Studies of the metal sites of copper proteins. V. A model compound for the copper site of superoxide dismutase

Morpurgo, Laura; Giovagnoli, Carlo; Rotilio, Giuseppe

doi:10.1016/0005-2795(73)90294-8

Cited by 38 publications

(10 citation statements)

References 14 publications

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“…Figure 5 (upper panel) shows the spectrum of N3"-reacted SOD in the frequency range 20 000-32 000 cm"1 at 10 and 300 K; the deconvolution of the 10 K spectrum in terms of Gaussian components is shown in the lower panel of Figure 5. The intense peak at *s26 700 cm™1 in the roomtemperature spectrum and attributed to a Cu-N3™ charge transfer transition (Morpurgo et al, 1973) clearly shows a composite structure in the 10 K spectrum. In fact, it also contains a band at %24 000 cm™1, which, in analogy with the native derivative, can be attributed to a LMCT transition involving the imidazole of His61.…”

Section: Resultsmentioning

confidence: 97%

“…Nf-Reacted Enzyme. The electronic spectrum of the azide derivative of Cu,Zn SOD has been investigated in two different sets of experiments, with samples having different concentrations because of the high extinction coefficient of the Cu-N3charge transfer band at about 26 700 cm-1 (Morpurgo et al, 1973). Figure 3 (upper panel) shows the optical absorption spectrum of an N3~-bound SOD derivative from 10 000 to 22 000 cm-1 at 10 and 300 K. Lowering the temperature produces a splitting of the broad band at 15 000 cm-1; this splitting, although it is not so pronounced as the one observed in the native enzyme, enables us to solve two bands centered at 14 418 and 16 300 cm-1, respectively (Figure 3 and Table 1).…”

Section: Resultsmentioning

confidence: 99%

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Low-Temperature Optical Spectroscopy of Native and Azide-Reacted Bovine Cu,Zn Superoxide Dismutase. A Structural Dynamics Study

Cupane¹,

Leone²,

Militello³

et al. 1994

Biochemistry

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The optical absorption spectra of native and N(3-)-reacted Cu,Zn superoxide dismutase (SOD) has been studied in the temperature range 300-10 K. The broad d-d bands observed in the room temperature spectrum, centered at 14,700 cm-1 (native enzyme) and at 15,550 cm-1 (N(3-)-reacted enzyme), are clearly split at low temperature into two bands each, centered at 12,835 and 14,844 cm-1 and at 14,418 and 16,300 cm-1, respectively. The thermal behavior of the 23,720 cm-1 band present in the spectrum of the native enzyme indicates that this band belongs to the His61-->Cu(II) ligand to metal charge transfer transition. Analysis of the zeroth, first, and second moments of the various bands as a function of temperature allowed us to obtain useful information on the stereodynamic properties of the metal site in SOD. In particular for the native protein, it was possible to infer a variation in the metal ligand relative position that occurs as the temperature is lowered and that likely involves all of the ligands except His61. On the other hand, the site is stabilized upon N3- binding, and in this case a variation in the metal ligand position is observed only at the level of the bound anion. The possible relation of these properties to the catalytic mechanism of the enzyme is discussed.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Low-Temperature Optical Spectroscopy of Native and Azide-Reacted Bovine Cu,Zn Superoxide Dismutase. A Structural Dynamics Study

Cupane¹,

Leone²,

Militello³

et al. 1994

Biochemistry

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“…1 and Table 2), the copper ions of which have a redox potential around 400mV (Fee & DiCorleto, 1966) and have been assigned a distorted square pyramidal structure (Richardson, 1977;Morpurgo et al, 1973). The low-temperature parameters are rather similar to those of the tetragonal species, none of which is reduced by ferrocyanide (Morpurgo et al, 1973(Morpurgo et al, , 1976, i.e. have a redox potential lower than 360mV.…”

Section: Type 2 Cumentioning

confidence: 99%

Dependence on freezing of the geometry and redox potential of type 1 and type 2 copper sites of Japanese-lacquer-tree (Rhus vernicifera) laccase

Morpurgo¹,

Calabrese²,

Desideri³

et al. 1981

Biochemical Journal

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The room-temperature e.p.r. spectrum of the Japanese-lacquer-tree (Rhus vernicifera) laccase shows A parallel (the hyperfine splitting constant) and g parallel values of both the Type 1 and Type 2 Cu appreciably different from those measured at liquid-N2 temperature. The geometry of the sites, as inferred from the room-temperature e.p.r. parameters, is more consistent with their redox properties. A rough correlation is found between A parallel and g parallel values and redox potential of the blue copper in several enzymes.

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“…The inhibition has been attributed to a direct coordination to the copper when the metal is in the oxidized state as shown by the changes of the EPR spectrum observed upon titration with these anions (5,6). The direct coordination of N 3to the oxidized copper is also demonstrated by the presence of an intense LMCT band in the optical absorption spectrum (7). The fine details of such interaction has been described by the X-ray diffraction analysis of the N 3and CNderivatives, which has shown that, besides a direct interaction with the copper, the anions also form an ion pair with the guanidinium group of the fully conserved Arg 141 (8,9).…”

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confidence: 94%

Fourier Transform Infrared Analysis of the Interaction of Azide with the Active Site of Oxidized and Reduced Bovine Cu,Zn Superoxide Dismutase

et al. 1998

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Binding of azide to the native and arginine-modified bovine Cu,Zn superoxide dismutase in the oxidized and reduced form and to the copper-free derivative has been investigated by Fourier transform infrared spectroscopy. The antisymmetric stretching band of the azide is shifted to higher energy upon coordination to the copper atom of the oxidized form of the native enzyme. Similar spectral changes occur upon interaction of the anion with the Cu-diethylenetriamine model compound. On the other hand, interaction of azide with the native reduced form of the enzyme results in a band shift toward lower energy with respect to the free anion band. The same shift is observed after reaction of the azide with free lysine or arginine but not when it is reacted with other amino acid residues. The antisymmetric band of the azide is not perturbed by addition of the reduced arginine-modified enzyme; it is likely shifted toward higher energy upon addition of oxidized arginine-modified enzyme while it is again shifted toward lower energy in the presence of the copper-free derivative of the unmodified enzyme. It is concluded that azide does not directly coordinate to the copper in the reduced form of Cu,Zn superoxide dismutase but it remains in the active-site pocket in electrostatic interaction with the guanidinium group of Arg141, which is an invariant residue in this class of enzymes.

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Studies of the metal sites of copper proteins. V. A model compound for the copper site of superoxide dismutase

Cited by 38 publications

References 14 publications

Low-Temperature Optical Spectroscopy of Native and Azide-Reacted Bovine Cu,Zn Superoxide Dismutase. A Structural Dynamics Study

Low-Temperature Optical Spectroscopy of Native and Azide-Reacted Bovine Cu,Zn Superoxide Dismutase. A Structural Dynamics Study

Dependence on freezing of the geometry and redox potential of type 1 and type 2 copper sites of Japanese-lacquer-tree (Rhus vernicifera) laccase

Fourier Transform Infrared Analysis of the Interaction of Azide with the Active Site of Oxidized and Reduced Bovine Cu,Zn Superoxide Dismutase

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