Characterization of the cobalt(II)-substituted superoxide dismutase-phosphate systems

Banci, Lucia; Bertini, Ivano; Luchinat, Claudio; Monnanni, Roberto; Scozzafava, Andrea

doi:10.1021/ic00248a030

Cited by 26 publications

(20 citation statements)

References 1 publication

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“…The highest energy band (537 nm) barely shifted. Similar changes were previously observed by Banci et al in the analogous derivatives of bovine CuZnSOD, and the changes were attributed to the influence of Cu(II) in the copper site on the environment of Co(II) in the zinc site through the formation of the imidazolate bridge between the two metal ions. After careful comparisons of the optical spectra of several cobalt(II) derivatives of CuZnSOD, those authors concluded that addition of a metal into the copper site of the E 2 Co 2 caused a shift of the three Co(II) d−d transitions only if the imidazolate bridge formed between the two metals.…”

Section: Resultssupporting

confidence: 86%

New Type 2 Copper−Cysteinate Proteins. Copper Site Histidine-to-Cysteine Mutants of Yeast Copper−Zinc Superoxide Dismutase

Roe

Bender

et al. 1996

Inorg. Chem.

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Preparation and characterization of two new site-directed mutant copper-zinc superoxide dismutase proteins from Saccharomyces cerevisiae, i.e., His46Cys (H46C) and His120Cys (H120C), in which individual histidyl ligands in the copper-binding site were replaced by cysteine, are reported here. These two mutant CuZnSOD proteins may be described as type 2 (or normal) rather than type 1 (or blue) copper-cysteinate proteins and are characterized by their yellow rather than blue color, resulting from intense copper-to-sulfur charge transfer bands around 400 nm, their type 2 EPR spectra, with large rather than small nuclear hyperfine interactions, and their characteristic type 2 d-d electronic absorption spectra. An interesting difference between these two copper site His-to-Cys mutations is that the imidazolate bridge between the two metal sites that is characteristic of the wild-type protein remains intact in the case of the H46C mutant but is not present in the case of the H120C mutant.

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Section: Resultssupporting

confidence: 86%

New Type 2 Copper−Cysteinate Proteins. Copper Site Histidine-to-Cysteine Mutants of Yeast Copper−Zinc Superoxide Dismutase

Roe

Bender

et al. 1996

Inorg. Chem.

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“…In conclusion, these profiles indicate that in the absence of phthalate there is a fast exchanging water molecule about 2.5 Å from the copper nucleus. This distance is the same as that found for copper-superoxide dismutase [33].…”

Section: Best-fit For Cupdo Without Phthalatesupporting

confidence: 81%

NMRD studies on phthalate dioxygenase: evidence for displacement of water on binding substrate

et al. 1996

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Water proton T 1-1 measurements at magnetic fields between 0.01 and 50 MHz [nuclear magnetic relaxation dispersion (NMRD) measurements] have been performed on solutions of phthalate dioxygenase (PDO) reconstituted at the catalytic iron site with copper(II) or manganese(II). The data show evidence of a weakly coordinated water molecule in CuPDO; in the presence of the substrate, phthalate, this water appears to become even less tightly bound, and an additional tightly coordinated water can be detected. In PDO reconstituted with manganese, one tightly coordinated water is detected in the presence and in the absence of phthalate. An attempt is made to reconcile these data with low-temperature near-IR magnetic circular dichroism and X-ray absorption data, which show that PDO reconstituted with iron or cobalt is six-coordinate in the absence of substrate and five-coordinate in the presence of substrate. Key words Metalloenzymes 7 Nuclear magnetic resonance 7 Aromatic compounds 7 biodegradation 7 hydration Abbreviations PDO Phthalate dioxygenase; NMRD Nuclear magnetic relaxation dispersion, apo-PDO phthalate dioxygenase with the mononuclear divalent metal removed, FePDO, ZnPDO, MnPDO, CuPDO, phthalate dioxygenase that has been reconstituted with the indicated metal

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“…Addition of azide to the wild-type protein affects the electronic spectra which show the appearance of a chargetransfer transition around 28 600 cm-' in the CD spectrum (Fig. 2B), due to the binding of N,-to the copper ion [37, 381. The changes observed by addition of increasing amounts of azide indicates that 1 equivalent of azide bind the copper ion, possibly displacing a copper-bound water molecule as occurs in the wild-type enzyme [39]. By fitting the absorbance at 27800 cm-' as a function of increasing amounts of azide, an affinity constant of 170 ?…”

Section: Spectroscopic Characterization the Cu Zn Derivative Cu Znmentioning

confidence: 97%

“…It follows that azide displaces a water molecule from coordination when it binds copper. In the adduct of wild-type superoxide dismutase with azide the NMRD profile is quite low, indicating that in the wild type the water molecule at 0.25 nm from copper is also displaced upon azide binding [39].…”

Section: Spectroscopic Characterization the Cu Zn Derivative Cu Znmentioning

confidence: 99%

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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Characterization of the cobalt(II)-substituted superoxide dismutase-phosphate systems

Cited by 26 publications

References 1 publication

New Type 2 Copper−Cysteinate Proteins. Copper Site Histidine-to-Cysteine Mutants of Yeast Copper−Zinc Superoxide Dismutase

New Type 2 Copper−Cysteinate Proteins. Copper Site Histidine-to-Cysteine Mutants of Yeast Copper−Zinc Superoxide Dismutase

NMRD studies on phthalate dioxygenase: evidence for displacement of water on binding substrate

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

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