Structure–function correlations in tyrosinases

Kanteev, M.; Goldfeder, Mor; Fishman, Ayelet

doi:10.1002/pro.2734

Cited by 177 publications

(148 citation statements)

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“…Dioxygen is reversibly bound as peroxide in aside-on bridging coordination. [4,15,17,18] Recently,t he Fishman group presented crystal structures of the tyrosinase from Bacillus megaterium (TyrBm)with and without bound mono-or diphenolic substrates such as tyrosine, p-tyrosol, and l-DOPA. COs,i nc ontrast, can only perform the latter reaction (diphenolase activity).…”

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confidence: 99%

“…[15,16] Besides the natural substrate tyrosine TYs also hydroxylate other monophenols in ortho-position to diphenols, followed by oxidation to ortho-quinones (monophenolase activity). [17,18] They suggested that ah ighly conserved glutamate and an asparagine bind and activate aw ater molecule towards deprotonation of monophenols,w hich is required for tyrosinase activity.H ere we provide the first direct experimental proof of this hypothesis. [15] Although being of significant biological, medical, and economic importance,t he molecular basis of the functional discrimination between tyrosinase and catechol oxidase is still unclear.…”

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confidence: 99%

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Tyrosinase versus Catechol Oxidase: One Asparagine Makes the Difference

2016

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Tyrosinases mediate the ortho-hydroxylation and two-electron oxidation of monophenols to ortho-quinones. Catechol oxidases only catalyze the oxidation of diphenols. Although it is of significant interest, the origin of the functional discrimination between tyrosinases and catechol oxidases has been unclear. Recently, it has been postulated that a glutamate and an asparagine bind and activate a conserved water molecule towards deprotonation of monophenols. Here we demonstrate for the first time that a polyphenoloxidase, which exhibits only diphenolase activity, can be transformed to a tyrosinase by mutation to introduce an asparagine. The asparagine and a conserved glutamate are necessary to properly orient the conserved water in order to abstract a proton from the monophenol. These results provide direct evidence for the crucial importance of a proton shuttle for tyrosinase activity of type 3 copper proteins, allowing a consistent understanding of their different chemical reactivities.

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Tyrosinase versus Catechol Oxidase: One Asparagine Makes the Difference

2016

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“…Tyrosinase (EC 1.14.18.1), a multifunctional copper‐containing oxidase, is the key rate‐limiting enzyme in melanin synthesis, which catalyzes both the monophenolase reaction and diphenolase reaction (Kanteev, Goldfeder, & Fishman, ). Tyrosinase inhibitor can cure skin pigmentation or whiten skin (Kim et al., ).…”

Section: Introductionmentioning

confidence: 99%

Extraction optimization and purification of anthocyanins from Lycium ruthenicum Murr. and evaluation of tyrosinase inhibitory activity of the anthocyanins

Shen

Liu

Liang

et al. 2020

Journal of Food Science

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The aim of this study was to extract and purify anthocyanins from Lycium ruthenicum Murr. and evaluate their tyrosinase inhibitory activity. Response surface methodology was devoted to optimize enzyme‐assisted extraction of anthocyanins from L. ruthenicum dried fruits. Extraction at 38 °C for 37 min using water‐containing pectinase (52.04 mg/100 g dried fruit) rendered an anthocyanin extraction yield of 19.51 ± 0.21 mg/g. The purified anthocyanins were separated from the extract by macroporous resin XDA‐6. Antioxidant tests in vitro suggested that the extract and the purified anthocyanins exhibited a potent 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging capacity, 2,2‐azino‐bis‐3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) radical scavenging capacity, hydroxyl radical scavenging capacity, superoxide radical scavenging capacity, and total reducing power. Thirteen anthocyanins from L. ruthenicum dried fruits were analyzed by HPLC‐MS. Moreover, the purified anthocyanins had inhibitory effect on tyrosinase monophenolase (IC50 = 1.483 ± 0.058 mg/mL), and the type of inhibition was competitive inhibition (Ki = 39.83 ± 1.4 mg/mL). The maximum inhibitory activity of the purified anthocyanins (3.00 mg/mL) on tyrosinase diphenolase was 42.16 ± 0.77%, and the type of inhibition was anticompetitive inhibition (Kis = 2.387 ± 0.10 mg/mL). Practical Application The anthocyanins from L. ruthenicum dried fruits can be used as tyrosinase inhibitors in medicine, cosmetics, and food preservation industries.

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“…15,19 Di-Mn(II/III) catalases catalyze the disproportionation of hydrogen peroxide. 20 Cytochrome c oxidase (C c O) catalyzes the four-electron reduction of O 2 21–23 while water is oxidized to O 2 at the Mn 4 CaO 5 oxygen evolving complex (OEC) of photosystem II.…”

Section: Introductionmentioning

confidence: 99%

De Novo Design of Tetranuclear Transition Metal Clusters Stabilized by Hydrogen-Bonded Networks in Helical Bundles

et al. 2018

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De novo design provides an attractive approach to test the mechanism by which metalloproteins define the geometry and reactivity of their metal ion cofactors. While there has been considerable progress in designing proteins that bind transition metal ions including iron-sulphur clusters, the design of tetranuclear clusters with oxygen-rich environments has not been accomplished. Here, we describe the design of tetranuclear clusters, consisting of four Zn2+ and four carboxylate oxygens situated at the vertices of a distorted cube-like structure. The tetra-Zn2+ clusters are bound at a buried site within a four-helix bundle, with each helix donating a single carboxylate (Glu or Asp) and imidazole (His) ligand, as well as second- and third-shell ligands. Overall, the designed site consists of four Zn2+ and 16 polar sidechains in a fully connected hydrogen-bonded network. The designed proteins have apolar cores at the top and bottom of the bundle, which drive the assembly of the liganding residues near the center of the bundle. The steric bulk of the apolar residues surrounding the binding site was varied to determine how subtle changes in helix-helix packing affect the binding site. The crystal structures of two of four proteins synthesized were in good agreement with the overall design; both formed a distorted cuboidal site stabilized by flanking second and third-shell interactions that stabilize the primary ligands. A third structure bound a single Zn2+ in an unanticipated geometry and the fourth bound multiple Zn2+ at multiple sites at partial occupancy. The metal-binding and conformational properties of the helical bundles in solution, probed by circular dichroism spectroscopy, analytical ultracentrifugation and NMR, were consistent with the crystal structures.

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Structure–function correlations in tyrosinases

Cited by 177 publications

References 58 publications

Tyrosinase versus Catechol Oxidase: One Asparagine Makes the Difference

Tyrosinase versus Catechol Oxidase: One Asparagine Makes the Difference

Extraction optimization and purification of anthocyanins from Lycium ruthenicum Murr. and evaluation of tyrosinase inhibitory activity of the anthocyanins

De Novo Design of Tetranuclear Transition Metal Clusters Stabilized by Hydrogen-Bonded Networks in Helical Bundles

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