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J Bacteriol, April 1998, p. 2027-2032, Vol. 180, No. 8
Institut für Mikrobiologie und
Genetik1 and
Institut für
Organische Chemie,2
Georg-August-Universität, 37077 Göttingen, Germany
Received 5 November 1997/Accepted 2 February 1998
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 F420H2 dehydrogenase
from M. mazei Gö1 showed highest activity with
2-hydroxyphenazine and 2-bromophenazine as electron acceptors when
F420H2 was added. Phenazine-1-carboxylic acid
and phenazine proved to be less effective. The
Km values for 2-hydroxyphenazine and phenazine
were 35 and 250 µM, respectively. 2-Hydroxyphenazine was also reduced
by molecular hydrogen catalyzed by an F420-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.
0021-9193/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Isolation and Characterization of Methanophenazine
and Function of Phenazines in Membrane-Bound Electron Transport of
Methanosarcina mazei Gö1
*
Corresponding author. Mailing address: Institut
für Mikrobiologie und Genetik, Universität Göttingen,
Grisebachstr. 8, 37077 Göttingen, Germany. Phone: (49) 551 393812. Fax: (49) 551 393793. E-mail: udeppen{at}gwdg.de.
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