Science 2007 Apr;316(5823):449-53
Institut de Biologie Structurale (IBS) Jean-Pierre Ebel, Commissariat à l'Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier, 41 rue Jules Horowitz, F-38027 Grenoble, France.
Iron-peroxide intermediates are central in the reaction cycle of many iron-containing biomolecules. We trapped iron(III)-(hydro)peroxo species in crystals of superoxide reductase (SOR), a nonheme mononuclear iron enzyme that scavenges superoxide radicals. X-ray diffraction data at 1.95 angstrom resolution and Raman spectra recorded in crystallo revealed iron-(hydro)peroxo intermediates with the (hydro)peroxo group bound end-on. The dynamic SOR active site promotes the formation of transient hydrogen bond networks, which presumably assist the cleavage of the iron-oxygen bond in order to release the reaction product, hydrogen peroxide.