Resonance Raman spectra of copper-sulfur complexes and the blue copper protein question

Ferris, Nancy S.; Woodruff, William H.; Rorabacher, D. B.; Jones, Thomas; Ochrymowycz, L. A.

doi:10.1021/ja00486a055

Cited by 76 publications

(36 citation statements)

References 13 publications

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“…The data provides strong evidence for the assignment of low-frequency (∼350-400 cm −1 ) peak in the resonance Raman spectra of the blue coppermethionine as a Cu−S (methionine) stretching vibration 20 and low-frequency (∼412 cm −1 ) peak as a Ni−S (methionine) stretching vibration 21 . …”

Section: Analysis Of Methionine Template Analcime Adsorption By Energmentioning

confidence: 67%

“…This affinity is in agreement with the reports for other hydrous solids such as activated carbon 19 and has been related to the first equilibrium hydrolysis constant (− log K 1 ): Cu(II) = 7.9 and Ni(II) = 9.9. It has been confirmed that higher first hydrolysis constantly lowers the degree of solvation of metal ions 20 . Furthermore, the results indicated that methionine template analcime shows higher adsorption ability than template-free analcime.…”

Section: Equal the Linear Form Of Langmuir Equation Ismentioning

confidence: 87%

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Methionine templated analcime for enhancing heavy metal adsorption

Tilami¹,

Azizi²

2017

ScienceAsia

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Zeolites are effective adsorbents to remove heavy metals from aqueous solutions. To investigate the role of the template on enhancing the ability of zeolites to absorb metals, methionine amino acid was introduced to zeolite synthesis gel to produce a modified analcime zeolite. Afterwards, adsorption of Cu(II) and Ni(II) cations on templatefree analcime and methionine-templated analcime were studied and the experimental data were fitted with Freundlich and Langmuir equations in order to obtain the sorption parameters. Batch experiments were carried out to evaluate Cu(II) and Ni(II) adsorption at different pH values, heavy metals concentrations, and removal intervals. The results showed that the metal removal efficiency was strongly dependent on the pH of the solutions. The analcime zeolites absorbed Cu(II) more readily than Ni(II). Furthermore, methionine-templated analcime exhibited a higher potential for heavy metal removal than the template-free zeolite. Raman spectra indicated that the presence of a methionine template during analcime zeolite synthesis could create a complex structure of Cu−S (methionine)/zeolite and Ni−S (methionine)/zeolite. Thus introducing a sulphur-containing template such as methionine may give further possibilities to improve the metal removal efficiency of zeolites.

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Section: Analysis Of Methionine Template Analcime Adsorption By Energmentioning

confidence: 67%

Section: Equal the Linear Form Of Langmuir Equation Ismentioning

confidence: 87%

Methionine templated analcime for enhancing heavy metal adsorption

Tilami¹,

Azizi²

2017

ScienceAsia

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“…There is now a fair amount of experimental data which substantiates the occurrence of the S(thioether) + Cu charge transfer transitions in the 380-570-nm region [24,28,29], whereas charge transfer bands involving n(N)im + Cu(I1) transitions occur well into the ultraviolet region of the spectrum (250-320 nm) [30,31]. Since the a(S)(Cys) + Cu(l1) transition in blue proteins appears at about 600 nm and a model macrocyclic compound containing the trigonal bipyramidal Cu(II)N4S(mercapeptide) chromophore displays an analogous transition at 360 nm, Fawcett et al [29] argue that a similar red shift (z 11 000 cm-') may be assumed for the n(N)im-+Cu(II) transition which would lie consequently at about 450 nm.…”

Section: T~pe-1 Coppermentioning

confidence: 99%

“…Accordingly, the band at 260-270 cm-' in the resonance Raman spectra of blue-copper proteins has been assigned to the CuS(Met) or CuS(disu1fide) stretch (stellacyanin contains one cysteine and one cystine and no methionine and displays a band at 265 cm-' in its spectrum) [24]. From the evidence provided by these data it seems quite reasonable to assume for type-Ib copper a similar structure to that of type-I copper in plastocyanin and azurin.…”

Section: T~pe-1 Coppermentioning

confidence: 99%

“…From the evidence provided by these data it seems quite reasonable to assume for type-Ib copper a similar structure to that of type-I copper in plastocyanin and azurin. Moreover, on the basis of the resonance Raman results [24], we have assigned the bands at 380 nm and 450 nm in the C D spectra of type-Ib copper to a rr(S)(Met) + Cu(1l) and a n(S)(Met) + Cu(I1) charge transfer transition respectively. By analogy the same assignment holds for the C D spectra of other blue proteins containing one type-I copper center.…”

Section: T~pe-1 Coppermentioning

confidence: 99%

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Spectroscopic and Photoreduction Studies of Copper Chromophores in Ceruloplasmin

Hervé

Garnier

Tosi

et al. 1981

European Journal of Biochemistry

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Photoreduction of native ceruloplasmin, using the 454.5-nm line of an Ar' laser, enables the identification of type-Ia, type-Ib and type-I1 copper. The circular dichroic spectra of N; -bound type-I1 copper and SCW-bound type-I1 copper are obtained by the same procedure after anionic treatment of ceruloplasmin. From circular dichroic and resonance Raman evidence it appears that some of type-Ia and type-Ib copper ligands differ. Type-Ib copper ligands seem to the same as type-I copper in plastocyanin and azurin. Even though type-Ib copper is coordinated to one sulfur of cysteine and one sulfur of methionine (or disulfide of cystine), the methionine sulfur is not a ligand for type-Ia copper.Ceruloplasmin is a plasma copper oxidase containing six or seven copper ions. Six of them are essential to enzymatic activity, while the seventh is easily separated by chelex treatment. From the remaining six atoms, three are detectable by electron paramagnetic resonance (EPR); two of them arc the so-called type I, or 'blue copper' ions, that show abnormally small EPR hyperfine splitting and absorb strongly at 600 nm (E/CU = 5500 M-' cm-'), the other one is type I1 (non-blue) copper characterized by a normal EPR hyperfine splitting, i.e. that observed in planar tetragonal copper complexes. Of the three copper ions not detectable by EPR, two of them are of type 111, thought to form an anti-ferromagnetic coupled pair, which absorb at 330 nm. The sixth copper is known as type IV [I].The intense absorption at 600 nm characteristic of type-I copper has been assigned to a S(Cys) --+ Cu(I1) ligand-to-metal charge transfer transition [2]. The crystal X-ray structure of two blue-copper proteins containing one type-I center has confirmed this assignment by demonstrating the presence of four ligands: one sulfur from cysteine (S), one sulfur from methionine (S*) and two imidazole nitrogens from histidine forming a distorted tetrahedral coordination geometry around the metal (Cu Nz SS*) [3,4]. The two type-I copper sites present in ceruloplasmin differ in their redox potential [5], reoxidation rate [6], electron paramagnetic signal [7], circular dichroism [8] and resonance Raman patterns [9]. They also show different photochemical behaviour and quantum yield Using EPR and absorption studies it has been demonstrated that inhibitory anions like fluoride and azide bind to type-I1 copper in ceruloplasmin [ll]. C D and absorption evidence, on the other hand, have shown that the overall effect of addition of inhibitory anions such as azide, thiocyanate and cyanate is not only coordination to type-I1 copper but also the simultaneous disruption of the S(Cys)-Cu(I1) bond of one of the two type-I copper sites [8].In a recent study on the interaction of laser radiation on human ceruloplasmin we have shown that, under the effect of radiation of wavelengths ranging over 514.5-360 nm, both type-I copper ions are reduced while type-I1 copper remains unchanged [lo]. An analogous result was obtained by using a mercury lamp [12]. We have been able to calculat...

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