Azotobacter vinelandii ferredoxin

Fig. 13. Representative Trumpet Plots for the [3Fe-4S]+/0 couple in native and D15N mutant forms of Azotobacter vinelandii ferredoxin I adsorbed on a PGE electrode. The plots for D15N also show the fits based on k0 t = 2.5 s-1. Note the intermediate region of the plot (pH 5.50) in which an oxidation peak is not observed because ET is gated. Data points shown in red are for the pH values indicated whereas data points shown in blue are for the uncoupled electron-transfer reaction occurring at pH > pffoiuater- Reproduced from Ref. (33) by permission of the Royal Society of Chemistry.

Three-iron clusters. Despite the availability of an X-ray crystallographic structure determination of Azotobacter vinelandii ferredoxin I (27), which contains both a normal 4Fe-4S cluster and a 3Fe cluster, the fundamental properties and even the structures... 

B.K., Stout, C.D., Hirst, )., and Armstrong, F.A. (2003) Mechanisms of redox-coupled proton transfer in proteins role of the proximal proline in reactions of the [3fe-4s] cluster in azotobacter vinelandii ferredoxin i. Biochemistry, 42, 10589. 

The last class of iron-sulfur proteins to be considered is that of the bacterial 7Fe ferredoxins, which contain both an Fe3S4 and an Fe4S4 cluster. Figure 28 shows the molecular structure of that from Azotobacter vinelandii (FW — 12 700).53... 

Figure 28 X-Ray structure of the active site of the 7Fe ferredoxin of Azotobacter vinelandii...

In confirmation of the chemical and electrochemical reversibility of these processes, the one-electron reduced complex of the 7Fe ferredoxin of Azotobacter vinelandii has been structurally characterized. The Fe3S4 cluster, on which the first reduction is centred, maintains a quasi-cuboidal geometry essentially unaltered with respect to the oxidized form some minor structural variation is observed on the peripheral amino acids.55... 

Figure 10.3 Crystallographic structures of the most important iron-sulphur centres in proteins (a) dimeric centre of ferrodoxin from Spinacia oleracea [54], (b) trimeric centre of ferredoxin from Bacillus schlegelii [55], (c) cubane cluster of nitrogenase reductase from Azotobacter vinelandii [56], (d) nitrogenase octameric cluster from Azotobacter vinelandii [57], (e) nitrogenase octameric cluster from Clostridium pasteurianum [58], (f) MoFe cluster of nitrogenase from Azotobacter vinelandii [59], and (g) active centre of sulphite reductase from Escherichia coli [60]...

The 3Fe center was first recognized " in the protein ferredoxin I from the anaerobic nitrogen-fixing h ct uava Azotobacter vinelandii. The protein is called Av Fdl for short. It is instructive to sketch historically the evolution of our understanding of this protein. Av ferredoxin I was reported to have 6 to 8 Fe... 

Although we have focused on individual structural units in rubredoxins, ferredoxins and HIPIPs, we should note that some metalloproteins contain more than one Fe S unit. For example, the ferredoxin isolated from Azotobacter vinelandii contains both [4Fe S] and [3Fe-4S] units, with the closest Fe-"-Fe separation between units being i930 pm. 

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