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1978
Moura, JJ, Xavier AV, Cammack R, Hall DO, Bruschi M, Legall J.  1978.  Oxidation-reduction studies of the Mo-(2Fe-2S) protein from Desulfovibrio gigas, Aug 1. Biochem J. 173:419-25., Number 2 AbstractWebsite

Potentiometric titration followed by e.p.r. measurements were used to determine the midpoint reduction potentials of the redox centres of a molybdenum-containing iron-sulphur protein previously isolated from Desulfovibrio gigas, a sulphate-reducing bacterium (Moura, Xavier, Bruschi, Le Gall, Hall & Cammack (1976) Biochem. Biophys. Res. Commun. 728 782-789; Moura, Xavier, Bruschi, Le Gall & Cabral (1977) J. Less Common Metals 54, 555-562). The iron-sulphur centres could readily be distinguished into three types by means of g values, temperature effect, oxidation-reduction potential values and reduction rates. The type-I Fe-S centres are observed at 77 K. They show mid-point potential values of -260mV (Fe-S type IA) and -440 mV (Fe-S type IB). Centres of types IA and IB appear to have similar spectra at 77 K and 24 K. The Fe-S type-II centres are only observed below 65 K and have a midpoint potential of -28mV. Long equilibration times (30 min) with dye mediators under reducing conditions were necessary to observe the very slow equilibrating molybdenum signals. The potential values associated with this signal were estimated to be approx. -415 mV for Mo(VI)/Mo(V) and-530mV for Mo(V)/Mo(IV).

Probst, I, Moura JJ, Moura I, Bruschi M, Legall J.  1978.  Isolation and characterization of a rubredoxin and an (8Fe-8S) ferredoxin from Desulfuromonas acetoxidans, Apr 11. Biochim Biophys Acta. 502:38-44., Number 1 AbstractWebsite

A two cluster (4Fe-4S) ferredoxin and a rubredoxin have been isolated from the sulfur-reducing bacterium Desulfuromonas acetoxidans. Their amino acid compositions are reported and compared to those of other iron-sulfur proteins. The ferredoxin contains 8 cysteine residues, 8 atoms of iron and 8 atoms of labile sulfur per molecule; its minimum molecular weight is 6163. The protein exhibits an abosrbance ratio of A385/A283 = 0.74. Storage results in a bleaching of the chromophore; the denatured ferredoxin is reconstitutable with iron and sulfide. The instability temperature is 52 degrees C. The rubredoxin does not differ markedly from rubredoxins from other anaerobic bacteria.

Moura, I, Xavier AV, Cammack R, Bruschi M, Legall J.  1978.  A comparative spectroscopic study of two non-haem iron proteins lacking labile sulphide from Desulphovibrio gigas. Biochimica et Biophysica Acta (BBA) - Protein Structure. 533:156-162., Number 1 AbstractWebsite
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1977
Cammack, R, Rao KK, Hall DO, Moura JJ, Xavier AV, Bruschi M, Legall J, Deville A, Gayda JP.  1977.  Spectroscopic studies of the oxidation-reduction properties of three forms of ferredoxin from Desulphovibrio gigas, Feb 22. Biochim Biophys Acta. 490:311-21., Number 2 AbstractWebsite

Electron paramagnetic resonance spectra were recorded of three forms of Desulphovibrio gigas ferredoxin, FdI, FdI' and FdII. The g = 1.94 signal seen in dithionite-reduced samples is strong in FdI, weaker in FdI' and very small in FdII. The g = 2.02 signal in the oxidized proteins is weak in FdI and strongest in FdII. It is concluded that most of the 4Fe-4S centres in FdI change between states C- and C2-; FdI' contain both types of centre. There is no evidence that any particular centre can change reversibly between all three oxidation states. Circular dichroism spectra show differences between FdI and FdII even in the diamagnetic C2- state. The redox potentials of the iron-sulphur centres of the three oligomers (forms) are different. After formation of the apo-protein of FdII and reconstitution with iron and sulphide, the protein behaves more like FdI, showing a strong g = 1.94 signal in the reduced states.

Moura, I, Bruschi M, Legall J, Moura JJ, Xavier AV.  1977.  Isolation and characterization of desulforedoxin, a new type of non-heme iron protein from Desulfovibrio gigas, Apr 25. Biochem Biophys Res Commun. 75:1037-44., Number 4 AbstractWebsite
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Moura, JJG, Xavier AV, Bruschi M, Legall J, Cabral JMP.  1977.  A molybdenum-containing (2Fe, 2S) protein from desulphovibrio gigas, a sulphate reducer. Journal of the Less Common Metals. 54:555-562., Number 2 AbstractWebsite
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1976
Moura, JJ, Xavier AV, Bruschi M, Legall J, Hall DO, Cammack R.  1976.  A molybdenum-containing iron-sulphur protein from Desulphovibrio gigas, Oct 4. Biochem Biophys Res Commun. 72:782-9., Number 3 AbstractWebsite
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Bruschi, M, Hatchikian C, Legall J, Moura JJ, Xavier AV.  1976.  Purification, characterization and biological activity of three forms of ferredoxin from the sulfate-reducing bacterium Desulfovibrio gigas, Nov 9. Biochim Biophys Acta. 449:275-84., Number 2 AbstractWebsite

Three forms of ferredoxin FdI, FdI', and FdII have been isolated from Desulfovibrio gigas, a sulfate reducer. They are separated by a combination of DEAE-cellulose and gel filtration chromatographic procedures. FdI and FdI' present a slight difference in isoelectric point which enables the separation of the two forms over DEAE-cellulose, while FdII is easily separated from the two other forms by gel filtration. The three forms have the same amino acid composition and are isolated in different aggregation states. Molecular weight determinations by gel filtration gave values of 18 000 for FdI and FdI' and 24 000 for FdII, whereas a value of 6000 is determined when dissociation is accomplished with sodium dodecyl sulfate. The electronic spectra are different and their ultraviolet-visible absorbance rations are 0.77, 0.87 and 0.68 respectively for FdI, FdI' and FdII. Despite these differences, the physiological activities of the three forms are similar as far as the reduction of sulfite by molecular hydrogen is concerned.

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