Isolation and Characterization of Methanophenazine and Function of Phenazines in Membrane-Bound Electron Transport of Methanosarcina Mazei Gö1

J Bacteriol. 1998 Apr;180(8):2027-32.

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 F42OH2 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 microM, 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Membrane / metabolism
  • Chromatography, High Pressure Liquid
  • Electron Transport
  • Kinetics
  • Mass Spectrometry
  • Methanosarcina / metabolism*
  • Models, Chemical
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Oxidoreductases / isolation & purification
  • Oxidoreductases / metabolism*
  • Phenazines / chemistry*
  • Phenazines / isolation & purification
  • Phenazines / metabolism*
  • Substrate Specificity

Substances

  • Phenazines
  • methanophenazine
  • F420H2 dehydrogenase
  • Oxidoreductases