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Louro, RO, Catarino T, Salgueiro CA, Legall J, Xavier AV.  1996.  Redox-Bohr effect in the tetrahaem cytochrome c3 from Desulfovibrio vulgaris: a model for energy transduction mechanisms. Journal of Biological Inorganic Chemistry. 1(1):34-38. AbstractWebsite

Using potentiometric titrations, two protons were found to participate in the redox-Bohr effect observed for cytochrome c3 from Desulfovibrio vulgaris (Hildenborough). Within the framework of the thermodynamic model previously presented, this finding supports the occurrence of a concerted proton-assisted 2e– step, ideally suited for the coupling role of cytochrome c3 to hydrogenase. Furthermore, at physiological pH, it is shown that when sulfate-reducing bacteria use H2 as energy source, cytochrome c3 can be used as a charge separation device, achieving energy transduction by energising protons which can be left in the acidic periplasmic side and transferring deenergised electrons to sulfate respiration. This mechanism for energy transduction, using a full thermodynamic data set, is compared to that put forward to explain the proton-pumping function of cytochrome c oxidase.

Louro, RO, Pessanha M, Reid GA, Chapman SK, Turner DL, Salgueiro CA.  2002.  Determination of the orientation of the axial ligands and of the magnetic properties of the haems in the tetrahaem ferricytochrome from Shewanella frigidimarina. FEBS Letters. 531(3):520-524. AbstractWebsite

The unambiguous assignment of the nuclear magnetic resonance (NMR) signals of the α-substituents of the haems in the tetrahaem cytochrome isolated from Shewanella frigidimarina NCIMB400, was made using a combination of homonuclear and heteronuclear experiments. The paramagnetic 13C shifts of the nuclei directly bound to the porphyrin of each haem group were analysed in the framework of a model for the haem electronic structure. The analysis yields g-tensors for each haem, which allowed the assignment of some electron paramagnetic resonance (EPR) signals to specific haems, and the orientation of the magnetic axes relative to each haem to be established. The orientation of the axial ligands of the haems was determined semi-empirically from the NMR data, and the structural results were compared with those of the homologous tetrahaem cytochrome from Shewanella oneidensis MR-1 showing significant similarities between the two proteins.

Louro, RO, Catarino T, Salgueiro CA, Legall J, Turner DL, Xavier AV.  1998.  Molecular Basis for Energy Transduction: Mechanisms of Cooperativity in Multihaem Cytochromes. Biological Electron Transfer Chains: Genetics, Composition and Mode of Operation NATO ASI Series Volume 512. (Canters, G.W., Vijgenboom, E., Eds.).:209-223.: Springer Netherlands Abstract

Energy transduction through electron/proton cooperativity is at the heart of the metabolism of every living organism Nonetheless, the search for the structural bases sustaining these phenomena has been hindered by the fact that they are usually associated with complex transmembrane proteins of high molecular weight.

Louro, RO, Salgueiro CA.  2006.  Cytochromes of Shewanella respiratory pathways. Metal Ions in Biology and Medicine - volume 9. (Alpoim, M.C., Morais, P.V., Santos, MA, Cristovão, AJ, Centeno, JA, Collery, P, Eds.).:236-241., Paris: John Libbey Eurotext Abstract

No abstract included.