2wd4

Ascorbate Peroxidase as a heme oxygenase: w41A variant product with t-butyl peroxide

spinqualitylabelsall models 2wd4, resolution 1.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2wd4 is a 1 chain structure with sequence from Glycine max. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.4Å Ligands: FE, NA, SO4, TBV Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q43758_SOYBN Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The heme peroxidases and heme oxygenase enzymes share a common heme prosthetic group but catalyse fundamentally different reactions, the first being H2O2-dependent oxidation of substrate using an oxidised Compound I intermediate, the second O2-dependent degradation of heme. It has been proposed that these enzymes utilise a common reaction intermediate, a ferric hydroperoxide species, that sits at a crossroads in the mechanism and beyond which there are two mutually exclusive mechanistic pathways. Here, we present evidence to support this proposal in a heme peroxidase. Hence, we describe kinetic data for a variant of ascorbate peroxidase (W41A) which reacts slowly with t-butylhydroperoxide and does not form the usual peroxidase Compound I intermediate; instead, structural data show that a product is formed in which the heme has been cleaved at the alpha-meso position, analogous to the heme oxygenase mechanism. We interpret this to mean that the Compound I (peroxidase) pathway is shut down, so that instead the reaction intermediate diverts through the alternative (heme oxygenase) route. A mechanism for formation of the product is proposed and discussed in the light of what is known about the heme oxygenase reaction mechanism. Evidence for Heme Oxygenase Activity in a Heme Peroxidase.,Raven E, Badyal S, Eaton G, Mistry S, Pipirou Z, Basran J, Metcalfe C, Gumiero A, Handa S, Moody P Biochemistry. 2009 Mar 23. PMID:19309109 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ascorbate peroxidase 3D structures

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