Oxygen Binding to Tyrosinase from Streptomyces antibioticus Studied by Laser Flash Photolysis

Hirota, Shun; Kawahara, Takumi; Lonardi, Emanuela; Waal, Ellen de; Funasaki, Noriaki; Canters, Gerard W.

doi:10.1021/ja0541128

Cited by 18 publications

(17 citation statements)

References 21 publications

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“…To convert phenols such as tyrosine to L-DOPAquinone, Ty binds dioxygen with a measured equilibrium binding constant of 16.5 – 46.6 µM, 438,439 falling within the range of oxygen affinities found in mollusc Hc (Section 3.1.2). The rate of O 2 binding to deoxy-Ty (19–23 µM −1 s −1 ) 438,440 is also similar to mollusc Hc (5–30 µM −1 s −1 ). 203,303,305 During catalysis, three states of Ty (and CaOx) have been characterized; deoxy ([Cu(I) 2 ] 2+ ), oxy ([Cu(II) 2 O 2 ] 2+ ), and met-Ty (two Cu(II)’s bridged and antiferromagnetically coupled by a hydroxide ligand) (Figure 58 and 59).…”

Section: Copper Active Sites That Activate Dioxygenmentioning

confidence: 61%

Copper Active Sites in Biology

et al. 2014

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Section: Copper Active Sites That Activate Dioxygenmentioning

confidence: 61%

Copper Active Sites in Biology

et al. 2014

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“…Consistent with the structural similarity, the holo-pro-tyrosinase has no tyrosinase activity, but the reduced pro-tyrosinase (deoxyform), produced by the reduction of the as-isolated enzyme with hydroxylamine (reductant), exhibited a reversible dioxygenbinding ability and the dissociation constant (K d ) was determined to be 52¯M. 35 As the K d value of molluscan hemocyanin was reported as 90¯M, 55 these affinity toward dioxygen is in a similar range. Leu2830 residue in the octopus hemocyanin Based on the structural similarity of the functional unit g of molluscan hemocyanin with melB pro-tyrosinase, we expected that the molluscan hemocyanin can get the phenolase and catecholase activities under some denaturation conditions.…”

Section: Induction Of Tyrosinase Activity To Octopus (Molluscan) Hemomentioning

confidence: 73%

Controlling Dicopper Protein Functions

Fujieda¹,

Itoh²

2016

Bulletin of the Chemical Society of Japan

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Maturation processes of dinuclear copper proteins such as tyrosinase, catechol oxidase, and hemocyanin have been a long-standing mystery in copper protein chemistry. Until now, several crystal structures have revealed that these copper proteins share a similar dinuclear copper active site, where each copper ion is ligated by three histidine imidazoles, and binds molecular oxygen in a side-on fashion to form a (¯-η 2 :η 2 -peroxido)dicopper(II) species not only as the dioxygen-adduct in oxy-hemocyanins but also as the key reactive intermediate for the hydroxylation of phenols to catechols (phenolase reaction) and the oxidation of catechols to o-quinones (catecholase reaction) in tyrosinases and catechol oxidases. Recently, we have succeeded in determining the high-resolution crystal structures of the recombinant pro-form of yellow koji mold tyrosinase to find the existence of a distinct C-terminal domain containing a CXXC unit, that is the common sequence motif of the copper chaperons. Thus, the C-terminal domain apparently acts as a copper chaperon, helping construction of the dinuclear copper active site of tyrosinase. Furthermore, we have found that the proteolytic cleavage of the C-terminal domain from the pro-form (inactive-form) of tyrosinase greatly enhances the tyrosinase activity, thus suggesting that the Cterminal domain also acts as a shielding domain to regulate the enzymatic activity. In fact, overall structure of the pro-form resembles the structure of one of the functional units of octopus hemocyanin (oxygen carrier protein), which also has a similar C-terminal domain prohibiting the monooxygenase activity. On the basis of these results together with the detailed kinetic and spectroscopic analyses, the maturation process of the dinuclear copper proteins is discussed to provide new insights into the regulation mechanism of the dicopper protein functions; dioxygen binding and activation. We have also succeeded in evolving phenolase activity from molluscan and arthropod hemocyanins by treating them with a hydrolytic enzyme or an acid, and demonstrated that the reaction mechanism of their phenolase activity is the same to that of tyrosinase itself, that is the electrophilic aromatic substitution mechanism. Furthermore, we have developed an artificial dicopper protein exhibiting catecholase activity using metallo-β-lactamase, a dinuclear zinc enzyme, as a metal binding platform.

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“…Laser flash photolysis has been used by Hirota et al to examine O 2 binding by tyrosinase (Tyr) from Streptomyces antibioticus 44. Following O 2 -photoejection from oxy-Tyr to form deoxy-Tyr, reformation of the starting dicopper(II)-μ-η 2 :η 2 -peroxo species was observed while an initial 1:1 Cu/O 2 adduct was not detected.…”

Section: Discussionmentioning

confidence: 99%

“…However, even following photoexcitation and subsequent dissociation of O 2 from oxy-Tyr44 and/or oxy-Hc,45,46 a Cu II B -O 2 •− adduct has not been detected and instead only implicated through theoretical modeling 16,47. Never-the-less, Hirota, Bubacco, and coworkers recently used flash photolysis and complementary K-edge X-ray absorption spectroscopy (XAS) measurements to show that the O 2 binding rate constant ( k O2 ) for a deoxy-Hc was dependent on the copper(I) coordination geometry 45.…”

Section: Introductionmentioning

confidence: 99%

CO and O₂ Binding to Pseudo-tetradentate Ligand−Copper(I) Complexes with a Variable N-Donor Moiety: Kinetic/Thermodynamic Investigation Reveals Ligand-Induced Changes in Reaction Mechanism

2010

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The kinetics, thermodynamics, and coordination dynamics for O 2 and CO 1:1 binding to a series of pseudo-tetradentate ligand-copper(I)-complexes ( D LCu I ) to give Cu I /O 2 and Cu I /CO product species are reported. The D LCu I series possess an identical tridentate core structure where the cuprous ion binds to the bispicolylamine (L) fragment. D L also contains a fourth variable N-donor moiety {D = benzyl (Bz); pyridyl (Py); imidazolyl (Im); dimethylamino (NMe 2 -); tert-butylphenyl pyridyl (TBP); quinolyl (Q)}. The structural characteristics of D LCu I -CO and D LCu I are detailed, with X-ray crystal structures reported for TBP LCu I -CO, Bz LCu I -CO, and Q LCu I . Infrared studies (solution and solid-state) confirm that D LCu I -CO possess the same four-coordinate core structure in solution with the variable D moiety 'dangling', i.e. not coordinated to the copper(I) ion. Other trends observed for the present series appear to derive from the degree to which the D-group interacts with the cuprous ion center. Electrochemical studies reveal close similarities of behavior for Im LCu I and NMe 2 LCu I (as well as for TBP LCu I and Q LCu I ), which relate to the O 2 -binding kinetics and thermodynamics. Equilibrium CO binding data (K CO , ΔH°, ΔS°) were obtained by conducting UV-visible spectrophotometric CO titrations, while CO binding kinetics and thermodynamics (k CO ; ΔH ‡ , ΔS ‡ ) were measured through variable temperature (193 K -293 K) transient absorbance laser flash photolysis experiments, λ ex = 355 nm. Carbon monoxide dissociation rate constants (k −CO ) and corresponding activation parameters (ΔH ‡ , ΔS ‡ ) have also been obtained. CO binding to D LCu I follows an associative mechanism with the increased donation from D leading to higher k CO values. Unlike that seen in previous work, the K CO values increased as the k CO and k −CO values declines; the latter decreased at a faster rate. By using the 'flash-and-trap' method (λ ex = 355 nm ; 188 K -218 K), the kinetics and thermodynamics (k O2 ; ΔH ‡ , ΔS ‡ ) for O 2 binding to NMe 2 LCu I and Im LCu I were measured and compared to Py LCu I . A surprising change in the O 2 binding mechanism was deduced from the thermodynamic ΔS ‡ values observed, associative for Py LCu I but dissociative for NMe 2 LCu I and Im LCu I ; these results are interpreted as arising from a difference in the timing of electron transfer from copper(I) to O 2 as this molecule coordinates and a tetrahydrofuran (THF) solvent molecule dissociates. The change in mechanism was not simply related to alterations in D LCu II/I geometries or the order that O 2 / THF coordinate. The equilibrium O 2 binding constant (K O2 ; ΔH°, ΔS°) and O 2 dissociation rate constants (k −O2 ; ΔH ‡ , ΔS ‡ ) were also determined. Overall the results demonstrate that subtle changes in the coordination environment, as occurs over time through evolution in nature or through controlled ligand design in synthetic systems, dictate to a critically detailed level the observed chemistry in terms of reaction k...

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Oxygen Binding to Tyrosinase from Streptomyces antibioticus Studied by Laser Flash Photolysis

Cited by 18 publications

References 21 publications

Copper Active Sites in Biology

Copper Active Sites in Biology

Controlling Dicopper Protein Functions

CO and O₂ Binding to Pseudo-tetradentate Ligand−Copper(I) Complexes with a Variable N-Donor Moiety: Kinetic/Thermodynamic Investigation Reveals Ligand-Induced Changes in Reaction Mechanism

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Oxygen Binding to Tyrosinase from Streptomyces antibioticus Studied by Laser Flash Photolysis

Cited by 18 publications

References 21 publications

Copper Active Sites in Biology

Copper Active Sites in Biology

Controlling Dicopper Protein Functions

CO and O2 Binding to Pseudo-tetradentate Ligand−Copper(I) Complexes with a Variable N-Donor Moiety: Kinetic/Thermodynamic Investigation Reveals Ligand-Induced Changes in Reaction Mechanism

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Product

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CO and O₂ Binding to Pseudo-tetradentate Ligand−Copper(I) Complexes with a Variable N-Donor Moiety: Kinetic/Thermodynamic Investigation Reveals Ligand-Induced Changes in Reaction Mechanism