Redox chemistry of superoxide dismutase. Cyclic voltammetry of wild-type enzymes and mutants on functionally relevant residues

Azab, Hassan A.; Banci, Lucia; Borsari, Marco; Luchinat, Claudio; Sola, Marcó; Viezzoli, Maria Silvia

doi:10.1021/ic00048a037

Cited by 80 publications

(58 citation statements)

References 2 publications

(3 reference statements)

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“…A similar decrease in the reduction potential was observed in the Aspl24--.Asn mutant [40]. In [Cys63]SOD the affinity for anions is only slightly affected suggesting that the electrostatic attraction of the 0; substrate to the active site is near normal.…”

Section: Discussionsupporting

confidence: 65%

See 1 more Smart Citation

Mutation of the Metal‐Bridging Proton‐Donor His63 Residue in Human Cu, Zn Superoxide Dismutase

Banci¹,

Bertini²,

Borsari³

et al. 1995

European Journal of Biochemistry

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The bridging His63 residue in human Cu, Zn superoxide dismutase, which binds both metals, has been replaced by a Cys residue. The mutant protein has been purified from Escherichia coti and appears to be a normal dimer. Spectroscopic techniques (electronic spectroscopies, EPR, nuclear magnetic relaxation dispersion) show that Cys63 binds the zinc ion, but not the copper ion, and that the latter is probably five co-ordinated with three histidine ligands and two water molecules. The reduction potential of the copper ion in the Cuz'/Cu' pair decreases from 0.41 V to 0.27 V at neutral pH but still remains intermediate between those of the O,/O; and O;/H,O, pairs so that copper can both oxidize and reduce the 0; substrate, a requirement for dismutase activity. The enzyme binds the substrate-analogue azide (N;), which displaces one water molecule, with near normal affinity, whereas the enzyme activity with the 0; substrate is reduced to less than 1 % of wild-type levels at pH 7.8. The properties of the mutant enzyme are discussed in relation to the superoxide-copper electron transfer process and to the catalytic mechanism.

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Section: Discussionsupporting

confidence: 65%

“…The use of gold electrodes modified by promotors to obtain direct electrochemistry of superoxide dismutase has been already discussed and successfully applied to several mutants [40]. The differential pulse polarograms of the present protein show only one reduction peak.…”

Section: Spectroscopic Characterization the Cu Zn Derivative Cu Znmentioning

confidence: 98%

Mutation of the Metal‐Bridging Proton‐Donor His63 Residue in Human Cu, Zn Superoxide Dismutase

Banci¹,

Bertini²,

Borsari³

et al. 1995

European Journal of Biochemistry

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“…It is interesting to note that the Cu 2+/1+ redox couples of the present copper conjugates (+0.30 to +0.08 V) are very similar to the redox potentials of the native SOD enzyme [42] which may be of relevance to their anti-inflammatory activities. Present studies thus clearly establish that copper conjugation in case of COX-2 inhibitors like 2 significantly enhances its SOD activity thereby offering the possibility of lowering its therapeutic dose which may be beneficial in its clinical use.…”

mentioning

confidence: 59%

Structural characterization and SOD activity of copper–oxaprozinate

Dutta

Padhyé

McKee

2004

Inorganic Chemistry Communications

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“…A large range of midpoint potentials (120 -525 mV) has been reported for Cu,Zn-SOD (51,(52)(53)(54)(55)(56)(57)(58). In particular, midpoint potentials ranging from 260 to 525 mV/NHE have been obtained for Cu,Zn-SOD using cyclic voltammetry at high sweep rates, depending on the electrode surface modifier, 1,2-bis(4-pyridyl)-ethene (53-54), cysteine-or 3-mercaptopropionic acid (55,56), bis(4-pyridyl)disulfide (4,4Ј-PySSPy), or His or Arg solutions (57).…”

Section: Electrochemistry Of Cuzn-sodmentioning

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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Redox chemistry of superoxide dismutase. Cyclic voltammetry of wild-type enzymes and mutants on functionally relevant residues

Cited by 80 publications

References 2 publications

Mutation of the Metal‐Bridging Proton‐Donor His63 Residue in Human Cu, Zn Superoxide Dismutase

Mutation of the Metal‐Bridging Proton‐Donor His63 Residue in Human Cu, Zn Superoxide Dismutase

Structural characterization and SOD activity of copper–oxaprozinate

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

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