Evidence for a novel type of iron cluster in the respiratory chain of the archaeon Sulfolobus metallicus

FEBS Letters

Teixeira, Miguel²  Gomes, Cláudio M²  Huber, Harald¹  Stetter, Karl O¹ 

[1] Lehrstuhl für Mikrobiologie der Universität Regensburg, 93053 Regensburg, Germany;Instituto de Tecnologia Quı́mica e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande 6, Apt 127, 2780 Oeiras, Portugal

关键词: Archaeon;    Electron paramagnetic resonance;    Iron-sulphur;    Rieske;    Terminal oxidase;    Thermophile;   

DOI  :  10.1016/S0014-5793(98)00836-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A new type of metal centre was detected in the membranes of the thermoacidophilic archaeon Sulfolobus metallicus. This centre has an S=1/2 ground state in the oxidised form, yielding an axial EPR signal with g values at 2.035 (g _||) and 1.97 (g _⊥), optimally detected at 4.6–10 K; in the reduced form it is EPR silent (even spin). These magnetic properties point to a spin-coupled iron cluster, with a minimum of two iron ions. The centre has a high reduction potential of +350 mV, at pH 6.5. The physiological role of this novel centre was probed through a general characterisation of S. metallicus respiratory chain: this archaeon contains NADH and succinate dehydrogenase activities, and cytochromes b ₅₆₂, a ₅₈₆ and a ₆₀₀ on the oxygen reductase system. Since it is reduced in the presence of succinate, and taking into account its high reduction potential, this centre is proposed to be a functional analogue of the Rieske centres.

【 授权许可】

Unknown