Further redox reactions of metal clusters in the molybdenum-iron protein of Azotobacter vinelandii nitrogenase

Biochemistry ◽  
1986 ◽  
Vol 25 (18) ◽  
pp. 5196-5202 ◽  
Author(s):  
G. D. Watt ◽  
Z. Wang
Keyword(s):  
Redox Reactions ◽  
Metal Clusters ◽  
Azotobacter Vinelandii ◽  
Molybdenum Iron Protein ◽  
Iron Protein

Circular dichroism and magnetic circular dichroism of reduced molybdenum-iron protein of Azotobacter vinelandii nitrogenase

Biochemistry ◽  
1981 ◽  
Vol 20 (10) ◽  
pp. 2857-2864 ◽  
Author(s):  
P. J. Stephens ◽  
C. E. McKenna ◽  
M. C. McKenna ◽  
H. T. Nguyen ◽  
F. Devlin
Keyword(s):  
Circular Dichroism ◽  
Azotobacter Vinelandii ◽  
Magnetic Circular Dichroism ◽  
Molybdenum Iron Protein ◽  
Iron Protein ◽  
Circular Dichroïsm

scholarly journals The photoreduction of nitrogenase

1993 ◽  
Vol 290 (2) ◽  
pp. 627-631 ◽  
Author(s):  
Druzhinin SYu ◽  
L A Syrtsova ◽  
A M Uzenskaja ◽  
G I Likhtenstein
Keyword(s):  
Atpase Activity ◽  
Azotobacter Vinelandii ◽  
Electron Flux ◽  
Protein Component ◽  
Photochemical Reduction ◽  
Total Electron ◽  
Molybdenum Iron Protein ◽  
Iron Protein ◽  
Reduction Activity ◽  
Substrate Reduction

The photoreduction, without reductant dithionite, of N2 to NH3 or acetylene to ethylene catalysed by nitrogenase in the presence of Mg2+. ATP, eosin and NADH in the light has been established. There is an optimum NADH concentration for each particular eosin concentration. When the ratio of the iron protein component of nitrogenase from Azotobacter vinelandii (Av2)/the molybdenum-iron protein component of nitrogenase from A. vinelandii (Av1) is equal to 3 for 4 x 10(-5) M eosin the optimum NADH concentration is 5 x 10(-4) M. The rate of photoreduction (per one electron) of acetylene or N2 under identical conditions was shown to be similar. The photoreductant-dependent ATPase activity, in the presence of a given photochemical system in the light, was revealed. Eosin is shown to be the inhibitor of the coupling site. Concentrations of 8 x 10(-6) -1 x 10(-4) M eosin do not inhibit the ATPase activity. The inhibition of substrate-reduction activity depends on the ratio of the nitrogenase components. Under conditions where the Av2/Av1 ratio is equal to 1 the rate of photochemical reduction is higher than in the presence of dithionite: the total electron flux through nitrogenase being increased 2.2-fold. We suggest that in this case the nitrogenase complex (1:1) works without dissociation.

scholarly journals The molecular weight of, and evidence for two types of subunits in, the molybdenum-iron protein of Azotobacter vinelandii nitrogenase

1977 ◽  
Vol 163 (3) ◽  
pp. 427-432 ◽  
Author(s):  
R H Swisher ◽  
M L Landt ◽  
F J Reithel
Keyword(s):  
Molecular Weight ◽  
Azotobacter Vinelandii ◽  
Average Molecular Weight ◽  
Amino Acid Content ◽  
Sedimentation Equilibrium ◽  
Weight Average Molecular Weight ◽  
Molybdenum Iron Protein ◽  
Iron Protein ◽  
Molecular Weights ◽  
Fe Protein

The weight-average molecular weight of the Mo-Fe protein isolated from Azotobacter vinelandii has been determined by sedimentation-equilibrium techniques. In buffer, the value is 245000+/-5000; in 8M-urea, the value is 61000+/-1000. The protein was separated into two components by chromatography on CM-cellulose in 7M-urea, pH 4.5. These components have similar molecular weights but were shown to differ in charge, amino acid content and arginine-containing peptides. It is proposed that the tetramer has the subunit composition (nalpha2nbeta2).

Redox reactions of and nucleotide binding to the iron protein of Azotobacter vinelandii

Biochemistry ◽  
1986 ◽  
Vol 25 (25) ◽  
pp. 8156-8162 ◽  
Author(s):  
G. D. Watt ◽  
Z. C. Wang ◽  
R. R. Knotts
Keyword(s):  
Redox Reactions ◽  
Azotobacter Vinelandii ◽  
Nucleotide Binding ◽  
Iron Protein
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