Evidence of His61 Imidazolate Bridge Rupture in Reduced Crystalline Cu,Zn Superoxide Dismutase

Ascone, I.; Castañer, R.; Tarricone, C.; Bolognesi, Martino; Stroppolo, Maria Elena; Desideri, Alessandro

doi:10.1006/bbrc.1997.7777

Cited by 28 publications

(22 citation statements)

References 18 publications

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“…34 The main difference between the XANES spectra of an oxidized and a reduced copper ion is a shoulder in energy below that of metal edge, around 8983 eV, observed for the reduced copper(I) but not for the oxidized metal. 36 This pre-edge absorption is attributed to a 1s → 4s electronic transition. XANES spectrum of copper(II) ion shows the first intense transition at 8986 eV, assigned to a 1s to 4s transition or 1s to 4p transition.…”

Section: Resultsmentioning

confidence: 97%

“…XANES spectrum of copper(II) ion shows the first intense transition at 8986 eV, assigned to a 1s to 4s transition or 1s to 4p transition. 36 Although it is possible to determine the presence of both copper(I) and copper(II) complexes in the immobilized [Cu(pyalen)] 2+ ( Figure 5), a predominance of the copper(I) complex can be observed. While the [Cu(apzpn)]/ LPN sample resembles that of the free complex ( Figure 1S), with more contribution of the copper(II) to the spectrum (pre-edge at 8983 eV), the [Cu(apzpn)]/SWy-2 shows a pronounced band at 8985 eV attributed to the copper(I) complex.…”

Section: Resultsmentioning

confidence: 99%

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Spectroscopic characterization of schiff base-copper complexes immobilized in smectite clays

Dias¹,

Kinouti²,

Constantino³

et al. 2010

Quím. Nova

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Recebido em 5/7/10; aceito em 17/9/10; publicado na web em 25/10/10 Herein, the immobilization of some Schiff base-copper(II) complexes in smectite clays is described as a strategy for the heterogenization of homogeneous catalysts. The obtained materials were characterized by spectroscopic techniques, mostly UV/Vis, EPR, XANES and luminescence spectroscopy. SWy-2 and synthetic Laponite clays were used for the immobilization of two different complexes that have previously shown catalytic activity in the dismutation of superoxide radicals, and disproportionation of hydrogen peroxide. The obtained results indicated the occurrence of an intriguing intramolecular redox process involving copper and the imine ligand at the surface of the clays. These studies are supported by computational calculations.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Spectroscopic characterization of schiff base-copper complexes immobilized in smectite clays

Dias¹,

Kinouti²,

Constantino³

et al. 2010

Quím. Nova

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“…Thorough analyses at the molecular level of structural changes that accompany copper reduction have been undertaken to detail the active site properties at the origin of the efficient superoxide dismutation and of the protonation events associated with its reduction into hydrogen peroxide (3,5,10,(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34). A main result concerns the rupture of the interaction between reduced Cu(I) and the His-63 bridging ligand, as deduced by NMR (10,(23)(24)(25), extended X-ray absorption fluorescence spectroscopy (26,27), and Raman spectroscopy (28 -30) for Cu,Zn-SOD in solution. Three-dimensional crystallographic structures of reduced Cu,Zn-SOD presented heterogeneity of the active center (16,(31)(32)(33), but a recent high resolution structure provided convincing evidence for three coordinated Cu(I) (34), in agreement with other spectroscopic data.…”

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confidence: 99%

Long Distance Charge Redistribution Upon Cu,Zn-Superoxide Dismutase Reduction

Dupeyrat

Vidaud

Lorphelin

et al. 2004

Journal of Biological Chemistry

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Cu,Zn-superoxide dismutase (Cu,Zn-SOD) is a ubiquitous enzyme with an essential role in antioxidant defense. To better understand structural factors at the origin of the highly efficient superoxide dismutation mechanism, we analyzed the consequence of copper reduction on the electronic properties of the backbone and individual amino acids by using electrochemistry coupled to Fourier transform infrared spectroscopy. Comparison of data recorded with bovine erythrocyte and recombinant chloroplastic Cu,Zn-SOD from Lycopersicon esculentum, expressed as a functional tetramer in Escherichia coli and 14 N-or fully 15 N-labeled, demonstrated that the infrared changes were dominated by reorganizations of peptide bonds and histidine copper ligands. Two main infrared modes of histidine side chain, markers of metal coordination, were identified by using Cu-and Zn-methylimidazole models: the (C 4 C 5 ) at 1605-1594 cm ؊1 or Ϸ1586 cm ؊1 for N or N coordination, and the (C 5 N ) at Ϸ1113-1088 cm ؊1 . These modes, also identified in Cu,Zn-SOD by using 15 N labeling, showed that the electronic properties of the histidine N ligands of copper are mostly affected upon copper reduction. A striking conclusion of this work is that peptide groups from loops and ␤-sheet largely participate in charge redistribution upon copper reduction, and in contrast, electronic properties of polar and charged amino acids of the superoxide access channel remain unaffected. This is notably shown for the strictly conserved Arg-143 by site-directed mutagenesis on chloroplastic Cu,Zn-SOD. Charge compensation by the peptide backbone and preserved electronic properties of the superoxide access channel and docking site upon copper reduction may be the determinant factors for the high reaction kinetics of superoxide with both reduced and oxidized Cu,Zn-SOD.

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“…The Cu-His60-Zn imidazolate bridge that is intact in both monomers is consistent with Cu 2+ . In the reduced form, the imidazolate bridge is ruptured and the catalytic metal is three coordinated [25], whereas, if Cu is oxidized, it is coordinated to four His residues and is also connected to Zn through a bridging His residue [26]. In the Taenia enzyme, His60 makes a bridge between Cu 2+ and Zn 2+ ions, spanning 6.12 and 6.33 Å for monomers A and B, respectively.…”

Section: Crystal Structure Overviewmentioning

confidence: 99%

Crystal structure of Cu / Zn superoxide dismutase from Taenia solium reveals metal‐mediated self‐assembly

et al. 2011

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Taenia solium is the cestode responsible for porcine and human cysticercosis. The ability of this parasite to establish itself in the host is related to its evasion of the immune response and its antioxidant defence system. The latter includes enzymes such as cytosolic Cu ⁄ Zn superoxide dismutase. In this article, we describe the crystal structure of a recombinant T. solium Cu ⁄ Zn superoxide dismutase, representing the first structure of a protein from this organism. This enzyme shows a different charge distribution at the entrance of the active channel when compared with human Cu ⁄ Zn superoxide dismutase, giving it interesting properties that may allow the design of specific inhibitors against this cestode. The overall topology is similar to other superoxide dismutase structures; however, there are several His and Glu residues on the surface of the protein that coordinate metal ions both intra-and intermolecularly. Interestingly, one of these ions, located on the b2 strand, establishes a metal-mediated intermolecular b-b interaction, including a symmetry-related molecule. The factors responsible for the abnormal proteinprotein interactions that lead to oligomerization are still unknown; however, high metal levels have been implicated in these phenomena, but exactly how they are involved remains unclear. The present results suggest that this structure could be useful as a model to explain an alternative mechanism of protein aggregation commonly observed in insoluble fibrillar deposits. DatabaseThe atomic coordinates and structure factors have been deposited in the Protein Data Bank under the accession number 3MND.

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Evidence of His61 Imidazolate Bridge Rupture in Reduced Crystalline Cu,Zn Superoxide Dismutase

Cited by 28 publications

References 18 publications

Spectroscopic characterization of schiff base-copper complexes immobilized in smectite clays

Spectroscopic characterization of schiff base-copper complexes immobilized in smectite clays

Long Distance Charge Redistribution Upon Cu,Zn-Superoxide Dismutase Reduction

Crystal structure of Cu / Zn superoxide dismutase from Taenia solium reveals metal‐mediated self‐assembly

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