1gyc: Difference between revisions
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==Overview== | ==Overview== | ||
Laccase is a polyphenol oxidase, which belongs to the family of blue, multicopper oxidases. These enzymes catalyze the one-electron oxidation of, four reducing-substrate molecules concomitant with the four-electron, reduction of molecular oxygen to water. Laccases oxidize a broad range of, substrates, preferably phenolic compounds. In the presence of mediators, fungal laccases exhibit an enlarged substrate range and are then able to, oxidize compounds with a redox potential exceeding their own. Until now, only one crystal structure of a laccase in an inactive, type-2, copper-depleted form has been reported. We present here the first crystal, structure of an active laccase containing a full complement of coppers, the complete polypeptide chain together with seven carbohydrate moieties., ... | Laccase is a polyphenol oxidase, which belongs to the family of blue, multicopper oxidases. These enzymes catalyze the one-electron oxidation of, four reducing-substrate molecules concomitant with the four-electron, reduction of molecular oxygen to water. Laccases oxidize a broad range of, substrates, preferably phenolic compounds. In the presence of mediators, fungal laccases exhibit an enlarged substrate range and are then able to, oxidize compounds with a redox potential exceeding their own. Until now, only one crystal structure of a laccase in an inactive, type-2, copper-depleted form has been reported. We present here the first crystal, structure of an active laccase containing a full complement of coppers, the complete polypeptide chain together with seven carbohydrate moieties., Despite the presence of all coppers in the new structure, the folds of the, two laccases are quite similar. The coordination of the type-3 coppers, however, is distinctly different. The geometry of the trinuclear copper, cluster in the Trametes versicolor laccase is similar to that found in the, ascorbate oxidase and that of mammalian ceruloplasmin structures, suggesting a common reaction mechanism for the copper oxidation and the, O(2) reduction. In contrast to most blue copper proteins, the type-1, copper in the T. versicolor laccase has no axial ligand and is only 3-fold, coordinated. Previously, a modest elevation of the redox potential was, attributed to the lack of an axial ligand. Based on the present structural, data and sequence comparisons, a mechanism is presented to explain how, laccases could tune their redox potential by as much as 200 mV. | ||
==About this Structure== | ==About this Structure== | ||
1GYC is a | 1GYC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Trametes_versicolor Trametes versicolor] with NAG, CU and IPA as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Laccase Laccase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.10.3.2 1.10.3.2] Structure known Active Site: CU1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1GYC OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
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Revision as of 14:33, 5 November 2007
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CRYSTAL STRUCTURE DETERMINATION AT ROOM TEMPERATURE OF A LACCASE FROM TRAMETES VERSICOLOR IN ITS OXIDISED FORM CONTAINING A FULL COMPLEMENT OF COPPER IONS
OverviewOverview
Laccase is a polyphenol oxidase, which belongs to the family of blue, multicopper oxidases. These enzymes catalyze the one-electron oxidation of, four reducing-substrate molecules concomitant with the four-electron, reduction of molecular oxygen to water. Laccases oxidize a broad range of, substrates, preferably phenolic compounds. In the presence of mediators, fungal laccases exhibit an enlarged substrate range and are then able to, oxidize compounds with a redox potential exceeding their own. Until now, only one crystal structure of a laccase in an inactive, type-2, copper-depleted form has been reported. We present here the first crystal, structure of an active laccase containing a full complement of coppers, the complete polypeptide chain together with seven carbohydrate moieties., Despite the presence of all coppers in the new structure, the folds of the, two laccases are quite similar. The coordination of the type-3 coppers, however, is distinctly different. The geometry of the trinuclear copper, cluster in the Trametes versicolor laccase is similar to that found in the, ascorbate oxidase and that of mammalian ceruloplasmin structures, suggesting a common reaction mechanism for the copper oxidation and the, O(2) reduction. In contrast to most blue copper proteins, the type-1, copper in the T. versicolor laccase has no axial ligand and is only 3-fold, coordinated. Previously, a modest elevation of the redox potential was, attributed to the lack of an axial ligand. Based on the present structural, data and sequence comparisons, a mechanism is presented to explain how, laccases could tune their redox potential by as much as 200 mV.
About this StructureAbout this Structure
1GYC is a Single protein structure of sequence from Trametes versicolor with NAG, CU and IPA as ligands. Active as Laccase, with EC number 1.10.3.2 Structure known Active Site: CU1. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of a laccase from the fungus Trametes versicolor at 1.90-A resolution containing a full complement of coppers., Piontek K, Antorini M, Choinowski T, J Biol Chem. 2002 Oct 4;277(40):37663-9. Epub 2002 Aug 5. PMID:12163489
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