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The Role Of Nickel And Iron Sulfur Centers In The Bioproduction Of Hydrogen, Moura, J. J. G., Teixeira M., and Moura I. , Pure and Applied Chemistry, May, Volume 61, Number 5, p.915-921, (1989) AbstractWebsite
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NMR studies of a dihaem cytochrome from Pseudomonas perfectomarinus (ATCC 14405), Moura, I., Liu M. C., Legall J., Peck, H. D. Jr., Payne W. J., Xavier A. V., and Moura J. J. , Eur J Biochem, Jun 1, Volume 141, Number 2, p.297-303, (1984) AbstractWebsite

Pseudomonas perfectomarinus (ATCC 14405) dihaem cytochrome c552 was studied by 300-MHz proton magnetic resonance. Some of the haem resonances were assigned in the fully reduced and fully oxidized states. No evidence was found for methionine haem axial coordination. The oxidation-reduction equilibrium was studied in detail. Due to the large difference in mid-point redox potential between the two haems (+174 mV, for haem II and -180 mV for haem I) an intermediate oxidation state could be obtained containing reduced haem I and oxidized haem II. In this way the total paramagnetic shift at different oxidation levels could be decomposed in the intrinsic and extrinsic contributions. It was found that the two haems interact. The rate of electron exchange is slow on the NMR time scale. The redox equilibria are discussed for four possible redox species in solution.

A molybdenum-containing (2Fe, 2S) protein from desulphovibrio gigas, a sulphate reducer, Moura, J. J. G., Xavier A. V., Bruschi M., Legall J., and Cabral J. M. P. , Journal of the Less Common Metals, Volume 54, Number 2, p.555-562, (1977) AbstractWebsite
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Spectroscopic studies of cobalt and nickel substituted rubredoxin and desulforedoxin, Moura, I., Teixeira M., Legall J., and Moura J. J. , J Inorg Biochem, Nov, Volume 44, Number 2, p.127-39, (1991) AbstractWebsite

The single iron site of rubredoxin was replaced by nickel and cobalt. The near-infrared/visible/UV spectra of these metal derivatives show ligand-field transitions and charge-transfer bands which closely resemble those of simple tetrathiolate complexes, indicating a tetrahedral arrangement of the sulfur cysteinyl ligands around the metal core. The 1H NMR spectra of the nickel and cobalt derivatives reveal extremely low-field contact shifted resonances of one proton intensity assigned to beta-CH2 and alpha-CH cysteinyl protons. Other well resolved resonances shifted out of the main protein spectral envelope are also observed and probably arise from contact plus pseudocontact shift mechanisms. Rubredoxins from different sulfate reducers were metal substituted and assignments of aliphatic protons are tentatively proposed, taking advantage of the amino acid sequence homologies. The present data is promising in terms of structural analysis of the coordination sphere of the metal core. It was also shown that replacement of the iron atom of desulforedoxin, a close analogue of rubredoxin, by cobalt and nickel was possible.

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.

Structural control of the redox potentials and of the physiological activity by oligomerization of ferredoxin, Moura, J. J., Xavier A. V., Hatchikian E. C., and Legall J. , FEBS Lett, May 1, Volume 89, Number 1, p.177-9, (1978) AbstractWebsite
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A bird’s-eye view of denitrification in relation to the nitrogen cycle, Moura, I., Maia L. B., Pauleta S. R., and Moura J. J. G. , Metalloenzymes in Denitrification: Applications and Environmental Impacts, RSC Metallobiology Series No. 9 (ISBN: 978-1-78262-376-2)., Cambridge, p.1-10, (2017) n_cycle-rsc_book-denitrification-chap_1.pdf
Crystal structure of the zinc-, cobalt-, and iron-containing adenylate kinase from Desulfovibrio gigas: a novel metal-containing adenylate kinase from Gram-negative bacteria, Mukhopadhyay, A., Kladova A. V., Bursakov S. A., Gavel O. Y., Calvete J. J., Shnyrov V. L., Moura I., Moura J. J., Romao M. J., and Trincao J. , J Biol Inorg Chem, Jan, Volume 16, Number 1, p.51-61, (2011) AbstractWebsite

Adenylate kinases (AK) from Gram-negative bacteria are generally devoid of metal ions in their LID domain. However, three metal ions, zinc, cobalt, and iron, have been found in AK from Gram-negative bacteria. Crystal structures of substrate-free AK from Desulfovibrio gigas with three different metal ions (Zn(2+), Zn-AK; Co(2+), Co-AK; and Fe(2+), Fe-AK) bound in its LID domain have been determined by X-ray crystallography to resolutions 1.8, 2.0, and 3.0 A, respectively. The zinc and iron forms of the enzyme were crystallized in space group I222, whereas the cobalt-form crystals were C2. The presence of the metals was confirmed by calculation of anomalous difference maps and by X-ray fluorescence scans. The work presented here is the first report of a structure of a metal-containing AK from a Gram-negative bacterium. The native enzyme was crystallized, and only zinc was detected in the LID domain. Co-AK and Fe-AK were obtained by overexpressing the protein in Escherichia coli. Zn-AK and Fe-AK crystallized as monomers in the asymmetric unit, whereas Co-AK crystallized as a dimer. Nevertheless, all three crystal structures are very similar to each other, with the same LID domain topology, the only change being the presence of the different metal atoms. In the absence of any substrate, the LID domain of all holoforms of AK was present in a fully open conformational state. Normal mode analysis was performed to predict fluctuations of the LID domain along the catalytic pathway.

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