A needle in a haystack: the active site of the membrane-bound complex cytochrome c nitrite reductase.

Abstract

Cytochrome c nitrite reductase is a multicenter enzyme that uses a five-coordinated heme to perform the six-electron reduction of nitrite to ammonium. In the sulfate reducing bacterium Desulfovibrio desulfuricans ATCC 27774, the enzyme is purified as a NrfA2NrfH complex that houses 14 hemes. The number of closely-spaced hemes in this enzyme and the magnetic interactions between them make it very difficult to study the active site by using traditional spectroscopic approaches such as EPR or UV-Vis. Here, we use both catalytic and non-catalytic protein film voltammetry to simply and unambiguously determine the reduction potential of the catalytic heme over a wide range of pH and we demonstrate that proton transfer is coupled to electron transfer at the active site.

Cite this paper

@article{Almeida2007ANI, title={A needle in a haystack: the active site of the membrane-bound complex cytochrome c nitrite reductase.}, author={M. Gabriela Almeida and C{\'e}lia M. Silveira and Bruno Guigliarelli and P. Bertrand and Jos{\'e} J. G. Moura and Isabel Moura and Christophe L{\'e}ger}, journal={FEBS letters}, year={2007}, volume={581 2}, pages={284-8} }