Evidence for a unique Rieske iron‐sulphur centre in Heliobacterium chlorum

FEBS Letters

Nitschke, Wolfgang¹  Liebl, Ursula¹  Rutherford, A.William¹ 

[1]Service de Biophysique, Département de Biologie, CEN Saclay, 91 191 Gif-sur-Yvette Cedex, France

关键词: Rieske center;    Heliobacterium chlorum;    Cytochrome bc-complex;    Inhibitor;    Qo-site;    Electron paramagnetic resonance spectrometry;    DBMIB;    2;    5-dibromo-3-methyl-6-isopropyl-benzo-quinone;    EDTA;    ethylenediaminetetraacetate;    FeS centre;    iron-sulphur centre;    Mops;    4-morpholinepropanesulphonic acid;    Qo-site;    the quinone-oxidizing site of cytochrome bc complexes;    SDS-PAGE;    sodium dodecyl sulphate polyacrylamide gel electrophoresis;    UHDBT;    5-(n-undecyl)-6-hydroxy-4;    7-dioxobenzothiazole;   

DOI  :  10.1016/0014-5793(90)80608-L

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

An iron sulphur centre (g _z = 2.035, g _y =1.89, g _x =1.81), which can be observed in both whole cells and isolated plasma membranes of Heliobacterium chlorum, was identified as a Rieske centre on the basis of its sensitivity to the inhibitors 2,5-dibromo-3-methyl-6-isopropyl-benzoquinone (DBMIB), 5-(n-undecyl)-6-hydroxy-4,7-dioxobenzothiazole (UHDBT) and stigmatellin as well as on the basis of its orientation (gx, is oriented perpendicular and g _y is oriented parallel to the membrane plane). Its midpoint potential is unusually low (E _m,7= +120 ± 10 mV) and does not depend on pH in the range between pH 6.5 and pH 8.0. The effects of the inhibitors on the EPR spectrum are altered compared to Rieske centres in other systems. The significance of the low E _m is discussed with regard to the overall midpoint potentials of the electron transfer chain in Heliobacterium chlorum.

【 授权许可】

Unknown