In:
Journal of Bacteriology, American Society for Microbiology, Vol. 180, No. 8 ( 1998-04-15), p. 2027-2032
Abstract:
A hydrophobic, redox-active component with a molecular mass of 538 Da was isolated from lyophilized membranes of Methanosarcina mazei Gö1 by extraction with isooctane. After purification on a high-performance liquid chromatography column, the chemical structure was analyzed by mass spectroscopy and nuclear magnetic resonance studies. The component was called methanophenazine and represents a 2-hydroxyphenazine derivative which is connected via an ether bridge to a polyisoprenoid side chain. Since methanophenazine was almost insoluble in aqueous buffers, water-soluble phenazine derivatives were tested for their ability to interact with membrane-bound enzymes involved in electron transport and energy conservation. The purified F 420 H 2 dehydrogenase from M. mazei Gö1 showed highest activity with 2-hydroxyphenazine and 2-bromophenazine as electron acceptors when F 420 H 2 was added. Phenazine-1-carboxylic acid and phenazine proved to be less effective. The K m values for 2-hydroxyphenazine and phenazine were 35 and 250 μM, respectively. 2-Hydroxyphenazine was also reduced by molecular hydrogen catalyzed by an F 420 -nonreactive hydrogenase which is present in washed membrane preparations. Furthermore, the membrane-bound heterodisulfide reductase was able to use reduced 2-hydroxyphenazine as an electron donor for the reduction of CoB-S-S-CoM. Considering all these results, it is reasonable to assume that methanophenazine plays an important role in vivo in membrane-bound electron transport of M. mazei Gö1.
Type of Medium:
Online Resource
ISSN:
0021-9193
,
1098-5530
DOI:
10.1128/JB.180.8.2027-2032.1998
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
1998
detail.hit.zdb_id:
1481988-0
SSG:
12
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