Coenzyme M binds to a [4Fe–4S] cluster in the active site of heterodisulfide reductase as deduced from EPR studies with the [33S]coenzyme M‐treated enzyme

FEBS Letters

Jaun, Bernhard¹  Bauer, Carsten¹  Duin, Evert C.²  Hedderich, Reiner² 

[1]Laboratorium für Organische Chemie, Eidgenössische Technische Hochschule Zürich, ETH Hönggerberg HCI, 8093 Zürich, Switzerland

[2]Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany

关键词: Heterodisulfide reductase;    Iron–sulfur protein;    Electron paramagnetic resonance spectroscopy;    Methanothermobacter marburgensis;    Methanosarcina barkeri;    Hdr;    heterodisulfide reductase;    CoM-SH;    coenzyme M or 2-mercaptoethane sulfonate;    CoB-SH;    coenzyme B or 7-mercaptoheptanoylthreonine phosphate;    CoM-S–S-CoB;    heterodisulfide of CoM-SH and CoB-SH;    CoM-SeH;    2-selanyl-ethane sulfonate;    CoM-Hdr;    oxidized Hdr incubated with CoM-SH;    CoB-Hdr;    oxidized Hdr incubated with CoB-SH;    FTR;    ferredoxin:thioredoxin reductase;    NEM-FTR;    N-ethylmaleimide-modified FTR;   

DOI  :  10.1016/S0014-5793(03)00134-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Heterodisulfide reductase (Hdr) from methanogenic Archaea catalyzes the reversible reduction of the heterodisulfide (CoM-S–S-CoB) of the methanogenic thiol coenzymes, coenzyme M (CoM-SH) and coenzyme B (CoB-SH). Upon reaction of the oxidized enzyme with CoM-SH a unique paramagnetic species is formed, which has been shown to be due to a novel type of [4Fe–4S]³⁺ cluster. In this work, it was addressed whether CoM-SH is directly attached to this [4Fe–4S] cluster using CoM-³³SH as substrate and purified Hdr from Methanothermobacter marburgensis and Methanosarcina barkeri. With both enzymes treatment with CoM-³³SH in the presence of duroquinone as an oxidant resulted in a significant broadening of the electron paramagnetic resonance spectrum as compared to CoM-SH as substrate. The signal broadening resulted from an unresolved anisotropic hyperfine coupling between the ³³S nucleus and the paramagnetic center. The results provide compelling evidence for a direct binding of CoM-SH to the [4Fe–4S] cluster in the active site of the enzyme.

【 授权许可】

Unknown