Sulredoxin: a novel iron-sulfur protein of the thermoacidophilic archaeon Sulfolobus sp. strain 7 with a Rieske-type [2Fe-2S] center

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / analysis
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / isolation & purification
  • Circular Dichroism
  • Electron Spin Resonance Spectroscopy
  • Electron Transport Complex III*
  • Iron-Sulfur Proteins / chemistry*
  • Iron-Sulfur Proteins / isolation & purification
  • Mass Spectrometry
  • Molecular Sequence Data
  • Sequence Analysis
  • Spectrophotometry
  • Sulfolobus / chemistry*


  • Amino Acids
  • Bacterial Proteins
  • Iron-Sulfur Proteins
  • Rieske iron-sulfur protein
  • Electron Transport Complex III