Resolution of the aerobic respiratory system of the thermoacidophilic archaeon, Sulfolobus sp. strain 7. III. The archaeal novel respiratory complex II (succinate:caldariellaquinone oxidoreductase complex) inherently lacks heme group

J Biol Chem. 1995 Dec 29;270(52):30902-8. doi: 10.1074/jbc.270.52.30902.


An active respiratory complex II (succinate:quinone oxidoreductase) has been purified from tetraether lipid membranes of the thermoacidophilic archaeon, Sulfolobus sp. strain 7. It consists of four different subunits with apparent molecular masses of 66, 37, 33, and 12 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The 66-kDa subunit contains a covalently bound flavin, the 37-kDa subunit is a possible iron-sulfur protein carrying three distinct types of EPR-visible FeS cluster, and the 33- and 12-kDa subunits are putative membrane-anchor subunits, respectively. While no heme group is detected in the purified complex II, it catalyzes succinate-dependent reduction of ubiquinone-1 and 2,6-dichlorophenolindophenol in the absence of phenazine methosulfate. The respiratory complex II of Sulfolobus sp. strain 7 appears to be novel in that it functions as a true succinate:caldariellaquinone oxidoreductase, although inherently lacking any heme group. This further indicates that the heme group of several respiratory complexes II may not be involved in the redox intermediates of the electron transfer from succinate to quinone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Electron Spin Resonance Spectroscopy
  • Electron Transport Complex II
  • Heme / metabolism*
  • Kinetics
  • Molecular Sequence Data
  • Multienzyme Complexes / chemistry
  • Multienzyme Complexes / isolation & purification
  • Multienzyme Complexes / metabolism*
  • Oxidoreductases / chemistry
  • Oxidoreductases / isolation & purification
  • Oxidoreductases / metabolism*
  • Oxygen / metabolism*
  • Sequence Homology, Amino Acid
  • Spectrophotometry, Ultraviolet
  • Succinate Dehydrogenase / chemistry
  • Succinate Dehydrogenase / isolation & purification
  • Succinate Dehydrogenase / metabolism*
  • Sulfolobus / enzymology
  • Sulfolobus / metabolism*


  • Multienzyme Complexes
  • Heme
  • Oxidoreductases
  • Electron Transport Complex II
  • Succinate Dehydrogenase
  • Oxygen