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Metal binding to the tetrathiolate motif of desulforedoxin and related polypeptides, Kennedy, M., Yu L., Lima M. J., Ascenso C. S., Czaja C., Moura I., Moura J. J. G., and Rusnak F. , Journal of Biological Inorganic Chemistry, Dec, Volume 3, Number 6, p.643-649, (1998) AbstractWebsite

Desulforedoxin and the N-terminus of desulfoferrodoxin share a 36 amino acid domain containing a (Cys-S)(4) metal binding site. Recombinant forms of desulforedoxin, an N-terminal fragment of desulfoferrodoxin, and two desulforedoxin mutant proteins were reconstituted with Fe3+ Cd2+, and Zn2+ and relative metal ion affinities assessed by proton titrations. Protons compete with metal for protein ligands, a process that can be followed by monitoring the optical spectrum of the metal-protein complex as a function of pH. For all polypeptides, Fe3+ bound with the highest affinity, whereas the affinity of Zn2+ was greater than Cd2+ in desulforedoxin and the N-terminal fragment of desulfoferrodoxin, but this order was reversed in desulforedoxin mutant proteins. Metal binding in both mutants was significantly impaired. Furthermore, the Fe3+ complex of both mutants underwent a time-dependent bleaching process which coincided with increased reactivity of cysteine residues to Ellman's reagent and concomitant metal dissociation. It is hypothesized that this results from an autoredox reaction in which Fe3+ is reduced to Fe2+ with attendant oxidation of ligand thiols.

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
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Cobalt-, zinc- and iron-bound forms of adenylate kinase (AK) from the sulfate-reducing bacterium Desulfovibrio gigas: purification, crystallization and preliminary X-ray diffraction analysis, Kladova, A. V., Gavel O. Y., Mukhopaadhyay A., Boer D. R., Teixeira S., Shnyrov V. L., Moura I., Moura J. J., Romao M. J., Trincao J., and Bursakov S. A. , Acta Crystallogr Sect F Struct Biol Cryst Commun, Sep 1, Volume 65, Number Pt 9, p.926-9, (2009) AbstractWebsite

Adenylate kinase (AK; ATP:AMP phosphotransferase; EC 2.7.4.3) is involved in the reversible transfer of the terminal phosphate group from ATP to AMP. AKs contribute to the maintenance of a constant level of cellular adenine nucleotides, which is necessary for the energetic metabolism of the cell. Three metal ions, cobalt, zinc and iron(II), have been reported to be present in AKs from some Gram-negative bacteria. Native zinc-containing AK from Desulfovibrio gigas was purified to homogeneity and crystallized. The crystals diffracted to beyond 1.8 A resolution. Furthermore, cobalt- and iron-containing crystal forms of recombinant AK were also obtained and diffracted to 2.0 and 3.0 A resolution, respectively. Zn(2+)-AK and Fe(2+)-AK crystallized in space group I222 with similar unit-cell parameters, whereas Co(2+)-AK crystallized in space group C2; a monomer was present in the asymmetric unit for both the Zn(2+)-AK and Fe(2+)-AK forms and a dimer was present for the Co(2+)-AK form. The structures of the three metal-bound forms of AK will provide new insights into the role and selectivity of the metal in these enzymes.

Electronic and magnetic properties of nickel-substituted rubredoxin: a variable-temperature magnetic circular dichroism study, Kowal, Andrzej T., Zambrano Isabel C., Moura Isabel, Moura Jose J. G., Legall Jean, and Johnson Michael K. , Inorganic Chemistry, 1988/04/01, Volume 27, Number 7, p.1162-1166, (1988) AbstractWebsite
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Immunocytochemical localization of APS reductase and bisulfite reductase in three <i>Desulfovibrio</i> species, Kremer, D. R., Veenhuis M., Fauque G., Peck H. D., Legall J., Lampreia J., Moura J. J. G., and Hansen T. A. , Archives of Microbiology, Volume 150, Number 3, p.296-301, (1988) AbstractWebsite

The localization of APS reductase and bisulfite reductase in Desulfovibrio gigas, D. vulgaris Hildenborough and D. thermophilus was studied by immunoelectron microscopy. Polyclonal antibodies were raised against the purified enzymes from each strain. Cells fixed with formaldehyde/glutaraldehyde were embedded and ultrathin sections were incubated with antibodies and subsequently labeled with protein A-gold. The bisulfite reductase in all three strains and APS reductase in d. gigas and D. vulgaris were found in the cytoplasm. The labeling of d. thermophilus with APS reductase antibodies resulted in a distribution of gold particles over the cytoplasmic membrane region. The localization of the two enzymes is discussed with respect to the mechanism and energetics of dissimilatory sulfate reduction.

Modeling protein complexes with BiGGER, Krippahl, L., Moura J. J., and Palma P. N. , Proteins, Jul 1, Volume 52, Number 1, p.19-23, (2003) AbstractWebsite

This article describes the method and results of our participation in the Critical Assessment of PRediction of Interactions (CAPRI) experiment, using the protein docking program BiGGER (Bimolecular complex Generation with Global Evaluation and Ranking) (Palma et al., Proteins 2000;39:372-384). Of five target complexes (CAPRI targets 2, 4, 5, 6, and 7), only one was successfully predicted (target 6), but BiGGER generated reasonable models for targets 4, 5, and 7, which could have been identified if additional biochemical information had been available.

Modelling the electron-transfer complex between aldehyde oxidoreductase and flavodoxin, Krippahl, Ludwig, Palma Nuno P., Moura Isabel, and Moura Jose J. G. , European Journal of Inorganic Chemistry, Oct 2, Number 19, p.3835-3840, (2006) AbstractWebsite

Three-dimensional protein structures of the xanthine oxidase family show different solutions for the problem of transferring electrons between the flavin adenine dinucleotide (FAD) group and the molybdenum cofactor. In xanthine oxidase all the cofactors he within domains of the same protein chain, whereas in CO dehydrogenase the Fe-S centres, FAD and Mo cofactors are enclosed in separate chains and the enzyme exists as a stable complex of all three. In aldehyde oxidore-ductase, only Fe-S and Mo co-factors are present in a single protein chain. Flavodoxin is docked to aldehyde oxidoreductase to mimic the flavin component on the intramolecular electron transfer chain of aanthine oxidase and CO dehydrogenase and, remarkably, the main features of the electron-transfer pathway are observed.

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.