ESR studies on iron‐sulfur clusters of complex II in Ascaris suum mitochondria which exhibits strong fumarate reductase activity

FEBS Letters

Hata-Tanaka, Akiko²  Furushima, Rieko³  Itoh, Shigeru¹  Oya, Hiroshi³  Kita, Kiyoshi³ 

[1] National Institute for Basic Biology, Okazaki, Aichi 444, Japan;Department of Biology, Faculty of Science, University of Tokyo, Hongo, Tokyo 113 Japan;Department of Parasitology, Juntendo University of Medicine, Hongo, Tokyo 113 Japan

关键词: Iron-sulfur cluster;    Complex II;    Fumarate reductase;    ESR;    (Ascaris suum;    Nematoda);    E m;    oxidation-reduction midpoint potential;    P½;    apparent half-saturation parameter of ESR signal [1];   

DOI  :  10.1016/0014-5793(88)81012-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Complex II of Ascaris suum mitochondria, which functions as fumarate reductase in physiological conditions, contains three types of iron-sulfur clusters. These correspond to clusters S-1, S-2 and S-3 and are distinguishable by low-temperature ESR studies. Cluster S-1 is reduced by succinate, giving ESR signals with g _z, g _y and g _x values at 2.033, 1.939 and 1.920. The existence of cluster S-2 is suggested by an enhancement of the S-1 spin relaxation induced upon reduction of S-2 by dithionite. Cluster S-3 is ESR detectable under air-oxidized conditions and gives a strong signal at g= 2.025. Cluster S-3 was only partially reduced even with an excess amount of sodium succinate, which is a common characteristic of fumarate reductase but this is not seen in the mitochondrial complex II.

【 授权许可】

Unknown