Journal ArticleDOI
Crystal structure of a plant catechol oxidase containing a dicopper center.
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TLDR
Based on biochemical, spectroscopic and the presented structural data, a catalytical mechanism is proposed in which one of the oxygen atoms of the diphenolic substrate binds to CuB ofThe oxygenated enzyme.Abstract:
Catechol oxidases are ubiquitous plant enzymes containing a dinuclear copper center. In the wound-response mechanism of the plant they catalyze the oxidation of a broad range of ortho-diphenols to the corresponding o-quinones coupled with the reduction of oxygen to water. The crystal structures of the enzyme from sweet potato in the resting dicupric Cu(II)-Cu(II) state, the reduced dicuprous Cu(I)-Cu(I) form, and in complex with the inhibitor phenylthiourea were analyzed. The catalytic copper center is accommodated in a central four-helix-bundle located in a hydrophobic pocket close to the surface. Both metal binding sites are composed of three histidine ligands. His 109, ligated to the CuA site, is covalently linked to Cys 92 by an unusual thioether bond. Based on biochemical, spectroscopic and the presented structural data, a catalytical mechanism is proposed in which one of the oxygen atoms of the diphenolic substrate binds to CuB of the oxygenated enzyme.read more
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Journal ArticleDOI
Copper Active Sites in Biology
Edward I. Solomon,David E. Heppner,Esther M. Johnston,Jake W. Ginsbach,Jordi Cirera,Munzarin F. Qayyum,Matthew T. Kieber-Emmons,Christian H. Kjaergaard,Ryan G. Hadt,Li Tian +9 more
TL;DR: This review presents in depth discussions of all these classes of Cu enzymes and the correlations within and among these classes, as well as the present understanding of the enzymology, kinetics, geometric structures, electronic structures and the reaction mechanisms these have elucidated.
Journal ArticleDOI
Polyphenol oxidases in plants and fungi: going places? A review.
TL;DR: The more recent reports on polyphenol oxidase in plants and fungi are reviewed and many details about structure and probably function of PPO have been revealed, but some of the basic questions raised over the years remain to be answered.
Journal ArticleDOI
Applications of laccases and tyrosinases (phenoloxidases) immobilized on different supports: a review
TL;DR: All the research efforts that have been spent to immobilize laccase and tyrosinase for various applications, including synthetic and analytical purposes, bioremediation, wastewater treatment, and must and wine stabilization are summarized.
Journal ArticleDOI
Oxygen Binding, Activation, and Reduction to Water by Copper Proteins
TL;DR: The spectroscopic and quantum-mechanical study of these oxygen intermediates has defined geometric- and electronic-structure/function correlations, and developed detailed reaction coordinates for the reversible binding of O(2), hydroxylation, and H-atom abstraction from different substrates, and the reductive cleavage of the O-O bond in the formation water.
Journal ArticleDOI
Crystallographic Evidence That the Dinuclear Copper Center of Tyrosinase Is Flexible during Catalysis
TL;DR: Crystal structures of copper-bound and metal-free tyrosinase in a complex with ORF378 designated as a “caddie” protein suggest that the caddie protein covers the hydrophobic molecular surface of tyosinase and interferes with the binding of a substrate tyrosine to the catalytic site of tyOSinase.
References
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Multicopper Oxidases and Oxygenases
TL;DR: Copper sites have historically been divided into three classes based on their spectroscopic features, which reflect the geometric and electronic structure of the active site: type 1 or blue copper, type 2 (T2) or normal copper, and type 3 (T3) or coupled binuclear copper centers.