Formation of a Stable Cyano-Bridged Dinuclear Iron Cluster Following Oxidation of the Superoxide Reductases from Treponema pallidum and Desulfovibrio vulgaris
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- 作者：Franç ; oise Auchè ; re ; Patrí ; cia Raleiras ; Linda Benson ; Sergei Yu. Venyaminov ; Pedro Tavares ; José ; J. G. Moura ; Isabel Moura ; and Frank Rusnak
- 刊名：Inorganic Chemistry
- 出版年：2003
- 出版时间：February 24, 2003
- 年：2003
- 卷：42
- 期：4
- 页码：938 - 940
- 全文大小：65K
- 年卷期：v.42,no.4(February 24, 2003)
- ISSN：1520-510X
文摘
Superoxide reductases catalyze the monovalent reduction ofsuperoxide anion to hydrogen peroxide. Spectroscopic evidencefor the formation of a dinuclear cyano-bridged adduct after K3Fe(CN)6 oxidation of the superoxide reductases neelaredoxin fromTreponema pallidum and desulfoferrodoxin from Desulfovibriovulgaris was reported. Oxidation with K3Fe(CN)6 reveals a bandin the near-IR with 
max at 1020 nm, coupled with an increase ofthe iron content by almost 2-fold. Fourier transform infraredspectroscopy provided additional evidence with CN-stretchingvibrations at 2095, 2025-2030, and 2047 cm-1, assigned to aferrocyanide adduct of the enzyme. Interestingly, the low-temperature electronic paramagnetic resonance (EPR) spectra ofoxidized TpNlr reveal at least three different species indicatingstructural heterogeneity in the coordination environment of theactive site Fe ion. Given the likely 6-coordinate geometry of theactive site Fe3+ ion in the ferrocyanide adduct, we propose thatthe rhombic EPR species can serve as a model of a hexacoordinate form of the active site.
max at 1020 nm, coupled with an increase ofthe iron content by almost 2-fold. Fourier transform infraredspectroscopy provided additional evidence with CN-stretchingvibrations at 2095, 2025-2030, and 2047 cm-1, assigned to aferrocyanide adduct of the enzyme. Interestingly, the low-temperature electronic paramagnetic resonance (EPR) spectra ofoxidized TpNlr reveal at least three different species indicatingstructural heterogeneity in the coordination environment of theactive site Fe ion. Given the likely 6-coordinate geometry of theactive site Fe3+ ion in the ferrocyanide adduct, we propose thatthe rhombic EPR species can serve as a model of a hexacoordinate form of the active site.