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Resonance Raman spectra of three-iron centers in ferredoxins from Desulfovibrio gigas, Johnson, M. K., Hare J. W., Spiro T. G., Moura J. J., Xavier A. V., and Legall J. , J Biol Chem, Oct 10, Volume 256, Number 19, p.9806-8, (1981) AbstractWebsite

The resonance Raman spectra of ferredoxins (Fd) I and II from Desulfovibrio gigas are reported using 4579 A Ar+ laser excitation. The (3Fe-3S) center in Fd II has a characteristic resonance Raman spectrum, readily distinguishable from those of (2Fe-2S) or (4Fe-4S) clusters. Reduction of Fd II produces a marked alteration in the resonance Raman spectrum. Fd I is shown to contain both (3Fe-3S) and (4Fe-4S) Fd-type clusters. The results illustrate the potential of resonance Raman spectroscopy in Fe-S cluster identification, even in cases where more than one cluster type is present.

Conversion of [3 Fe-3 S] into [4 Fe-4 S] clusters in a Desulfovibrio gigas ferredoxin and isotopic labeling of iron—sulfur cluster subsites, Kent, T. A., Moura I., Moura J. J. G., Lipscomb J. D., Huynh B. H., Legall J., Xavier A. V., and Münck E. , Febs Letters, Volume 138, Number 1, p.55-58, (1982) AbstractWebsite
Three-iron clusters in iron--sulfur proteins: An EPR study of the exchange interactions, Gayda, Jean-Pierre, Bertrand Patrick, Theodule Francois-Xavier, and Moura Jose J. G. , The Journal of Chemical Physics, Volume 77, Number 7, p.3387-3391, (1982) AbstractWebsite
Role of vitamin B12 in methyl transfer for methane biosynthesis by Methanosarcina barkeri, Wood, J. M., Moura I., Moura J. J., Santos M. H., Xavier A. V., Legall J., and Scandellari M. , Science, Apr 16, Volume 216, Number 4543, p.303-5, (1982) AbstractWebsite

When Methanosarcina barkeri is grown on methanol as the sole carbon source, a B12-containing protein is synthesized by this organism. This B12 protein contains bound aquocobalamin, and when this cofactor is reduced and methylated with [14C]methyl iodide, the resultant [14C]methyl B12 protein is extremely active in the biosynthesis of 14C-labeled methane. These findings indicate that a B12-dependent system is operative in the biological formation of methane in addition to other systems that are B12-independent.

Ferredoxin from Methanosarcina barkeri: evidence for the presence of a three-iron center, Moura, I., Moura J. J., Huynh B. H., Santos H., Legall J., and Xavier A. V. , Eur J Biochem, Aug, Volume 126, Number 1, p.95-8, (1982) AbstractWebsite

Methanosarcina barkeri ferredoxin was purified and characterized by electron paramagnetic resonance (EPR) and Mossbauer spectroscopy. The purification procedure included chromatographic steps on DEAE-cellulose and gel filtration. The isolated protein is unstable under aerobic conditions. The ferredoxin exhibits charge transfer bands at 283 nm and 405 nm with an absorption ratio A405/A283 = 0.73. Its molecular weight has been estimated to be 20000-22000 by gel filtration chromatography. The native ferredoxin exhibits an intense EPR signal at g = 2.02 and only a very weak g = 1.94 signal develops upon reduction with dithionite. The Mossbauer spectra of the reduced protein are characteristic of a [3Fe-3S] center. The combined EPR and Mossbauer studies show that M. barkeri ferredoxin contains only [3Fe-3S] clusters, similar to Azotobacter vinelandii Fd[Emptage, M.H., Kent, T.A., Huynh, B.H., Rawlings, J., Orme-Johnson, W.H. & Munck, M. (1980) J. Biol. Chem. 255, 1793-1796], Desulfovibrio gigas FdII [Huynh, B.H., Moura, J.J.G., Moura, I., Kent, T.A., LeGall, J., Xavier, A.V. & Munck, E. (1980) J. Biol. Chem. 255, 3242-3244] and mitochondrial beef heart aconitase [Kent, T.A., Dreyer, J.-L., Kennedy, M.C., Huynh, B.H., Emptage, M.H., Beinert, H. & Munck, E. (1982) Proc. Natl Acad. Sci. USA, 79, 1096-1100].

Mossbauer and EPR studies on nitrite reductase from Thiobacillus denitrificans, Huynh, B. H., Lui M. C., Moura J. J., Moura I., Ljungdahl P. O., Munck E., Payne W. J., Peck, H. D. Jr., Dervartanian D. V., and Legall J. , J Biol Chem, Aug 25, Volume 257, Number 16, p.9576-81, (1982) AbstractWebsite
Amino acid sequence of a 3Fe:3S ferredoxin from the "archaebacterium" Methanosarcina barkeri (DSM 800), Hausinger, R. P., Moura I., Moura J. J., Xavier A. V., Santos M. H., Legall J., and Howard J. B. , J Biol Chem, Dec 10, Volume 257, Number 23, p.14192-7, (1982) AbstractWebsite

The complete amino acid sequence for a 3Fe:3S ferredoxin from the "archaebacterium" Methanosarcina barkeri (DSM 800) was determined by repetitive Edman degradation on the whole protein and peptides derived from trypsin, thermolysin, and Staphylococcus aureus protease digestion. The protein has 59 residues of which 8 are cysteines. The latter have the same spacing and distribution as found for the clostridial-type 2 x 4Fe:4S ferredoxins. Also, the sequence had evidence of internal homology which is indicative of gene duplication prior to the divergence of the archaebacteria and the eubacteria. This is the first sequence to be reported for a methanogen ferredoxin and only the fourth for a 3Fe:3S ferredoxin from any source.

Evidence for nickel and a three-iron center in the hydrogenase of Desulfovibrio desulfuricans, Kruger, H. J., Huynh B. H., Ljungdahl P. O., Xavier A. V., Dervartanian D. V., Moura I., Peck, H. D. Jr., Teixeira M., Moura J. J., and Legall J. , J Biol Chem, Dec 25, Volume 257, Number 24, p.14620-3, (1982) AbstractWebsite

Hydrogenase from Desulfovibrio desulfuricans (ATCC No. 27774) grown in unenriched and in enriched 61Ni and 57Fe media has been purified to apparent homogeneity. Two fractions of enzymes with hydrogenase activity were separated and were termed hydrogenase I and hydrogenase II. they were shown to have similar molecular weights (77,600 for hydrogenase I and 75,500 for hydrogenase II), to be composed of two polypeptide chains, and to contain Ni and non-heme iron. Because of its higher specific activity (152 versus 97) hydrogenase II was selected for EPR and Mossbauer studies. As isolated, hydrogenase II exhibits an "isotropic" EPR signal at g = 2.02 and a rhombic EPR signal at g = 2.3, 2.2, and 2.0. Isotopic substitution of 61Ni proves that the rhombic signal is due to Ni. Combining the Mossbauer and EPR data, the isotropic g = 2.02 EPR signal was shown to originate from a 3Fe cluster which may have oxygenous or nitrogenous ligands. In addition, the Mossbauer data also revealed two [4Fe-4S]2+ clusters iun each molecule of hydrogenase II. The EPR and Mossbauer data of hydrogenase I were found to be identical to those of hydrogenase II, indicating that both enzymes have common metallic centers.

Interconversions of [3Fe-3S] and [4Fe-4S] clusters. Mossbauer and electron paramagnetic resonance studies of Desulfovibrio gigas ferredoxin II, Moura, J. J., Moura I., Kent T. A., Lipscomb J. D., Huynh B. H., Legall J., Xavier A. V., and Munck E. , J Biol Chem, Jun 10, Volume 257, Number 11, p.6259-67, (1982) AbstractWebsite
Incorporation of cytoplasmic vesicles into apical membrane of mammalian urinary bladder epithelium, Lewis, S. A., and de Moura J. L. , Nature, Jun 24, Volume 297, Number 5868, p.685-8, (1982) AbstractWebsite
Core dimensions in the 3Fe cluster of Desulfovibrio gigas ferredoxin II by extended X-ray absorption fine structure spectroscopy, Antonio, M. R., Averill B. A., Moura I., Moura J. J., Orme-Johnson W. H., Teo B. K., and Xavier A. V. , J Biol Chem, Jun 25, Volume 257, Number 12, p.6646-9, (1982) AbstractWebsite

We have obtained the iron K-edge extended X-ray adsorption fine structure spectra of the 3Fe ferredoxin II of Desulfovibrio gigas in the oxidized and reduced states. For both states, interpretation of the EXAFS data suggests that the Fe-S first shell coordination distance is near 2.25 A, in agreement with crystallographic studies of model compounds and proteins containing 2Fe-2S and 4Fe-4S centers, as well as with a recent crystallographic study of Azotobacter vinelandii ferredoxin I (Ghosh, D., Furey, W., Jr., O'Donnell, S., and Stout, C. D. (1981) J. Biol. Chem. 256, 4185-4192). The apparent Fe-Fe distance we obtain for the desulfovibrio protein (2.7 A) also agrees with similar distances seen in other Fe-S centers, except with the 3Fe cluster in the Azotobacter vinelandii ferredoxin I structure, for which an Fe-Fe distance of 4.2 A was reported. We conclude that either the two 3Fe ferredoxins have substantially different core dimensions, a possibility apparently unique to 3Fe centers among known Fe-S systems in proteins, or that one (or more) of the structural studies is in substantial error.

Iron-sulphur cluster composition and redox properties of two ferredoxins from Desulfovibrio desulfuricans Norway strain, Guerlesquin, F., Moura J. J., and Cammack R. , Biochim Biophys Acta, Mar 16, Volume 679, Number 3, p.422-7, (1982) AbstractWebsite

Two ferredoxins from Desulfovibrio desulfuricans, Norway Strain, were investigated by EPR spectroscopy. Ferredoxin I appears to be a conventional [4Fe-4S]2+;1+ ferredoxin, with a midpoint reduction potential of -374 mV at pH 8. Ferredoxin II when reduced, at first showed a more complex spectrum, indicating an interaction between two [4Fe-4S] clusters, and probably, has two clusters per protein subunit. Upon reductive titration ferredoxin II changed to give a spectrum in which no intercluster interaction was seen. The midpoint potentials of the native and modified ferredoxin at pH 8 were estimated to be -500 and -440 mV, respectively.

The presence of redox-sensitive nickel in the periplasmic hydrogenase from Desulfovibrio gigas, Legall, J., Ljungdahl P. O., Moura I., Peck, H. D. Jr., Xavier A. V., Moura J. J., Teixera M., Huynh B. H., and Dervartanian D. V. , Biochem Biophys Res Commun, May 31, Volume 106, Number 2, p.610-6, (1982) AbstractWebsite
Isolation of P590 from Methanosarcina barkeri: evidence for the presence of sulfite reductase activity, Moura, J. J., Moura I., Santos H., Xavier A. V., Scandellari M., and Legall J. , Biochem Biophys Res Commun, Oct 15, Volume 108, Number 3, p.1002-9, (1982) AbstractWebsite
Unambiguous identification of the nickel EPR signal in 61Ni-enriched Desulfovibrio gigas hydrogenase, Moura, J. J., Moura I., Huynh B. H., Kruger H. J., Teixeira M., DuVarney R. C., Dervartanian D. V., Xavier A. V., Peck, H. D. Jr., and Legall J. , Biochem Biophys Res Commun, Oct 29, Volume 108, Number 4, p.1388-93, (1982) AbstractWebsite
NMR redox studies of Desulfovibrio vulgaris Cytochrome c3. Electron transfer mechanisms, Moura, J. J., Santos H., Moura I., Legall J., Moore G. R., Williams R. J., and Xavier A. V. , Eur J Biochem, Sep, Volume 127, Number 1, p.151-5, (1982) AbstractWebsite

The 300-MHz proton NMR spectra of the tetrahaem cytochrome c3 from Desulfovibrio vulgaris were examined while varying the pH and the redox potential. The analysis of the complete NMR reoxidation pattern was done taking into account all the 16 redox states that can be present in the redox titration of a tetra-redox-center molecule. A network of saturation transfer experiments performed at different oxidation stages, between the fully reduced and the fully oxidized states, allowed the observation of different resonances for some of the haem methyl groups. In the present experimental conditions, some of the haems show a fast intramolecular electron exchange rate, but the intermolecular electron exchange is always slow. In intermediate reoxidation stages, large shifts of the resonances of some haem methyl groups were observed upon changing the pH. These shifts are discussed in terms of a pH dependence of the haem midpoint redox potentials. The physiological relevance of this pH dependence is discussed.

Electron transfer mechanism studies of cytochrome c3: pH dependence of the redox equilibria, Santos, H., Moura J. J. G., Xavier A. V., and Legall J. , Inorganica Chimica Acta, Volume 79, p.167-169, (1983) AbstractWebsite
Mössbauer and EPR evidence for nickel and 3Fe cluster in the hydrogenases of D. desulfuricans and D. gigas, Huynh, B. H., Legall J., Dervartanian D. V., Peck Jr H. D., Krüger H. J., Moura I., Moura J. J. G., and Xavier A. V. , Inorganica Chimica Acta, Volume 79, p.136, (1983) AbstractWebsite
Nickel containing hydrogenases, Xavier, A. V., Teixeira M., Moura I., Moura J. J. G., and Legall J. , Inorganica Chimica Acta, Volume 79, p.13-14, (1983) AbstractWebsite
Proteins containing the factor F430 from methanosarcina barkeri and methanobacterium thermoautotrophicum: Isolation and properties, Moura, Isabel, Moura José J. G., Santos Helena, Xavier Antonio V., Burch Gary, Peck Jr Harry D., and Legall Jean , Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, Volume 742, Number 1, p.84-90, (1983) AbstractWebsite
Resonance Raman spectra of rubredoxin, desulforedoxin, and the synthetic analog Fe(S2-o-xyl)2: conformational effects, Yachandra, Vittal K., Hare Jeffrey, Moura I., and Spiro Thomas G. , Journal of the American Chemical Society, 1983/10/01, Volume 105, Number 21, p.6455-6462, (1983) AbstractWebsite
Desulfovibrio Gigas hydrogenase: redox properties of the nickel and iron-sulfur centers, Teixeira, M., Moura I., Xavier A. V., Dervartanian D. V., Legall J., Peck, H. D. Jr., Huynh B. H., and Moura J. J. , Eur J Biochem, Feb 15, Volume 130, Number 3, p.481-4, (1983) AbstractWebsite

Below 30 K, oxidized Desulfovibrio gigas hydrogenase presents an intense electron paramagnetic resonance (EPR) signal centered at g = 2.02, typical of an iron-sulfur center. In addition a rhombic EPR signal, attributed to Ni(III) species, is also observed [LeGall, J., Ljungdahl, P., Moura, I., Peck, H.D., Jr, Xavier, A.V., Moura, J.J.G., Teixeira, M., Huynh, B.H., and DerVartanian, D.V. (1982) Biochem. Biophys. Res. Commun. 106, 610-616; and Cammack, R., Patil, D., Aguirre, R., and Hatchikian, E.C., (1982) FEBS Lett. 142, 289-292]. At higher temperatures (77 K) the iron-sulfur EPR signal is broader and all the EPR features of the rhombic nickel signal can easily be observed. We have now obtained additional information concerning the redox properties of these EPR active centers, using an EPR redox titration method in the presence of dye mediators at pH = 8.5. The mid-point potential was determined to be -70 mV for the Fe,S cluster and -220 mV for the Ni center. Intermediate oxidation states were obtained upon partial reduction with either dithionite or hydrogen. Although upon dithionite reduction the centers are reduced in the order of decreasing mid-point reduction potentials, under a hydrogen atmosphere the nickel center reduces preferentially. This suggests a catalytic involvement of the nickel redox center in the binding of hydrogen. Preliminary Mossbauer studies on Desulfovibrio gigas hydrogenase reveal the presence of a paramagnetic 3 Fe center and two 4 Fe centers. The 3 Fe center is responsible for the g = 2.02 EPR signal but the two 4 Fe centers have been so far undetectable by EPR.

ESR studies of cytochrome c3 from Desulfovibrio desulfuricans strain Norway 4: Midpoint potentials of the four haems, and interactions with ferredoxin and colloidal sulphur, Cammack, R., Fauque G., Moura J. J. G., and Legall J. , Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, Volume 784, Number 1, p.68-74, (1984) AbstractWebsite
Nickel - a redox catalytic site in hydrogenase, Moura, J. J. G., Teixeira M., Moura I., Xavier A. V., and Legall J. , Journal of Molecular Catalysis, Volume 23, Number 2–3, p.303-314, (1984) AbstractWebsite
Nuclear-magnetic-resonance studies of Desulfuromonas acetoxidans cytochrome c551.5 (c7), Moura, José J. G., Moore Geoffrey R., Williams Robert J. P., Probst Irmelin, Legall Jean, and Xavier António V. , European Journal of Biochemistry, Volume 144, Number 3, p.433-440, (1984) AbstractWebsite

1H nuclear magnetic resonance (NMR) spectroscopy has been used to examine cytochrome c551.5 (c7) from the sulfur reducer, Desulfuromonas acetoxidans. This protein contains three hemes. Two stable oxidation states (the fully oxidized and the fully reduced) as well as intermediate oxidation states were studied. The axial ligands of the iron were found to be neutral histidines. The redox properties of cytochrome c7 were examined and good quantitative agreement found between the NMR results and previously reported redox potential measurements. The properties of cytochrome c7 are discussed together with those of the homologous tetraheme cytochromes c3 isolate from sulfate-reducing bacteria.