Redox thermodynamics of low-potential iron-sulfur proteins

Redox Control of the Human Iron-Sulfur Repair Protein MitoNEET Activity via Its Iron-Sulfur Cluster.

Human mitoNEET (mNT) is the first identified Fe-S protein of the mammalian outer mitochondrial membrane. Recently, mNT has been implicated in cytosolic Fe-S repair of a key regulator of cellular iron homeostasis. Here, we aimed to decipher the mechanism by which mNT triggers its Fe-S repair capacity. By using tightly controlled reactions combined with complementary spectroscopic approaches, we ...

Ferredoxins from Bacillus polymyxa. Low potential iron-sulfur proteins which appear to contain single four iron, four sulfur centers accepting a single electron on reduction.

Two iron-sulfur proteins from Bacillus polymyxa (ferredoxins I and II) have been shown to transfer 1 electron per 4 iron atoms at a potential of -380 and -420 mv, respectively, at pH 7. The proteins contain 4 iron and 4 labile sulfur atoms and 4 cysteine residues in molecules of about 9,000 daltons; electron paramagnetic resonance and optical properties suggest that each contains an iron-sulfur...

Iron-sulfur proteins: spin-coupling model for three-iron clusters.

Recent Mössbauer and EPR studies of two ferredoxins and of aconitase have given evidence for a three-iron cluster, probably of a [3Fe-3S] type. The studies of the oxidized EPR-active centers have shown that the three iron sites are characterized by significantly different magnetic hyperfine coupling constants. For the ferredoxin from Azotobacter vinelandii, for instance, we have observed A1 = -...

Metalloproteins Containing Cytochrome, Iron–Sulfur, or Copper Redox Centers

Atomic resolution structures of rieske iron-sulfur protein: role of hydrogen bonds in tuning the redox potential of iron-sulfur clusters.

The Rieske [2Fe-2S] iron-sulfur protein of cytochrome bc(1) functions as the initial electron acceptor in the rate-limiting step of the catalytic reaction. Prior studies have established roles for a number of conserved residues that hydrogen bond to ligands of the [2Fe-2S] cluster. We have constructed site-specific variants at two of these residues, measured their thermodynamic and functional p...