 

Ferredoxins from thermoacidophilic archaea such as Thermoplasma acidophi-lum and Sulfolobus sp. contain, in addition to one 3Fe-4S (cluster I) and one 4Fe-4S (cluster II) cluster, one zinc centre tetrahedrally co-ordinated to three histidines in the N-terminal region and to one aspartate in the ferredoxin core domain. These Fds contain an unusually long N-terminal extension region of unknown function, which was not detected in other bacterial type Fds. Upon oxidative degradation of Fd from Sulfolobus sp. strain 7 (Fopt = 80 cluster II is selectively converted into a cubane 3Fe-4S,... 

Fig. 21. Comparison of the projection structures of the surface protein from various archaea. From ref [139]. (A) Hyperthermus butylicus (lattice constant 25.8 nm) (B) Pyrodictium occuUum (lattice constant 21.8nm) (C) Archaeoglobus fulgidus (lattice constant 17.5nm) (D) Sulfolobus sp. (strain B6/2) (lattice constant 21.0nm) (E) Thermococcus celer (lattice constant IS.Onm) (F) Desulfumcoccus mobilis (lattice constant 18.0 nm).

Trent, J. D., Osipiuk.J., andPinkau, T. (1990). Acquired thermotolerance and heat shock in the extremely thermophilic archaebacterium Sulfolobus sp. strain B12./. Bacteriol. 172,1478-1484. 

Organism and Cell Culture. Sulfolobus sp. strain 7 (originally named S. acido-caldarius strain 7 isolated from Beppu hot springs, Kyushu, Japan ) is a strictly aerobic and thermoacidophilic crenarchaeote that grows optimally at 75-80° and at pH 2.5-3.0. The 16S rRNA sequence and biochemical analysis of the isolate suggested that it is a novel crenarchaeote, belonging to the genus Sulfolobus. ... 

Sulfolobus sp. strain 7 (JCM 10545) is cultivated aerobically and chemo-heterotrophically in the shaking culture at pH 2.5-3 and 75-80°, and harvested in the late exponential phase of the growth as previously described. ... 

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. 

Zanc-containing ferredoxin is the most abundant ferredoxin in chemohetero-trophically grown Sulfolobus sp. strain and T. acidophilum. The types and spectroscopic properties of the iron-sulfur clusters and the isolated zinc center are very similar in archaeal zinc-containing ferredoxins (Table I). Zinc-containing ferredoxin from Sulfolobus sp. strain 7 (103 amino acids, 7 cysteines) contains one [3Fe-4S] cluster (cluster I) with a midpoint redox potential of —280 mV, one [4Fe-4S] cluster (cluster II) with a midpoint redox potential of —530 mV, and a tetragonal zinc center. j acidophilum zinc-containing ferredoxin... 

Fig. 2. The 2.0-A resolution crystal structure of the 6Fe-containing form of zinc-containing ferre-doxin from Sulfolobus sp. strain (PDB entry, IXER [T. Fujii, Y. Hata, T. Wakagi, N. Tanaka, and T. Oshima, Nat. Struct. Biol. 3, 834 (1996) T. Fujii, Y. Hata, M. Oozeki, H. Moriyama, T. Wakagi, N. Tanaka, and T. Oshima, Biochemistry 36, 1505 (1997)]). Important residues are labeled. The model was drawn using the Insight II software (Molecular Simulations Inc.).

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. ... 

Fukuda E, Kino H, Matsuzawa H, Wakagi T (2001) Role of a highly conserved YPITP motif in 2-oxoacid ferredoxin oxidoreductase heterologous expression of the gene from Sulfolobus sp strain 7, characterization of the recombinant and variant enzymes. Eur J Biochem 268 5639-5646... 

Zhang, Q., Iwasaki, T., Wakagi, T., and Oshima, T., 1996. 2-Oxoacid ferre-doxin oxidoreductase from the thermoacidophilie arehaeon, Sulfolobus sp. strain 7. The Journal of Biochemistry. 120 587-599. 

Zhang Q, Iwasaki T, Wakagi T, Oshima T. 1996. 2-oxoacid ferredoxin oxidoreductase from the thermoacidophilic archaeon Sulfolobus sp strain 7. J Biochem 120 587-599. 

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