TY - JOUR
T1 - Two W-containing formate dehydrogenases (CO2-reductases) involved in syntrophic propionate oxidation by Syntrophobacter fumaroxidans
AU - De Bok, Frank A.M.
AU - Hagedoorn, Peter Leon
AU - Silva, Pedro J.
AU - Hagen, Wilfred R.
AU - Schiltz, Emile
AU - Fritsche, Kathrin
AU - Stams, Alfons J M
PY - 2003
Y1 - 2003
N2 - Two formate dehydrogenases (CO2-reductases) (FDH-1 and FDH-2) were isolated from the syntrophic propionate-oxidizing bacterium Syntrophobacter fumaroxidans. Both enzymes were produced in axenic fumarate-grown cells as well as in cells which were grown syntrophically on propionate with Methanospirillum hungatei as the H2 and formate scavenger. The purified enzymes exhibited extremely high formate-oxidation and CO2-reduction rates, and low Km values for formate. For the enzyme designated FDH-1, a specific formate oxidation rate of 700 U·mg-1 and a Km for formate of 0.04 mM were measured when benzyl viologen was used as an artificial electron acceptor. The enzyme designated FDH-2 oxidized formate with a specific activity of 2700 U·mg-1 and a Km of 0.01 mM for formate with benzyl viologen as electron acceptor. The specific CO2-reduction (to formate) rates measured for FDH-1 and FDH-2, using dithionite-reduced methyl viologen as the electron donor, were 900 U·mg-1 and 89 U·mg-1, respectively. From gel filtration and polyacrylamide gel electrophoresis it was concluded that FDH-1 is composed of three subunits (89 ± 3, 56 ± 2 and 19 ± 1 kDa) and has a native molecular mass of approximately 350 kDa. FDH-2 appeared to be a heterodimer composed of a 92 ± 3 kDa and a 33 ± 2 kDa subunit. Both enzymes contained tungsten and selenium, while molybdenum was not detected. EPR spectroscopy suggested that FDH-1 contains at least four [2Fe-2S] clusters per molecule and additionally paramagnetically coupled [4Fe-4S] clusters. FDH-2 contains at least two [4Fe-4S] clusters per molecule. As both enzymes are produced under all growth conditions tested, but with differences in levels, expression may depend on unknown parameters.
AB - Two formate dehydrogenases (CO2-reductases) (FDH-1 and FDH-2) were isolated from the syntrophic propionate-oxidizing bacterium Syntrophobacter fumaroxidans. Both enzymes were produced in axenic fumarate-grown cells as well as in cells which were grown syntrophically on propionate with Methanospirillum hungatei as the H2 and formate scavenger. The purified enzymes exhibited extremely high formate-oxidation and CO2-reduction rates, and low Km values for formate. For the enzyme designated FDH-1, a specific formate oxidation rate of 700 U·mg-1 and a Km for formate of 0.04 mM were measured when benzyl viologen was used as an artificial electron acceptor. The enzyme designated FDH-2 oxidized formate with a specific activity of 2700 U·mg-1 and a Km of 0.01 mM for formate with benzyl viologen as electron acceptor. The specific CO2-reduction (to formate) rates measured for FDH-1 and FDH-2, using dithionite-reduced methyl viologen as the electron donor, were 900 U·mg-1 and 89 U·mg-1, respectively. From gel filtration and polyacrylamide gel electrophoresis it was concluded that FDH-1 is composed of three subunits (89 ± 3, 56 ± 2 and 19 ± 1 kDa) and has a native molecular mass of approximately 350 kDa. FDH-2 appeared to be a heterodimer composed of a 92 ± 3 kDa and a 33 ± 2 kDa subunit. Both enzymes contained tungsten and selenium, while molybdenum was not detected. EPR spectroscopy suggested that FDH-1 contains at least four [2Fe-2S] clusters per molecule and additionally paramagnetically coupled [4Fe-4S] clusters. FDH-2 contains at least two [4Fe-4S] clusters per molecule. As both enzymes are produced under all growth conditions tested, but with differences in levels, expression may depend on unknown parameters.
KW - Formate
KW - Interspecies hydrogen transfer
KW - Methanogenesis
KW - Syntrophy
KW - Tungstoenzymes
UR - http://www.scopus.com/inward/record.url?scp=0038054187&partnerID=8YFLogxK
U2 - 10.1046/j.1432-1033.2003.03619.x
DO - 10.1046/j.1432-1033.2003.03619.x
M3 - Article
C2 - 12755703
AN - SCOPUS:0038054187
SN - 0014-2956
VL - 270
SP - 2476
EP - 2485
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
IS - 11
ER -