2WD4
Ascorbate Peroxidase as a heme oxygenase: w41A variant product with t-butyl peroxide
Summary for 2WD4
| Entry DOI | 10.2210/pdb2wd4/pdb |
| Related | 1OAF 1OAG 1V0H 2CL4 2GGN 2GHC 2GHD 2GHE 2GHH 2GHK 2VCF 2VCN 2VCS 2VNX 2VNZ 2VO2 |
| Descriptor | ASCORBATE PEROXIDASE, FE (III) ION, SODIUM ION, ... (6 entities in total) |
| Functional Keywords | oxidoreductase, tert-butyl peroxide, heme peroxidase, peroxide scavenge |
| Biological source | GLYCINE MAX (SOYBEAN) |
| Total number of polymer chains | 1 |
| Total formula weight | 29160.52 |
| Authors | Badyal, S.K.,Metcalfe, C.L.,Gumiero, A.,Raven, E.L.,Moody, P.C.E. (deposition date: 2009-03-19, release date: 2009-04-07, Last modification date: 2023-12-13) |
| Primary citation | Raven, E.L.,Badyal, S.K.,Eaton, G.,Mistry, S.,Pipirou, Z.,Basran, J.,Metcalfe, C.L.,Gumiero, A.,Handa, S.,Moody, P.C.E. Evidence for Heme Oxygenase Activity in a Heme Peroxidase. Biochemistry, 48:4738-, 2009 Cited by PubMed Abstract: The heme peroxidase and heme oxygenase enzymes share a common heme prosthetic group but catalyze fundamentally different reactions, the first being H(2)O(2)-dependent oxidation of substrate using an oxidized Compound I intermediate, and the second O(2)-dependent degradation of heme. It has been proposed that these enzymes utilize 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 tert-butyl hydroperoxide 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. PubMed: 19309109DOI: 10.1021/BI900118J PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.4 Å) |
Structure validation
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