Cooperative use of cytochrome cd1 nitrite reductase and its redox partner cytochrome c552 to Improve the selectivity of nitrite biosensing,
A.S., Serra, S. Jorge, C. Silveira, J.J.G. Moura, E. Jubete, E. Ochoteco, and G. Almeida M.
, Anal Chim Acta, Volume 693, p.41-46, (2011)
A copper protein and a cytochrome bind at the same site on bacterial cytochrome c peroxidase,
Pauleta, S. R., Cooper A., Nutley M., Errington N., Harding S., Guerlesquin F., Goodhew C. F., Moura I., Moura J. J., and Pettigrew G. W.
, Biochemistry, Nov 23, Volume 43, Number 46, p.14566-76, (2004)
AbstractPseudoazurin binds at a single site on cytochrome c peroxidase from Paracoccus pantotrophus with a K(d) of 16.4 microM at 25 degrees C, pH 6.0, in an endothermic reaction that is driven by a large entropy change. Sedimentation velocity experiments confirmed the presence of a single site, although results at higher pseudoazurin concentrations are complicated by the dimerization of the protein. Microcalorimetry, ultracentrifugation, and (1)H NMR spectroscopy studies in which cytochrome c550, pseudoazurin, and cytochrome c peroxidase were all present could be modeled using a competitive binding algorithm. Molecular docking simulation of the binding of pseudoazurin to the peroxidase in combination with the chemical shift perturbation pattern for pseudoazurin in the presence of the peroxidase revealed a group of solutions that were situated close to the electron-transferring heme with Cu-Fe distances of about 14 A. This is consistent with the results of (1)H NMR spectroscopy, which showed that pseudoazurin binds closely enough to the electron-transferring heme of the peroxidase to perturb its set of heme methyl resonances. We conclude that cytochrome c550 and pseudoazurin bind at the same site on the cytochrome c peroxidase and that the pair of electrons required to restore the enzyme to its active state after turnover are delivered one-by-one to the electron-transferring heme.
Crystal structure of the xanthine oxidase-related aldehyde oxido-reductase from D. gigas,
Romao, M. J., Archer M., Moura I., Moura J. J., Legall J., Engh R., Schneider M., Hof P., and Huber R.
, Science, Nov 17, Volume 270, Number 5239, p.1170-6, (1995)
AbstractThe crystal structure of the aldehyde oxido-reductase (Mop) from the sulfate reducing anaerobic Gram-negative bacterium Desulfovibrio gigas has been determined at 2.25 A resolution by multiple isomorphous replacement and refined. The protein, a homodimer of 907 amino acid residues subunits, is a member of the xanthine oxidase family. The protein contains a molybdopterin cofactor (Mo-co) and two different [2Fe-2S] centers. It is folded into four domains of which the first two bind the iron sulfur centers and the last two are involved in Mo-co binding. Mo-co is a molybdenum molybdopterin cytosine dinucleotide. Molybdopterin forms a tricyclic system with the pterin bicycle annealed to a pyran ring. The molybdopterin dinucleotide is deeply buried in the protein. The cis-dithiolene group of the pyran ring binds the molybdenum, which is coordinated by three more (oxygen) ligands.