1995
DOI: 10.1111/j.1432-1033.1995.0811a.x
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Reversible Super‐Reduction of the Cubane [4Fe‐4S](3+;2+;1+) in the High‐Potential Iron‐Sulfur Protein Under Non‐Denaturing Conditions

Abstract: The reversible 2x1 e-reduction of the cubane cluster from oxidized to reduced to super-reduced states ([4Fe-4S]"*[4Fe-4S]'+~[4Fe-4S]'+) was studied in high-potential iron-sulfur proteins (HiPIPs).Super-reduction to the 1 + state was not observed in any of the seven HiPIPs tested during cyclic voltammetry (down to -0.95 V). However, equilibration at low potential (pH 7.5) of Rhodopila globiformis HiPIP yields a transient peak around -0.47 V due to the oxidation of super-reduced HiPIP adsorbed at the electrode. … Show more

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Cited by 13 publications
(9 citation statements)
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“…The reduction potential for the 1‐/2‐ couple of the Fds and FePs is presumably so positive that it is not generally accessible by experiment and has been measured as 0.73 V for Clostridium pasteurianum Fd 57. Similarly, the reduction potential for the 2‐/3‐ couple of HiPIPs is presumably so negative that it is also not generally accessible and has been measured as −0.91 V for Rhodopila globiformis HiPIP 56. The reduction potentials calculated by DFT and PB [Eq.…”
Section: Resultsmentioning
confidence: 99%
See 1 more Smart Citation
“…The reduction potential for the 1‐/2‐ couple of the Fds and FePs is presumably so positive that it is not generally accessible by experiment and has been measured as 0.73 V for Clostridium pasteurianum Fd 57. Similarly, the reduction potential for the 2‐/3‐ couple of HiPIPs is presumably so negative that it is also not generally accessible and has been measured as −0.91 V for Rhodopila globiformis HiPIP 56. The reduction potentials calculated by DFT and PB [Eq.…”
Section: Resultsmentioning
confidence: 99%
“…In addition, as two structures of Av FeP were solved at the same resolution with the same R ‐factor, their results were also averaged. The experimental reduction potentials in the HiPIPs for 1‐/2‐42, 54, 55 and the 2‐/3‐56 couples, in the Fds for the 1‐/2‐57 and 2‐/3‐ couples,46, 58, 59 and the FePs for the 2‐/3‐60, 61 couple were obtained from the literature. The value for the 1‐/2‐ couple of the FePs is assumed based on the value for the 2‐/3‐.…”
Section: Methodsmentioning
confidence: 99%
“…This observation is consistent with the proposition (20,21) that the two oxidation processes associated with the proximal cluster of these enzymes may be assigned to 3FeðIIÞ-1FeðIIIÞ → 2FeðIIÞ-2FeðIIIÞ and 2FeðIIÞ-2FeðIIIÞ → 1FeðIIÞ-3FeðIIIÞ changes. Remarkably, the two redox couples lie within a narrow potential range when compared to that observed for the high-potential iron-sulfur protein (HiPIP), which is about 1 V and involves nonphysiological superreduction of the [4Fe-4S] cluster to the +1 oxidation level (22,23).…”
mentioning
confidence: 99%
“…39,40 The initial description of`superreduced' HiPIP demonstrated production of a paramagnetic resonance with the properties of the fully reduced species at high pH in the presence of dimethyl sulfoxide and was assumed, without supporting evidence, to imply that the polypeptide was itself in a non-native state. More recent evidence in aqueous solutions with titanium(III) citrate as reductant 18 points to the importance of high pH, as noted earlier. 19 These studies suggest that some alteration of the native polypeptide structure is involved, but the extent of such alteration has not been determined.…”
Section: Oxidation-reduction Potentialsmentioning
confidence: 86%