Stopped-flow Fluorescence Studies of Inhibitor Binding to Tyrosinase from Streptomyces antibioticus

Tepper, Armand W.J.W.; Bubacco, Luigi; Canters, Gerard W.

doi:10.1074/jbc.m309367200

Cited by 29 publications

(28 citation statements)

References 61 publications

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“…Based on paramagnetic NMR spectroscopy, enzyme kinetics and kinetics of fluoride binding, [3,19] we previously inferred that a single halide ion bridges the two copper ions in the active site of Ty met and that it replaces the hydroxide molecule that is present in the native form. [3,19] The typical type-3 coordination geometry is maintained in all halide-bound species.…”

Section: Discussionmentioning

confidence: 98%

“…[3,19] The typical type-3 coordination geometry is maintained in all halide-bound species. [3] Magnitude of the exchange coupling: The temperature dependence of the paramagnetic shifts could be fitted accurately to Equation (1).…”

Section: Discussionmentioning

confidence: 99%

“…[44]- [48]), which is small relative to the Zeeman energy in a 14 T field and small relative to k B T. Thus, the contribution to d pc is predicted to be negligible. [16] [28] From NMR and kinetic experiments on halide binding to Ty met , it has been found that halide-free Ty met and halide-bound Ty met are in slow exchange on the NMR time scale (the measured k off of the Cu 2 bridging F À amounts to 14 s À1 at pH 6.8 [19] ). The effects of the slow halide exchange on the relaxation character of the His protons in the active site are therefore negligible.…”

Section: Methodsmentioning

confidence: 99%

“…H NMR studies have demonstrated that Ty met contains a classical type-3 copper centre with the two copper ions in the active site each coordinated by three histidines through the N e atoms. [2,3] Furthermore, from paramagnetic NMR and kinetic studies, [3,19] it was tentatively concluded that halides bridge the two copper ions in the Ty met active site, replacing the Cu 2 bridging hydroxide that is present in native Ty met .…”

Section: Introductionmentioning

confidence: 98%

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Paramagnetic Properties of the Halide‐Bound Derivatives of Oxidised Tyrosinase Investigated by ¹H NMR Spectroscopy

Tepper

Bubacco

Canters

2006

Chemistry A European J

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The (1)H NMR relaxation characteristics of the histidines in the oxidised type-3 copper site of tyrosinase (Ty(met)) from the bacterium Streptomyces antibioticus in the halide-bound forms (Ty(met)X with X = F(-), Cl(-), Br(-)) have been determined and analysed. The (1)H NMR spectra of the Ty(met)X species display remarkably sharp, well-resolved, paramagnetically shifted (1)H signals, which originate from the protons of the six His residues coordinated to the two Cu(II) ions in the type-3 centre. From the temperature-dependence of the (1)H paramagnetic shifts the following values for the exchange-coupling parameter -2J were determined: 260 (Ty(met)F), 200 (Ty(met)Cl) and 162 cm(-1) (Ty(met)Br). The (1)H T(1) relaxation is dipolar in origin and correlates with the Cu--H distances. Electronic relaxation times tau(S) derived from the (1)H T(1) data amount to about 10(-11) s and follow the order Ty(met)F>Ty(met)Cl>Ty(met)Br. They are two orders of magnitude shorter than the tau(S) values reported for mononuclear copper systems, in accordance with the sharpness of the (1)H signals. The results corroborate the Cu(2) bridging mode of the halide ions. On the basis of the measured hyperfine interaction constants for the ligand histidine nuclei, it is concluded that 70-80 % of the spin density in the excited triplet state resides on the two copper ions and the bridging atoms.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Paramagnetic Properties of the Halide‐Bound Derivatives of Oxidised Tyrosinase Investigated by ¹H NMR Spectroscopy

Tepper

Bubacco

Canters

2006

Chemistry A European J

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“…No 3-D structural data are available for intermediate reduction states of the MCOs. Still, the semi-reduced T3 site ("half-met form") for Hc and Ty has been studied by spectroscopic techniques [104,105].…”

Section: Intramolecular Et Processes In Laccasesmentioning

confidence: 99%

Electron transfer in blue copper proteins

Farver

Pecht

2011

Coordination Chemistry Reviews

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Structure, Spectroscopy, and Function of Tyrosinase; Comparison with Hemocyanin and Catechol Oxidase

Tepper¹,

Lonardi²,

Bubacco³

et al. 2004

Handbook of Metalloproteins

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This article deals with tyrosinase, an enzyme that converts monophenols into diphenols and subsequently into orthoquinones with concomitant use of molecular oxygen as the source of oxygen atoms and oxidizing equivalents. The enzyme occurs widespread in nature. Its active center consists of a dinuclear copper site. The occurrence of tyrosinases and their biological function is reviewed. Information about primary (aa sequence, genetic organization), secondary, and tertiary structures is reviewed and, where appropriate, compared with similar information about related proteins with a dinuclear Cu site (hemocyanins, catechol oxidase). Methods to produce and purify tyrosinase are reviewed. Spectroscopic studies (optical; EPR, NMR, EXAFS) are reviewed in relation to the enzyme mechanism, which is discussed at the end of the article.

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Stopped-flow Fluorescence Studies of Inhibitor Binding to Tyrosinase from Streptomyces antibioticus

Cited by 29 publications

References 61 publications

Paramagnetic Properties of the Halide‐Bound Derivatives of Oxidised Tyrosinase Investigated by ¹H NMR Spectroscopy

Paramagnetic Properties of the Halide‐Bound Derivatives of Oxidised Tyrosinase Investigated by ¹H NMR Spectroscopy

Electron transfer in blue copper proteins

Structure, Spectroscopy, and Function of Tyrosinase; Comparison with Hemocyanin and Catechol Oxidase

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Stopped-flow Fluorescence Studies of Inhibitor Binding to Tyrosinase from Streptomyces antibioticus

Cited by 29 publications

References 61 publications

Paramagnetic Properties of the Halide‐Bound Derivatives of Oxidised Tyrosinase Investigated by 1H NMR Spectroscopy

Paramagnetic Properties of the Halide‐Bound Derivatives of Oxidised Tyrosinase Investigated by 1H NMR Spectroscopy

Electron transfer in blue copper proteins

Structure, Spectroscopy, and Function of Tyrosinase; Comparison with Hemocyanin and Catechol Oxidase

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Product

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Paramagnetic Properties of the Halide‐Bound Derivatives of Oxidised Tyrosinase Investigated by ¹H NMR Spectroscopy

Paramagnetic Properties of the Halide‐Bound Derivatives of Oxidised Tyrosinase Investigated by ¹H NMR Spectroscopy