Membrane‐bound F420H2‐dependent heterodisulfide reductase in methanogenic bacterium strain Göl and Methanolobus tindarius

FEBS Letters

Mahlmann, A.¹  Blaut, M.¹  Deppenmeier, U.¹  Gottschalk, G.¹ 

[1] Institut für Mikrobiologie der Georg-August-Universität, Göttingen, FRG

关键词: F420;    Heterodisulfide reductase;    Methane formation;    Membrane;    Methanogenic bacteria;    CoM-SH;    2-mercaptoethanesulfonate;    DTNB;    5;    5'-dithio-bis(2-nitrobenzoic acid);    F420;    (N-L-lactyl-γ-L-glutamyl)-L-glutamic acid phosphodiester of 7;    8-didemethyl-8-hydroxy-5-deazariboflavin-5 '-phosphate;    F420H2;    reduced F420;    MF;    methano-furan;    H4MPT;    tetrahydromethanopterin;    HTP-SH;    7-mercapto-heptanoylthreonine phosphate;    Pipes;    1;    4-piperazinediethanesulfonic acid;    Tricine;    N-[2-hydroxy-1;    1-bis(hydroxymethyl)ethyl]-glycine;   

DOI  :  10.1016/0014-5793(90)80670-E

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Washed membrane or cytoplasmic fractions of the methanogenic bacterium strain Göl catalyzed the oxidation of coenzyme F₄₂₀H₂ with a variety of electron acceptors. The F₄₂₀H₂-oxidizing activity of the cytoplasmic fraction could be assigned to a NADP⁺:F₄₂₀ oxidoreductase. The membrane fraction but not the cytoplasmic fraction catalyzed the oxidation of F₄₂₀H₂ with the concomitant reduction of the heterodisulfide of 2-mercapto-ethanesulfonate and 7-mercaptoheptanoylthreonine phosphate (CoM-S-S-HTP) at a rate of 100 protein according to the following equation: F₄₂₀H₂+CoM-S-S-HTP → F₄₂₀ + CoM + HTP-SH. The activity depended linearly on the membrane protein up to a concentration of 60 The physiological electron acceptor CoM-S-S-HTP could not be replaced by the corresponding homodisulfides CoM-S-S-CoM and HTP-S-S-HTP or by NADP⁺. A membrane-bound F₄₂₀H₂-dependent CoM-S-S-HTP reductase was also detected in Methanolobus tindarius exhibiting a specific activity of 75 protein. The absence of a F₄₂₀-dependent hydrogenase in this organism excludes the involvement of this enzyme in electron transfer from H₄₂₀H₂ to CoM-S-S-HTP.

【 授权许可】

Unknown