Redox characteristics of the tungsten DMSO reductase of Rhodobacter capsulatus.
The dimethylsulfoxide reductase (DMSOR) from Rhodobacter capsulatus is known to retain its three-dimensional structure and enzymatic activity upon substitution of molybdenum, the metal that occurs naturally at the active site, by tungsten. The redox properties of tungsten-substituted DMSOR (W-DMSOR) have been investigated by a dye-mediated reductive titration with the concentration of the W(V) state monitored by EPR spectroscopy. At pH 7.0, E(m)(W(VI)/W(V)) is -194 mV and E(m)(W(V)/W(IV)) is -134 mV. Each E(m) value of W-DMSOR is significantly lower (220 and 334 mV, respectively) than that of the corresponding couple of Mo-DMSOR. These redox potentials are consistent with the ability of Mo-DMSOR to catalyze both the reduction of DMSO to DMS and the back reaction, whereas W-DMSOR is very effective in catalyzing the forward reaction, but shows no ability to catalyze the oxidation of DMS to DMSO.
Hagedoorn
Peter Leon
PL
Kluyver Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, The Netherlands. p.l.hagedoorn@tnw.tudelft.nl
Hagen
Wilfred R
WR
Stewart
Lisa J
LJ
Docrat
Arefa
A
Bailey
Susan
S
Garner
C David
CD
D002384:Catalysis; D004121:Dimethyl Sulfoxide / Q000737:chemistry / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D007506:Iron-Sulfur Proteins; D008982:Molybdenum / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D016354:Rhodobacter capsulatus / Q000201:enzymology*; D017186:Titrimetry / Q000379:methods; D014414:Tungsten / Q000737:chemistry* / Q000378:metabolism
D007506:Iron-Sulfur Proteins; D008982:Molybdenum; D010088:Oxidoreductases; C045664:dimethyl sulfoxide reductase; D014414:Tungsten; D004121:Dimethyl Sulfoxide