Journalartikel

Jahr der Veröffentlichung: 2004

Seiten: 2451-2463

Zeitschrift: Microbiology

Bandnummer: 150

ISSN: 1350-0872

eISSN: 1465-2080

Open Access Status: Bronze

DOI Link: https://doi.org/10.1099/mic.0.27159-0

Verlag: Microbiology Society

Abstract: 
Thermoanaerobacter tengcongensis is a thermophilic Gram-positive bacterium able to dispose of the reducing equivalents generated during the fermentation of glucose to acetate and CO2 by reducing H+ to H-2. A unique combination of hydrogenases, a ferredoxin-dependent [NiFe] hydrogenase and an NADH-dependent Fe-only hydrogenase, were found to be responsible for H-2 formation in this organism. Both enzymes were purified and characterized. The tightly membrane-bound [NiFe] hydrogenase belongs to a small group of complex-I-related [NiFe] hydrogenases and has highest sequence similarity to energy-converting [NiFe] hydrogenase (Ech) from Methanosarcina barkeri. A ferredoxin isolated from Ta. tengcongensis was identified as the physiological substrate of this enzyme. The heterotetrameric Fe-only hydrogenase was isolated from the soluble fraction. It contained FMN and multiple iron-sulfur clusters, and exhibited a typical H-cluster EPR signal after autooxidation. Sequence analysis predicted and kinetic studies confirmed that the enzyme is an NAD(H)-dependent Fe-only hydrogenase. When H-2 was allowed to accumulate in the culture, the fermentation was partially shifted to ethanol production. In cells grown at high hydrogen partial pressure [p(H-2)] the NADH-dependent hydrogenase activity was fourfold lower than in cells grown at low p(H-2), whereas aldehyde dehydrogenase and alcohol dehydrogenase activities were higher in cells grown at elevated p(H-2). These results indicate a regulation in response to the p(H-2).

Harvard-Zitierstil: Soboh, B., Linder, D. and Hedderich, R. (2004) A multisubunit membrane-bound [NiFe] hydrogenase and an NADH-dependent Fe-only hydrogenase in the fermenting bacterium Thermoanaerobacter tengcongensis, Microbiology, 150, pp. 2451-2463. https://doi.org/10.1099/mic.0.27159-0

APA-Zitierstil: Soboh, B., Linder, D., & Hedderich, R. (2004). A multisubunit membrane-bound [NiFe] hydrogenase and an NADH-dependent Fe-only hydrogenase in the fermenting bacterium Thermoanaerobacter tengcongensis. Microbiology. 150, 2451-2463. https://doi.org/10.1099/mic.0.27159-0