Abstract
A high-potential iron-sulfur cluster with characteristics similar to a Rieske-type center was detected in the plasma membrane of Sulfolobus acidocaldarius by EPR spectroscopy. In the reduced form this center has g-values of gz = 2.031, gy = 1.890 and gx = 1.725 (gav = 1.88, rhombicity = 0.37) and its reduction potential at pH 7.4 was determined to be +325 ± 10 mV. The archaebacterial cluster exhibits some unique properties, in comparison to eubacterial and eukaryotic Rieske-type centers. First, the reduction potential is pH-dependent in the range from pH 6.7 to 8.2. Second, the typical inhibitor of Rieske FeS centers, DBMIB, had no effect on the g-values of this cluster. The center is reducible by both NADH and succinate in the presence of cyanide, an inhibitor of the terminal oxidases. The possible role of a Rieske-type center in an organism lacking any c-type cytochromes is discussed.
| Original language | English |
|---|---|
| Journal | FEBS Letters |
| Volume | 318 |
| Issue number | 1 |
| Pages (from-to) | 61-64 |
| Number of pages | 4 |
| ISSN | 0014-5793 |
| DOIs | |
| Publication status | Published - 22.02.1993 |
Funding
Acknowledgements: This work was supportedb y JNICT, Portugal (GrantS TRDA/C/BI0/416/92t o M.T.) andg rantsf rom theD eutsche Forschungsgemeinscha(tfot S.A. and G.S.). We thank Prof. A.V. Xavierf or criticald iscussionas ndD r. E. Bill (Ltibeck)f or runnmgt he EPR spectras hownin Fig. 5.
Research Areas and Centers
- Academic Focus: Center for Infection and Inflammation Research (ZIEL)
