Iwasaki T, Isogai Y, Iizuka T, Oshima T
Department of Life Science, Tokyo Institute of Technology, Yokohama, Japan.
J Bacteriol. 1995 May;177(9):2576-82. doi: 10.1128/jb.177.9.2576-2582.1995.
A novel pink [2Fe-2S] protein has been purified from the cytosol fraction of the thermoacidophilic archaeon Sulfolobus sp. strain 7 (originally named Sulfolobus acidocaldarius 7) and called "sulredoxin." Its absorption, circular dichroism, and electron paramagnetic resonance spectra suggest the presence of a Rieske-type [2Fe-2S] cluster (g-factors of 2.01, 1.91, and 1.79; average g-factor [gav] = 1.90) which is remarkably similar to that of Thermus thermophilus respiratory Rieske FeS protein (J. A. Fee, K. L. Findling, T. Yoshida, R. Hille, G. E. Tarr, D. O. Hearshen, W. R. Dunham, E. P. Day, T. A. Kent, and E. Münck, J. Biol. Chem. 259:124-133, 1984) and distinctively different from those of the plant-type ferredoxins (gav = 1.96). Sulredoxin, which is the first Rieske-type [2Fe-2S] protein isolated from an archaeal species, does not function as an electron acceptor of the cognate 2-oxoacid:ferredoxin oxidoreductase. Whether sulredoxin is derived from the archaeal membrane-bound respiratory Rieske-type FeS center (gy = 1.91) is the subject of further investigation.
一种新型的粉红色[2Fe-2S]蛋白已从嗜热嗜酸古菌硫化叶菌属菌株7（原名为嗜酸硫化叶菌7）的胞质溶胶组分中纯化出来，并被命名为“硫铁氧还蛋白”。其吸收光谱、圆二色光谱和电子顺磁共振光谱表明存在一种Rieske型[2Fe-2S]簇（g因子分别为2.01、1.91和1.79；平均g因子[gav]=1.90），这与嗜热栖热菌呼吸Rieske FeS蛋白的簇显著相似（J.A.费伊、K.L.芬德林、T.吉田、R.希尔、G.E.塔尔、D.O.赫申、W.R.邓纳姆、E.P.戴、T.A.肯特和E.明克，《生物化学杂志》259:124-133，1984），与植物型铁氧还蛋白的簇明显不同（gav=1.96）。硫铁氧还蛋白是从古菌物种中分离出的首个Rieske型[2Fe-2S]蛋白，它不作为同源2-氧代酸：铁氧还蛋白氧化还原酶的电子受体。硫铁氧还蛋白是否源自古菌膜结合呼吸Rieske型FeS中心（gy=1.91）还有待进一步研究。
