Some sulfate-reducing and microaerophilic bacteria rely on the enzyme superoxide reductase (SOR) to eliminate the toxic superoxide anion radical (O2·-). SOR catalyses the one-electron reduction of O2·- to hydrogen peroxide at a nonheme ferrous iron center. The structures of Desulfoarculus baarsii SOR (mutant E47A) alone and in complex with ferrocyanide were solved to 1.15 and 1.7 Å resolution, respectively. The latter structure, the first ever reported of a complex between ferrocyanide and a protein, reveals that this organo-metallic compound entirely plugs the SOR active site, coordinating the active iron through a bent cyano bridge. The subtle structural differences between the mixed-valence and the fully reduced SOR-ferrocyanide adducts were investigated by taking advantage of the photoelectrons induced by X-rays. The results reveal that photo-reduction from Fe(III) to Fe(II) of the iron center, a very rapid process under a powerful synchrotron beam, induces an expansion of the SOR active site.
CITATION STYLE
Adam, V., Royant, A., Nivière, V., Molina-Heredia, F. P., & Bourgeois, D. (2004). Structure of superoxide reductase bound to ferrocyanide and active site expansion upon X-ray-induced photo-reduction. Structure, 12(9), 1729–1740. https://doi.org/10.1016/j.str.2004.07.013
Mendeley helps you to discover research relevant for your work.